ARTICLE | doi:10.20944/preprints202203.0367.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Salmonella; Novel Antibacterial Agents; Cannabinoids
Online: 28 March 2022 (14:30:09 CEST)
Products derived from Cannabis sativa have gained increased interest and popularity. As these products become common amongst the public, the heath and potential therapeutic values associated with hemp have become a premier focus of research. While the psychoactive and medicinal properties of Cannabis products have been extensively highlighted in literature, the antibacterial properties of CBD have not been explored in depth. This research serves to examine the antibacterial potential of CBD against Salmonella newington and Salmonella typhimurium. In this study we observed bacterial response to CBD exposure through biological assays, bacterial kinetics, and fluorescence microscopy. Additionally, comparative studies between CBD and ampicillin were conducted against Salmonella typhimurium and Salmonella newington to determine comparative efficacy. Furthermore, we observed potential resistance development of our Salmonella spp. against CBD treatment.
REVIEW | doi:10.20944/preprints202203.0009.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: bee propolis; biological activity; antibacterial
Online: 1 March 2022 (08:30:12 CET)
Antibiotic resistance was described soon discovery of penicillin by Fleming. In recent years, there has been increasing research interest in the development of alternatives to address this problem. Natural products, mainly, have long been considered as sources of drugs, and a great part of pharmaceuticals available in modern medicine are directly or indirectly derived from natural sources. propolis been used to treat human diseases since ancient times, propolis, is a natural resinous mixture produced by honeybees (Apis mellifera) from collected parts of plants, he is increasingly recognized by their wide range of biological and pharmacological properties, As anti- infective agent, combination synergy with standard antibiotics could be very promising alternative strategy
COMMUNICATION | doi:10.20944/preprints202112.0291.v1
Subject: Chemistry And Materials Science, Food Chemistry Keywords: silver; chitosan; hydrogel; antibacterial; grape
Online: 17 December 2021 (14:46:05 CET)
Hydrogel antibacterial agent is an ideal antibacterial material because of it could diffuses antibacterial molecules into the decayed area by providing a suitable microenvironment and the hydrogel acts as a protective barrier on the decay interface. The biocompatibility and biodegradation make the removal process easily which were widely used in medical fields. However, there have been few reports on its application for controlling postharvest diseases in fruit. In this study, the Chitosan-Ag (CS-Ag) complex hydrogels were prepared using the physical crosslinking method, which used for controlling postharvest diseases in grape. The prepared hydrogels were stable for a long period at room temperature. The structure and surface morphology of CS-Ag composite hydrogels were characterized by UV-Vis, FTIR, SEM, and XRD. The inhibitory effects of CS-Ag hydrogel on disease in grape caused by P. expansum, A. niger and B. cinerea were investigated both in vivo and in vitro. The remarkable antibacterial activity of CS-Ag hydrogels was mainly due to the synergistic antibacterial and antioxidant effects of CS and Ag. Preservation test showed that the CS-Ag hydrogel had positive fresh-keeping effect. This revealed CS-Ag hydrogels plays a critical role in controlling fungal disease in grape.
ARTICLE | doi:10.20944/preprints202011.0149.v1
Subject: Chemistry And Materials Science, Biomaterials Keywords: turmeric; neem; antibacterial; antifungal; polyethylene
Online: 3 November 2020 (13:58:22 CET)
With the increased scientific interest in green technologies, many researches have been focused on the production of polymeric composites containing naturally occurring reinforcing particles. Apart from increasing mechanical properties, these additions can have a wide range of interesting effects, such as increasing the resistance to bacterial and fungal colonization. In this work, different amounts of two different natural products, namely neem and turmeric, have been added to polyethylene to act as a natural antibacterial and antifungal product for food packaging applications. Microscopic and spectroscopic characterization showed that fractions up to 5% of these products can be dispersed into low-molecular weight polyethylene, while higher amounts could not be properly dispersed and resulted in an inhomogeneous, fragile composite. In vitro testing conducted with Escherichia coli, Staphylococcus aureus and Candida albicans showed a reduced proliferation of pathogens when compared to the polyethylene references. In particular, turmeric, resulted to be more effective against E. coli when compared to neem, while they had similar performances against S. aureus. Against C. albicans, only neem was able to show a good antifungal behavior, at high concentrations. Tensile testing showed that the addition of reinforcing particles reduces the mechanical properties of polyethylene, and, in the case of turmeric, it is further reduced by UV irradiation.
ARTICLE | doi:10.20944/preprints202309.1584.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: Synechococcus; silver nanoparticles; biogenic; antibacterial agents
Online: 25 September 2023 (05:36:58 CEST)
Abstract: Given the increasing resistance of some bacterial strains to many common antibiotics used in the local market, the current study aimed to produce nanoscale particles capable of combating pathogenic bacteria that have developed resistance to current antibiotics. In this research, an ex-perimental study was conducted to produce nanoscale particles using the single-celled blue-green algae Synechococcus sp., which was isolated from a local environment in the Arab Republic of Egypt, specifically from a soil sample in Beni-Suef City. The aim of the study was to generate silver NPs employing different biological approaches, encompassing the direct strain powder technique, ethanol extract pellet technique, and ethanol extract technique. These synthesized nanoparticles displayed different shapes, including cubic, spherical, pellet-like, and rod-shaped particles. They were characterized by bio-functional groups containing Ag+ ions, which were detected using FT-IR, Zeta sizer, and Zeta potential measurements. High-resolution SEM imaging unveiled the mor-phological features of Silver NPs with biologically formed protective layers, spanning sizes from 20 to 430 nm for individual particles. The study evaluated the antibacterial efficiency against both G+ve and G-ve bacteria. The ethanolic extract technique exhibited the largest inhibition zone (24 mm) against G+ve bacteria, particularly Staphy. aureus. Furthermore, it was observed that the larger particles produced using the powder and pellet techniques were less effective antibacterial agents. In conclusion, this investigation emphasizes the potential of cyanobacteria-based synthesis of silver nanoparticles as a promising approach for producing innovative antimicrobial agents.
ARTICLE | doi:10.20944/preprints202305.2198.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: Curcumin longa; Zinc oxide; Antibacterial; nanoparticles
Online: 31 May 2023 (08:23:20 CEST)
Incorporating nanoparticles into plant cultivation has been shown to improve growth parameters and alter the bioactive component compositions of many plant species, including Curcumin longa. The aim of the current study was to investigate the effects of foliar application of zinc oxide na-noparticles on the content of bioactive compounds and their antibacterial activities against poten-tial bacterial pathogens. To this end, C. longa leaves were treated with different doses of ZnO NPs to see how they affected bioactive component composition. The effect of different doses of ZnO NPs on the accumulation of bisdemethoxycurcumin, demethoxycurcumin, and curcumin in etha-nolic extracts of C. longa rhizomes was evaluated using high-performance liquid chromatography (HPLC). When compared to the control treatment, foliar spraying with (5 and 40 mgL-1) ZnO NPs increased bisdemethoxycurcumin, demethoxycurcumin, and curcumin levels by approximately (2.69 and 2.84), (2.61 and 3.22), and (2.90 and 3.45) fold, respectively. It was looked at to see if the ethanolic extracts made from the plantlets might change in terms of their phytochemical makeup and antibacterial properties. Furthermore, the results revealed that C. long-ZnO-NPs displayed antibacterial activity against S. aureus and P. aeruginosa tested bacterium strains, but made little attempt against E. coli. The MIC for P. aeruginosa was 100 g/mL. Time-kill studies also revealed that ZnO-NPs at 4 MIC killed P. aeruginosa, Actinobacteria baumannii, and Bacillus sp. after 2 hours, while S. aureus did not grow when treated with 4xMIC of the extract for 6 hours. The strongest antibacterial activity was seen with extract from plantlets grown without nanoparticles for P. aeruginosa, whereas it was seen with extract from plantlets grown in the presence of 5 mg/L ZnO-NPs for E. coli, S. aureus, and P. aeruginosa. These findings show that ZnO-NPs are a pow-erful enhancer of bioactive compound production in C. longa, a trait that can be used to combat antibiotic resistance in pathogenic bacterial species.
REVIEW | doi:10.20944/preprints202304.1124.v2
Subject: Chemistry And Materials Science, Other Keywords: copper coordination; copper homeostasis; antibacterial; antibiotic
Online: 23 May 2023 (08:01:12 CEST)
Classical antibacterial drugs were designed to target specific bacterial properties distinct from host human cells to maximize potency and selectivity. These designs were quite effective as they could be easily derivatized to bear next generation drugs. However, the rapid mutation of bacteria and their associated acquired drug resistance have led to the rise of highly pathogenic superbug bacterial strains for which treatment with first line drugs is no match. More than ever, there is a dire need for antibacterial drug design that goes beyond conventional standards. Taking inspiration by the body’s innate immune response to employ its own supply of labile copper ions in a toxic attack against pathogenic bacteria, which have a very low Cu tolerance, this review article examines the feasibility of Cu-centric strategies for antibacterial preventative and therapeutic applications. Promising results are shown for the use of Cu-containing materials in the hospital setting to minimize patient bacterial infections. Studies directed at disrupting bacterial Cu regulatory pathways elucidate new drug targets that can enable toxic increase of Cu levels and perturb bacterial dependence on iron. Likewise, Cu intracellular chelation/prochelation strategies effectively induce bacterial Cu toxicity. Cu-based small molecules and nanoparticles demonstrate the importance of the Cu ions in their mechanism and display potential synergism with classical drugs.
ARTICLE | doi:10.20944/preprints202210.0166.v1
Subject: Medicine And Pharmacology, Dentistry And Oral Surgery Keywords: antibacterial photodynamic therapy; Oral hygiene; Periodontitis
Online: 12 October 2022 (08:59:58 CEST)
A single-site, randomized clinical trial was designed to determine the efficacy of regular home use of Lumoral® dual-light antibacterial aPDT in periodontitis patients. For the study, 200 patients are randomized to receive non-surgical periodontal treatment (NSPT), including standardized hygiene instructions and electric toothbrush, and scaling and root planing, or NSPT with adjunctive Lumoral® treatment. A complete clinical intraoral examination is conducted in the beginning, at three months, and at six months. This report presents the three-month results of the first 59 consecutive randomized subjects. At three months, bleeding on probing (BoP) was lower in the NSPT+Lumoral®-group than in the NSPT group (p=0.045), and more patients in the NSPT+Lumoral®-group had their BoP below 10% (52% vs. 29%, respectively, p=0.008). Patients in the NSPT+Lumoral®-group improved their oral hygiene by visible-plaque-index (p=0.0002), while the NSPT group showed no statistical improvement as compared to baseline. Both groups significantly reduced the number of deep periodontal pockets, but more patients with a reduction in their deep pocket number were found in the NSPT+Lumoral® group (92% vs. 63%, p=0.01). Patients whose number of deep pockets was reduced by 50% or more were also more frequent in the NSPT+Lumoral®-group (70% vs. 33%, p=0.01). Patients with initially less than ten deep pockets had fewer deep pockets at three-month follow-up in the Lumoral® group (p=0.02). In conclusion, adjunctive use of Lumoral® in NSPT results in improved treatment outcomes at three months post-therapy.
ARTICLE | doi:10.20944/preprints202207.0264.v1
Subject: Chemistry And Materials Science, Surfaces, Coatings And Films Keywords: antibacterial; biomedical implants; electrophoretic deposition; osteogenesis
Online: 18 July 2022 (10:24:35 CEST)
Implants are used to replace damaged biological structures in human body. Although stain-less-steel (SS) is a well-known implant material, corrosion of SS implants led to the release toxic metallic ions which produce harmful effects in human body. To prevent material degradation and its harmful repercussions, these implanted materials are subjected to biocompatible coatings. Polymeric coatings play a vital role in enhancing the mechanical and biological integrity of the implanted devices. Zein is a natural protein extracted from corn and is known to have good bio-compatibility and biodegradability. In this study, Zein/Ag-Sr doped mesoporous bioactive glass nanoparticles (Ag-Sr MBGNs) were deposited on SS substrates via electrophoretic deposition (EPD) at different parameters. Ag and Sr ions were added to impart antibacterial and osteogenic properties to the coatings, respectively. In order to examine the surface morphology of coatings, optical microscopy and scanning electron microscopy (SEM) were performed. To analyze me-chanical strength, pencil scratch test, bend test, corrosion and wear tests were conducted on ze-in/Ag-Sr doped MBGNs coatings. The results show good adhesion strength, wettability, corro-sion, and wear resistance for zein/Ag-Sr doped MBGNs coatings as compared to bare SS sub-strate. Thus, good mechanical and biological properties were observed for zein/Ag-Sr doped MBGNs coatings. Results suggested these zein/Ag-Sr MBGNs coatings have great potential in bone regeneration applications.
REVIEW | doi:10.20944/preprints202204.0142.v1
Subject: Chemistry And Materials Science, Biomaterials Keywords: metallic ions; biomedical; antibacterial; osteoporosis; therapeutic
Online: 15 April 2022 (10:27:18 CEST)
This review focuses on the therapeutic effects of metallic ions when released in physiological environments. Recent studies have shown that metallic ions like Ag+, Sr2+, Mg2+, Mn2+, Cu2+, Ca2+, P+5, etc., have shown promising results in drug delivery systems and regenerative medicine. These metallic ions can be loaded in nanoparticles, mesoporous bioactive glass nanoparticles (MBGNs), hydroxyapatite (HA), calcium phosphates, polymeric coatings, and salt solutions. The metallic ions can exhibit different functions in the physiological environment such as antibacterial, antiviral, anti-cancer, bioactive, biocompatible, and angiogenic effect. Furthermore, the metallic ions can be loaded in scaffolds to improve osteoblast proliferation, differentiation, bone development, fibroblast growth, and improved wound healing efficacy. Moreover, different metallic ions possess different therapeutic limits. Therefore, further mechanisms need to be developed for the highly controlled and sustained release of these ions. This review paper summarizes the recent progress in the use of metallic ions in regenerative medicine and encourages further study of metallic ions as a solution to cure diseases.
ARTICLE | doi:10.20944/preprints202110.0308.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Salmonella newington; ɛ34 phage; Lipopolysaccharides; Antibacterial
Online: 21 October 2021 (12:47:13 CEST)
Salmonella can cause acute and chronic infections in humans. Salmonella species are known to cause food poisoning and other diseases in developing countries. Their role in the pathogenesis of these diseases has received increased international attention. Despite numerous advances in sanitation, they still can infect humans and cause outbreaks in developed countries. For example, Salmonella causes about 1.2 million illnesses in the US each year with over 450 deaths. Additionally, Salmonella outbreaks cause significant losses to chicken producers globally. The Salmonella species is also prone to acquiring resistance to various classes of antibiotics. Hence, the need for a paradigm shift from antibiotics to bacteriophages to manage, control and treat bacterial infections. The ɛ34 phage belongs to Podoviruses and categorized into the P22-like phages. The P22-like phages include ɛ34, ES18, P22, ST104, and ST64T. In this work, we investigated the antibacterial property of ɛ34 phage tailspike protein against Salmonella newington (S. newington). We demonstrate here that, the phage’s tailspike protein enzymatic property as a LPS hydrolase synergizes with Vero Cell culture supernatant in killing S. newington. Using decellularized cartilage scaffold as an ex vivo tissue model, the ɛ34 TSP protected the scaffold from S. newington biofilm formation. Computational analysis of the ɛ34 TSP interaction with membrane proteins of S. newington demonstrated a higher probability (0.7318) of binding to ompA of S. newington, and when docked to ompA extracellular component, it produced a high free energy of -11.3kcal/mol. We also demonstrate the resistance/sensitivity of the tailspike to the digestive enzyme trypsin. The data obtained in this work indicates that the trypsin resistant tailspike protein of Ɛ34 phage can be formulated as a novel antibacterial agent against S. newington.
ARTICLE | doi:10.20944/preprints202312.0343.v1
Subject: Environmental And Earth Sciences, Other Keywords: Chinese fir; species; wound exudate; antibacterial effect
Online: 6 December 2023 (12:40:51 CET)
To reveal the antibacterial effect of wound secretions of different Chinese fir strains on five kinds of bacteria. Three 3-year-old seedlings of Taxus chinensis var.koraiensis and Yangkou and the 3-year-old container seedlings of Taxus chinensis var.pendula, Yang061 and Yang020, were used as the research objects. The antibacterial effect of wound secretions was determined by the filter paper diffusion method, and the antibacterial effect was analyzed. Results showed that the wound secretions of different strains of Chinese fir bark had noticeable bacteriostatic effects on Bacillus subtilis, Salmonella paratyphi B, Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus aureus. However, the bacteriostatic effects of different strains of Chinese fir secretions differed. The minimum inhibitory concentrations (MICs) of the wound secretions of different strains of Chinese fir against the five test bacteria differed. The mean MIC of Pseudomonas aeruginosa was the highest, and the mean MIC of Escherichia coli was the lowest. The antibacterial ability of the wound secretions of different Chinese fir strains was mainly determined by the composition of the wound secretions. There was no noticeable relationship with the number of wound secretions.
ARTICLE | doi:10.20944/preprints202309.1246.v1
Subject: Chemistry And Materials Science, Organic Chemistry Keywords: DDSs; Metal Nanoparticle; Antibacterial; Omeprazole; Omeprazole sulfide
Online: 19 September 2023 (15:28:46 CEST)
At this time, nanoparticles used to been considered for various biomedical applications due to their particular properties[1, 2]. It is already known that one of the major advances in the relative application of nanoparticles is the recognition of the steric stabilization which can increase the particle stability in the biological environment and provide the opportunities of the application of nanoparticles in the development of drug delivery systems (DDSs) for achieving drug targeting and controlled drug release. Nano crystalline silver particles (AgNPs) have major applications in biomolecular recognition of highly sensitive, anti-microbial treatment, catalysis and manufacture sensors [3-7]. The NPs for various applications medical like image quality, medicine, tissue, magnetic resonance imaging (MRI) of targeting tissues and cells styles. This is particularly the case of AgNPs significantly encompasses the whole a wide range of industrial and medical applications. In this study, we have been synthesized incorporated omeprazole and omeprazole sulfide drugs with AgNPs and the results was investigated with TEM, FT-IR, DRS and XRD. The particle size has been seen in imaging TEM about 80 nm. Moreover either Omeprazole@AgNPs or omeprazole sulfide@AgNPs are able to excrete bacteria. In this study, the antibacterial properties of drugs with silver nanoparticles also increased.
ARTICLE | doi:10.20944/preprints202309.0122.v1
Subject: Medicine And Pharmacology, Medicine And Pharmacology Keywords: Hydroxamic acids; Antibacterial; Anti-biofilm; Mycobacterium tuberculosis
Online: 4 September 2023 (15:33:31 CEST)
Hydroxamic acid (HA) derivates displayed antibacterial and antifungal activities. HA with various numbers of carbon atoms (C2, C6, C8, C10, C12 and C17), complexed to different metal ions Fe(II/III), Ni(II), Cu(II) and Zn(II) were evaluated for their antimycobacterial activities and their anti-biofilm activities. Some derivates, among others HA12Fe2, inhibited the development of Mycobacterium tuberculosis, Mycobacterium bovis BCG and Mycobacterium marinum biofilms and could even attack pre-formed Pseudomonas aeruginosa biofilm. Proteomic profiles showed that the potential targets of HA10FeCl were mainly related to mycobacteria stress adaptation, involving cell wall lipid biosynthesis, drug resistance and tolerance, siderophore metabolism. This study provides new insights regarding the antimycobacterial activities of the HA and their complexes, especially about their potential antibiofilm activities.
ARTICLE | doi:10.20944/preprints202308.1898.v1
Subject: Chemistry And Materials Science, Materials Science And Technology Keywords: 4B2MBN; FT-IR; FT-Raman; Photoluminescence; Antibacterial
Online: 29 August 2023 (03:43:33 CEST)
By slowly evaporating 4-bromo-2-methylbenzonitrile at room temperature, it was possible to make a single organic nonlinear optical crystal. The grown crystal's crystalline nature was verified, and the unit cell characteristics are provided as a = 4.08Å, b = 6.61 Å, c = 28.93Å, α = 90º, β = 90º, γ = 90º. The functional groups of the crystal produced were identified using the FTIR and FT-Raman spectra. The UV cutoff wavelength is found at 221.6 nm, and the transparency nature of the crystal was analyzed in the optical studies. The band gap of the grown crystal was estimated using the Taucs’ plot. The violet and red emissions of photoluminescence are discussed. A high dielectric constant was received at a low frequency. The TG/DTA curve shows that the grown crystal was stable up to 125.59 ºC. The Kurtz-Perry powder technique was applied to confirm the Second Harmonic Generation's (SHG) nature. By using the agar diffusion method, the antibacterial property of the grown 4B2MBN crystal was determined.
ARTICLE | doi:10.20944/preprints202308.1180.v1
Subject: Chemistry And Materials Science, Surfaces, Coatings And Films Keywords: antibacterial activity; orthodontic archwires; Streptococcus mutans; nanocoatings
Online: 16 August 2023 (10:45:25 CEST)
Background: The use of nitinol (NiTi) archwires in orthodontic treatment has expanded significantly due to unique mechanical properties. The greatest barrier to safe orthodontic treatment is chemically or microbiologically induced corrosion, resulting in Ni2+ release. The aim of this investigation was to enhance corrosion resistance and introduction antibacterial properties to NiTi archwire by coating them with TiN-Cu. Methods: NiTi archwires were coated with TiN-Cu using cathodic arc evaporation and direct current magnetron sputtering. The morphology of the sample was analyzed by FESEM and the chemical composition was assessed using EDS, XRD and FTIR. Inductively coupled plasma-optical emission spectrometry was used to estimate the ion release. Biocompatibility of samples was investigated using MTT test. Antibacterial activity was analyzed against Streptococcus mutans and Streptococcus mitis. Results: Physico-chemical characterization revealed well-designed coatings with the presence of TiN phase with incorporated Cu2+. TiN-Cu coated archwires showed statistically lower Ni2+ release (p<0.05). Relative cell viability was the highest regarding 28-day eluates of TiN-Cu coated archwires (p<0.05). The most remarkable decrease in Streptococcus mitis concentrations was observed in case of TiN-Cu coated archwires (p<0.05). Conclusion: Taking into account biocompatibility and antibacterial tests, TiN-Cu coated archwires may be considered as a good candidate further clinical investigations.
ARTICLE | doi:10.20944/preprints202307.1996.v1
Subject: Chemistry And Materials Science, Medicinal Chemistry Keywords: soft coral; Lobophytum sp.; steroids; antibacterial activity
Online: 28 July 2023 (11:41:26 CEST)
Chemical investigation of the Chinese soft coral Lobophytum sp. has resulted in the isolation of six new compounds, namely lobosteroids A–F (1–6), along with four known compounds. Their structures were determined by extensive spectroscopic analysis and comparison with the spectral data reported in the literature. Among them, the absolute configuration of 1 was determined by X-ray diffraction analysis. These steroids characterized by either the presence of an α,β-αꞌ,βꞌ-unsaturated carbonyl or an α,β-unsaturated carbonyl moiety in ring A, or the existence of a 5α,8α-epidioxy system in ring B, as well as diverse oxidation sites of side chains. The prelimi-nary antibacterial bioassay showed all compounds exhibited significant antibacterial activities against the fish pathogenic bacteria Streptococcus parauberis FP KSP28 and Phoyobacterium damselae FP2244 with all inhibition rates more than 90% at the concentration of 150 µM. And at the same concentration, compounds 2, 6–10 also displayed potent inhibitory effects against vancomy-cin-resistant Enterococcus faecium bacteria G7 with all inhibition rates more than 90%.
ARTICLE | doi:10.20944/preprints202307.0734.v1
Subject: Chemistry And Materials Science, Nanotechnology Keywords: green method; copper oxide nanoparticles; antibacterial; ultrastructure
Online: 11 July 2023 (12:37:34 CEST)
Copper oxide nanoparticles (CuONPs) were synthesized using an eco-friendly method and their antimicrobial and biocompatibility properties were determined. The supernatant and extract of the fungus Ganoderma sessile yielded small, quasi-spherical NPs with an average size of 4.5 ± 1.9 nm and 5.2 ± 2.1 nm, respectively. CuONPs showed antimicrobial activity against Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. Minimum inhibitory concentration (MIC) for E. coli and S. aureus was 15.9 µg/mL for nanoparticles (NPs) using the supernatant (CuONPs-S) and 16.5 µg/ml for NPs using the extract (CuONPs-E). Lower concentrations were required for P. aeruginosa inhibition. Ultrastructural analysis revealed the presence of the small CuONPs all through the bacterial cells. Finally, the toxicity of CuONPs was analyzed in three mammalian cell lines: hepatocytes (AML-12), macrophages (RAW 264.7) and kidney (MDCK). Low concentrations (<15 µg/ml) of CuONPs-E were non-toxic to kidney cells and macrophages, and the hepatocytes were the most susceptible to CuONPs-S. The results obtained suggest that the CuONPs synthesized using the extract of the fungus G. sessile, could be further evaluated for the treatment of superficial infectious diseases.
ARTICLE | doi:10.20944/preprints202306.0308.v1
Subject: Chemistry And Materials Science, Biomaterials Keywords: Wound healing; Antibacterial; Hydrogel; Meshfill; Silver nanocomposite
Online: 5 June 2023 (10:34:40 CEST)
Introduction: Among the many factors that may limit effective wound healing in patients with chronic ulcers, bacterial infection and poor cell recruitment are primary causes that contribute to prolonged healing. Thus, a novel strategy that aims to prevent bacterial infection within the wound, while at the same time providing structural scaffolding that promotes endogenous tissue repair, would be of great interest. Here, we developed a thermo-sensitive silver nanoparticle hydrogel composite as an antibacterial nutritional scaffold for the wound that contains all nutrients required for cell growth while preventing bacterial infection with the ability to fill up all the cavities and void areas in wounds regardless of their geometry. Methods: Silver nanoparticles (AgNPs) were synthesized by chemical reduction. After characterization, silver hydrogel nanocomposite was developed by reconstitution of collagen-based hydrogel powder in a nanoparticle suspension of varying AgNPs concentrations (200, 400, and 600 ppm). The antibacterial activity of the formulations was examined in vitro and in vivo in subcutaneous implant infected model. The wound healing efficacy of the hydrogel nanocomposite was also evaluated using a splinted wound model in rats through comparison of clinical wound measurements and histological assessments. Cytocompatibility assay and biochemical analysis of blood at the end of in vivo wound healing study were performed to evaluate the safety of formulations. Results: The synthesized nanoparticles were spherical and stable. While hydrogel alone did not show any bacterial reduction in vitro, the inhibition of bacterial growth was significant in all silver hydrogel nanocomposites compared to controls (p <0.05) and was dose-dependent, with maximum reduction observed in the 600 ppm group (4.56±0.26 LOG CFU/mL, P<0.001). All concentrations of AgNPs hydrogel composites showed significant antibacterial activity in vivo as well (P<0.0001). Treatment of splinted wounds with AgNPs hydrogel composite resulted in faster wound closure and accelerated wound re-epithelialization. The formulations were non-cytotoxic and did not differ significantly in hematological and biochemical factors from the control group in in vivo study. Conclusions: By presenting promising antibacterial and wound healing activity, silver hydrogel nanocomposite offers a safe therapeutic option that can be used as a functional scaffold for an acceleration of wound healing.
ARTICLE | doi:10.20944/preprints202305.1651.v1
Subject: Chemistry And Materials Science, Biomaterials Keywords: Chitosan, Fibres, Ursolic acid, antibacterial, Chitosan Fibres.
Online: 23 May 2023 (11:07:17 CEST)
Over the years, chitosan has been the subject of numerous studies and has gained significant popularity as a biomaterial due to its various characteristics, including biocompatibility, biodegradability, and bioactivity. In this work, chitosan fibres surface was modified with ursolic acid to improve their antibacterial properties by wet impregnation method. Five specimens of chitosan fibres were immersed in ursolic acid (UA) solution for varying immersion times of 1, 2, 4, 6, and 8 hours. Characterization was carried out by means of FTIR, SEM, UV-Vis spectroscopy; the results indicated an ongoing chemical reaction between chitosan and ursolic acid resulting in changes to the chemical structure. After 2 hours, the absorbance ratio remained constant; suggesting that the reaction had reached completion and the chemical structure of the sample remained stable. Antibacterial tests were performed on the resulting chitosan fibres against two bacterial strains. The fibres without ursolic acid did not exhibit any noteworthy antibacterial activity against either strain. However, the chitosan fibres modified with ursolic acid showed significant and almost strong antibacterial activity against the Gram-positive strain, S. aureus. These results suggest that chitosan fibres modified with ursolic acid could have potential applications as antibacterial materials, particularly against Gram-positive bacteria.
ARTICLE | doi:10.20944/preprints202304.1065.v1
Subject: Chemistry And Materials Science, Surfaces, Coatings And Films Keywords: jade waste; antibacterial agent; activation temperature; coatings
Online: 27 April 2023 (09:53:36 CEST)
Jade waste is a normal byproduct that makes up much more than the amount of jade extracted. Therefore, recycling jade waste is worth investigating from the point of view of energy conservation. Moreover, it is an environment-friendly material, which is desirable for use in building materials. In this study, Xiuyan jade waste was repurposed as antibacterial additives for building coatings. The powder waste was activated by milling and subsequent annealing. The antibacterial properties of the treated waste were mostly related to the annealing temperatures. Based on the investigations of the phase change and the release of metal ions of a series of samples and their antibacterial activities, the antibacterial mechanism of the treated samples was explored experimentally. The most applicable sample for coatings was finally chosen by considering its pH values and its antibacterial abilities. Antibacterial testing showed that the addition of treated jade waste could enhance the bacterial inhibition rate of building coatings from 60% to 99.9%.
COMMUNICATION | doi:10.20944/preprints202301.0364.v1
Subject: Chemistry And Materials Science, Applied Chemistry Keywords: polycation; polydiallyldimethylammonium chloride; polymer coating; antibacterial coatings
Online: 19 January 2023 (13:07:33 CET)
Biocidal compositions based on interpolyelectrolyte complexes and a low molecular weight antibiotic can become a promising material for creating biocidal coatings, as they combine wash-off resistance and dual biocidal action due to the biocide and the polycation. Molecular mass characteristics of polymers play essential role in physics and mechanical properties of the coatings. In this work, the properties of polydiallyldimethylammonium chloride (PDADMAC) coatings of various molecular weights are investigated and assumptions are made about the optimal molecular weight needed to create antibacterial compositions. To study the resistance to washing off and moisture saturation of the coatings, the gravimetric method was used, the adhesive properties of the coatings were studied by dynamometry. It has been established that an increase in molecular weight affects the wash-off resistance of coatings, but does not affect moisture absorption and adhesion mechanics of coatings. All samples of PDADMAC were demonstrated to exhibit the same antibacterial activity. Thus, when developing systems for creating antibacterial coatings, it must be taken into account that in order to create stable coatings. The requirement to use PDADMAC with a high degree of polymerization is necessary for control the desorption of coating during wash off-but not mandatory for the control of mechanical and antibacterial properties of the coating.
ARTICLE | doi:10.20944/preprints202109.0311.v1
Subject: Chemistry And Materials Science, Organic Chemistry Keywords: Quinazolinone; Styrene; Methacrylate; Nano-silver; Antibacterial; Antitumor.
Online: 17 September 2021 (12:11:48 CEST)
Reaction of 2-mercapto-3-phenylquinazolin-4(3H)-one (MPQ) with both 4-vinyl benzyl chloride and allyl bromide furnished the reactive heterocyclic monomers 3-phenyl-2-((4-vinylbenzyl) thio) quinazolin-4(3H)-one (PVTQ) and 2-(allylthio)-3-phenylquinazolin-4(3H)-one (APQ), respectively. Copolymerization of PVTQ monomer with styrene and methyl methacrylate in the presence of 2,2′-azobisisobutyronitrile (AIBN) afforded the copolymers PS-co-PPVTQ and PMMA-co-PPVTQ, respectively. Similarly, copolymerization of monomer APQ with styrene and methyl methacrylate (MMA) afforded the copolymers PS-co-PAPQ and PMMA-co-PAPQ, respectively. The resulted copolymers were characterized by using FT-IR, 1H-NMR and GPC techniques. Silver nanocomposites of PS, PMMA, PS-co-PPVTQ, PMMA-co-PPVTQ, PS-co-PAPQ and PMMA-co-PAPQ were synthesized by the addition of silver nitrate into the polymer solution. The reduction of silver ions into silver nanoparticles was performed in DMF and water. Thermogravimetric (TGA) analysis was used to determine the thermal stability of the copolymers and their silver nanocomposites. The X-ray diffraction (XRD) analysis indicated the amorphous structures of the co-polymers and confirmed the formation of silver nanoparticles. The antitumor and antibacterial activities were screened for the copolymers and enhanced by the formation of their silver nanocomposites. In vivo antitumor activity in Ehrlich Ascitic Carcinoma (EAC) mice model showed that PS-co-PPVTQ/Ag NPs, PMMA-co-PPVTQ/Ag NPs, and PMMA-co-PAPQ/Ag NPs displayed promising inhibitory effects against EAC and induce apoptosis against MCF-7 cells.
ARTICLE | doi:10.20944/preprints202010.0077.v1
Subject: Chemistry And Materials Science, Analytical Chemistry Keywords: acetamide; pyridine; pyrrolidine; piperidine; antibacterial activity; heterocycles
Online: 5 October 2020 (11:51:12 CEST)
A sequence of new acetamide derivatives 9-15 of primary, secondary amine, and para-toluene sulphinate sodium salt have been synthesized under microwave irradiation and assessed in vitro for their antibacterial activity against one Gram-positive and two Gram-negative bacterial species such as S. pyogenes, E. coli, and P.mirabilis using the Mueller-Hinton Agar diffusion (well diffusion) method. The synthesized compounds with significant differences in inhibition diameters and MICs were compared with those of amoxicillin, ampicillin, cephalothin, azithromycin and doxycycline. All of the evaluated acetamide derivatives were used with varying inhibition concentrations of 6.25, 12.5, 37.5, 62.5, 87.5, 112.5 and 125 µg/ml. The results show that the most important antibacterial properties exercised by the synthetic compounds 9 and 11 bearing para-chlorophenyl moiety incorporated into the 2-position moiety of acetamide 2. The molecular structures of the new compounds were determined using FT-IR, 1H-NMR techniques.
ARTICLE | doi:10.20944/preprints202003.0263.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: pectin; antibacterial; lemon; flavonoids; hydrodynamic cavitation; IntegroPectin
Online: 17 March 2020 (03:43:39 CET)
Pectin extracted via hydrodynamic cavitation in water only from waste lemon peel and further isolated via freeze drying displays significant antibacterial activity against Staphylococcus aureus, a Gram positive pathogen which easily contaminates food. The antibacterial effect of the new IntegroPectin is largely superior to that of commercial citrus pectin, opening the way to advanced applications of a new bioproduct now obtainable in large amounts and at low cost from citrus juice industry’s waste.
ARTICLE | doi:10.20944/preprints201902.0248.v1
Subject: Chemistry And Materials Science, Medicinal Chemistry Keywords: 10-methoxycanthin-6-one; quaternization; antibacterial; SARs
Online: 27 February 2019 (05:08:02 CET)
Natural products are an important source of antibacterial agents. Canthin-6-one alkaloids have displayed potential antibacterial activity based on our previous work. In order to improve the activity, twenty-two new 3-N-benzylated 10-methoxy canthin-6-ones were designed and synthesized through quaternization reaction. The in vitro antibacterial activity against three bacteria was evaluated by double dilution method. Four compounds (6f, 6i, 6p and 6t) displayed 2-fold superiority (minimum inhibitory concentration (MIC) = 3.91 µg/mL) against agricultural pathogenic bacteria R. solanacearum and P. syringae than agrochemical propineb. Moreover, the structure–activity relationships (SARs) were also carefully summarized in order to guide the development of antibacterial canthin-6-one agents.
ARTICLE | doi:10.20944/preprints201901.0127.v1
Subject: Chemistry And Materials Science, Nanotechnology Keywords: metal nanoparticles; laser ablation; antibacterial test; LSPR
Online: 14 January 2019 (07:21:21 CET)
We report the production of metal oxide (TiFe2O4, ZnFe2O4) nanoparticles by pulsed laser ablation technique in liquid environment. We used nano second Nd: YAG laser systems working at 532 nm and 1064 nm of wavelength, the energy of the laser beam was kept constant at 80 mJ. Absorbance spectra, surface plasmon resonance, optical band-gap and nanoparticle morphology were investigated using ultraviolet-visible (UV-Vis) spectroscopy, Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). Changing the wavelength of the laser for growth, nanoparticles shown shift between the absorbance and surface plasmon resonance peaks in their UV-Vis spectra, this implies that the optical properties of the colloid nanoparticles depends on laser parameters, this was confirmed with the variation of the band gap energy. Furthermore, red shift for the absorbance peak was observed for samples as-growth at 532 nm around the 150 nm as function of time preparation. Whereas, for the samples as-growth at 1064 nm there is no shift in the absorbance spectra, this can be due to agglomeration and formation of larger particles. The characterization results shown appropriate plasmonic photo-catalysts properties of the particles, hence the photo activation of the nanoparticles was examined on antibacterial effect using colonies of Staphylococcus Aureus and Escherichia coli.
ARTICLE | doi:10.20944/preprints201808.0528.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: Antibacterial, Linezolid, SARs, Alaninyl-oxazolidinone, Triazolyl-oxazolidinone
Online: 30 August 2018 (14:35:03 CEST)
Bacterial resistance towards existing class of antibacterial drugs continues to increase posing significant threat to clinical usefulness of these drugs. This increasing and alarming rates of antibacterial resistance development and the decline in the number of new antibacterial drugs approval continue to serve as major impetus for research into discovery and development of new antibacterial agents. We synthesized a series D-/L-alaninyl substituted triazolyl oxazolidinone derivatives and evaluated their antibacterial activity against selected standard Gram-positive and Gram-negative bacterial strains. Overall, the compounds showed moderate to strong antibacterial activity. Compounds 9d and 10d (D- and L-alaninyl derivatives bearing 3,5-dinitrobenzoyl substituent), 10e (D-alaninyl derivative bearing 5-nitrofurancarbonyl group) and 9f and 10f (D- and L-alaninyl derivatives bearing 5-nitrothiophene carbonyl moiety) demonstrated antibacterial activity (MIC:2 g/mL) against S. aureus, S. epidermidis, E. faecalis and M. catarrhalis standard bacterial strains. No significant differences were noticeable between the antibacterial activity of the D- and L-alaninyl derivatives as a result of the stereochemistry of the compounds.
ARTICLE | doi:10.20944/preprints201808.0253.v1
Subject: Chemistry And Materials Science, Biomaterials Keywords: graphene; silver nanoparticles; PHA; electrospun biomaterial; antibacterial
Online: 14 August 2018 (14:16:21 CEST)
Many wounds are unresponsive to current available treatment techniques and therefore there is an immense need to explore suitable materials including biomaterials, which are being considered as the crucial factor to accelerate the healing cascade. In this study, we fabricated polyhydroxyalkanoate based antibacterial mats via electrospun technique. One-pot green synthesized graphene decorated silver nanoparticles (GAg) were incorporated into the fibres of poly-3 hydroxybutarate-co-12 mol% hydroxyhexanoate (P3HB-co-12mol% HHx), a co-polymer of polyhydroxyalkanoate (PHA) family which is highly biocompatible, biodegradable and flexible in nature. The synthesised PHA/GAg biomaterial was characterized by field emission scanning electron microscopy (FESEM), elemental mapping, thermogravimetric analysis (TGA), UV-visible spectroscopy (UV-vis) and Fourier transform infrared spectroscopy (FTIR). In-vitro antibacterial analysis were performed to investigate the efficacy of PHA/GAg against gram positive Staphylococcus aureus (S.aureus) strain 12600 ATCC and gram negative Escherichia coli (E.coli) strain 8739 ATCC. The results indicated that the PHA/GAg demonstrated significant reduction of Staphylococcus aureus (S.aureus strain 12600 ATCC) and Escherichia coli (E.coli strain 8739 ATCC) as compared to bare PHA or PHA-rGO in 2 hours of time. The P value (P< 0.05) was obtained by using 2 sample T-test distribution.
ARTICLE | doi:10.20944/preprints202312.0509.v1
Subject: Biology And Life Sciences, Plant Sciences Keywords: Magnolia; polyphenols; phenolic compounds; volatile compounds; antibacterial activity
Online: 7 December 2023 (10:10:56 CET)
This research focuses on exploring the bioactive and antibacterial properties of extracts from the flowers and bark of four Magnolia species (Magnolia champaca, Magnolia denudata, Magnolia grandiflora, and Magnolia officinalis) for possible cosmetic applications. We used ethanol to extract compounds from these plants and conducted various tests including spectrophotometry, HPLC, GC-MS, and microbiological analyses. The extracts, particularly rich in polyphenols (55.18 mg GAE/g), displayed significant antioxidant capabilities, with IC 50 values ranging between 9.99 mg/mL and 23.23 mg/mL. We quantified different compounds: phenolic acids (6.259 to 27.883 mg/g dry weight), aglycone flavonoids (61.224 to 135.788 mg/g dw), glycosidic flavonoids (17.265 to 57.961 mg/g dw), and lignans (150.071 to 374.902 mg/g dw). We identified 76 volatile compounds, predominantly oxygenated monoterpenes and sesquiterpene hydrocarbons, which contribute to the antibacterial effectiveness of the extracts. These extracts showed greater antibacterial activity against Gram-negative bacteria than Gram-positive bacteria. The diverse chemical compounds and their demonstrated activities suggest these extracts could be valuable in cosmetic, pharmaceutical, or food industries.
ARTICLE | doi:10.20944/preprints202310.1251.v1
Subject: Chemistry And Materials Science, Materials Science And Technology Keywords: Aerodramus fuciphagus; antibacterial properties; green synthesis; silver nanoparticles
Online: 20 October 2023 (03:46:55 CEST)
Researchers are increasingly focusing on green synthesis methods for silver nanoparticles due to their cost-effectiveness and reduced environmental impact. In this study, we utilized an edible bird's nest (EBN), a valuable economic resource, as the primary material for synthesizing silver nanoparticles using only water as the solvent. Metabolite profiling of the EBN extract was conducted using LC-QTOF-MS in positive mode (ESI+), revealing the presence of lipids, glycosides, peptides, polysaccharides, and disaccharides. Upon the addition of silver nitrate to the aqueous EBN extract, noticeable color changes from transparent to brown indicated the successful formation of AgNPs. Subsequent characterization of these silver nanoparticles involved UV-Visible spectroscopy, which revealed an absorption peak at 421 nm. Further characterization was carried out using Field Effect Scanning Electron Microscopy (FESEM), Attenuated Total Reflectance-Fourier Infrared (ATR-FTIR) spectroscopy, and Energy Dispersive X-Ray (EDX) analysis. The involvement of phenolic agents, proteins, and amino acids in reducing the silver particles was confirmed. The synthesized nanoparticles exhibited a crystalline nature, a spherical shape, and a particle size ranging from 10 to 20 nm. The presence of elemental silver was confirmed by a strong, intense peak around 3 keV in the EDX spectrum. To assess their potential, the antibacterial properties of the silver nanoparticles against Escherichia coli and Staphylococcus aureus were evaluated using the agar diffusion method.
ARTICLE | doi:10.20944/preprints202309.1128.v1
Subject: Biology And Life Sciences, Animal Science, Veterinary Science And Zoology Keywords: antibacterial efficacy; isobutyl-cyanoacrylate nanoparticles; rainbow trout; safety
Online: 18 September 2023 (08:45:17 CEST)
The upsurge in and havoc being wrecked by antibiotic resistant bacteria makes urgent the need for efficacious alternatives to antibiotics. This study assessed the antibacterial efficacy of two isobutyl-cyanoacrylate nanoparticles (iBCA-NPs), D6O and NP30, against major bacterial pathogens of fish. In vivo tests on rainbow trout were preceded by tests of in vitro minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). NP30 exhibited higher efficacy, but both iBCA-NPs demonstrated dose-dependent and species-specific in vitro antibacterial properties against the bacterial isolates. Generally, Gram-negative bacteria were more resistant to the iBCA-NPs. Streptococcus iniae, Tenacibaculum maritimum, and Photobacterium damselae were particularly sensitive to both iBCA-NPs. Orally administered to rainbow trout, the iBCA-NPs produced relative gain rate and survival rates comparable to the control (P > 0.05). Condition factor, hepatosomatic and viscerosomatic indices of fish were indifferentiable (P > 0.05) between the iBCA-NP groups and the control. The iBCA-NPs caused no alteration in stress, oxidative stress (superoxide dismutase, SOD), plasma complement titre, and lysozyme activity. The results of this study suggest that D60 and NP30 may contribute to reducing the amount of antibiotics and chemotherapeutic agents being used in aquaculture.
ARTICLE | doi:10.20944/preprints202305.1696.v1
Subject: Chemistry And Materials Science, Medicinal Chemistry Keywords: Soft coral; Klyxum molle; Diterpenoids; Stereochemistry; Antibacterial activity
Online: 24 May 2023 (05:00:56 CEST)
Fifteen new diterpenoids, namely xishaklyanes A-O (1-15), along with three known related ones (16-18), were isolated from the soft coral Klyxum molle collected from Xisha Islands, South China Sea. The stereochemistry of the new compounds were elucidated by a combination of detailed spectroscopic analyses, chemical syntheses, quantum chemical calculations and comparison with the reported data. The absolute configuration of compound 18 was established by the modified Mosher's method for the first time. In bioassay, some of these compounds exhibited considerable antibacterial activities on fish pathogenic bacteria, and compound 4 showed the most effective activity with MIC of 0.225 g/mL against Lactococcus garvieae.
REVIEW | doi:10.20944/preprints202305.1106.v1
Subject: Biology And Life Sciences, Life Sciences Keywords: photothermal-antimicrobials; antibacterial mechanisms; anti-biofilm; wound healing
Online: 16 May 2023 (05:40:58 CEST)
Rapid developing antimicrobial resistance due to broad antibiotic utilisation in healthcare and food industries and the non-availability of novel antibiotics represents one of the most critical public health issues worldwide. The current advances in nanotechnology allow new materials to address drug-resistant bacterial infections in specific, focused and biologically safe ways. The unique physicochemical properties, biocompatibility, and wide range of adaptability of nanomaterials that exhibit photothermal capability can be employed to develop the next generation of photothermally induced controllable hyperthermia as antibacterial nanoplatforms. Here, we review the current state-of-the-art in different functional classes of photothermal antibacterial nanomaterials and the strategies to optimise antimicrobial efficiency. The recent achievements and trends in developing photothermally active nanostructures, including plasmonic metals, semiconductor, carbon-based, and organic photothermal polymers, and antibacterial mechanisms of action, including anti-multidrug resistant bacteria and biofilms removal, will be discussed. Insights into mechanisms of the photothermal effect and various factors influencing photothermal antimicrobial performance, emphasising the structure–performance relationship, are discussed. We will examine the photothermal agents’ functionalisation for specific bacteria, effects of near-infrared light irradiation spectrum, or active photothermal materials for multimodal synergistic-based therapies to minimise side effects and maintain low cost. Most relevant applications are presented, such as anti-biofilm formation, biofilm penetration or ablation, and nanomaterial-based infected wound therapy. Practical antibacterial applications employing the photothermal antimicrobial agents, alone or in synergistic combination with other nanomaterials, are considered. Existing challenges and limitations in photothermal antimicrobial therapy and future perspectives are presented from the structure, function, safety, and clinical potential points of view.
REVIEW | doi:10.20944/preprints202304.0953.v1
Subject: Medicine And Pharmacology, Pharmacy Keywords: Antibacterial Agents; Antibiotics; Cyclodextrins; Inclusion Complex; Technology; Treatments
Online: 26 April 2023 (04:09:37 CEST)
Antibiotics have become a widely used drug classes worldwide. Its indiscriminate use in the clini-cal-hospital environment ended up causing antibiotic-resistance genes. Pharmaceutical technology is an essential ally for new formulation development in the antibacterial field. Cyclodextrins (CDs) are ap-proaches that can potentially improve the effectiveness of antibacterial drugs. Thus, this study aimed to review experimental models using CDs as inclusion complexes to improve antibacterial drugs’ physi-cochemical characteristics and biological activities. The review was carried out using the three online journals database PubMed, Scopus, and Embase, limited to Medical Subjects Headings Index. The search protocol was registered in the Open Science Framework database. The following terms and their com-binations were used: cyclodextrins and antibacterial agents in title or abstract, and a total of 1580 studies were identified in a period up to October 2022. Finally, 27 articles were selected for discussion in this review. The biological results reveal that the antibacterial effect of the compounds, complexed with CDs, was extensively improved when compared to the free drugs. CDs can improve the therapeutic effects of antibiotics, already existing on the market, natural products, and synthetic molecules. Therefore, these inclusion complexes using CDs increase the new pharmaceutical products development for clinical ap-plication.
ARTICLE | doi:10.20944/preprints202209.0128.v1
Subject: Chemistry And Materials Science, Biomaterials Keywords: Hydrogels; polymers; regeneration; antibacterial; drug release; garlic; alicin
Online: 9 September 2022 (03:56:12 CEST)
Hydrogels can provide instant relief to pain and facilitate the fast recovery of wounds. Currently the incorporation of medicinal herbs/plants in polymer matrix is being investigated due to their anti-bacterial and wound healing properties. Herein, we investigated the novel combination of chitosan (CS), chondroitin sulfate (CHI) and garlic (Gar) to synthesize hydrogels through freeze gelation process for faster wound healing and resistance to microbial growth at the wound surface. The synthesized hydrogels were characterized via Fourier transform infrared spectroscopy (FTIR), which confirmed the presence of relevant functional groups. The scanning electron microscopy (SEM) images exhibited the porous structure of the hydrogels, which is useful for the sustained release of Gar from the hydrogels. The synthesized hydrogels showed significant inhibition zones against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). Furthermore, cell culture studies confirmed the cyto-compatibility of the synthesized hydrogels. Thus, the novel hydrogels presented in this study can offer antibacterial effect during wound healing and promote tissue regeneration.
REVIEW | doi:10.20944/preprints202207.0040.v1
Subject: Medicine And Pharmacology, Pharmacology And Toxicology Keywords: Kalanchoe; antibacterial; anti-inflammatory properties; wound healing; antioxidant
Online: 4 July 2022 (08:27:24 CEST)
The Kalanchoe genus is composed of more than 100 species that usually thrive in tropical environments, which have been used in folkloric medicine to treat various illnesses, including dermatological conditions. With this, the present study assesses the pharmacognostical and pharmacological properties of different species of the Kalanchoe genus as elements for a potential treatment for dermatological-related conditions, from findings of existing literature and studies. It was analyzed that the Kalanchoe pinnata plant, or one of the most common species of Kalanchoe, have been observed to have distinct morphological and microscopic characteristics. Further, it was discovered that different species of Kalanchoe have anti-inflammatory, antioxidant, antibacterial, and wound healing properties, which enable the plant to be used for dermatological products that are available to the market. With this, it is recommended that further studies be conducted in other understudied species of Kalanchoe regarding their pharmacological properties, as well as the use of other structures of the Kalanchoe plant for treatment of various dermatological conditions.
ARTICLE | doi:10.20944/preprints202205.0118.v1
Subject: Chemistry And Materials Science, Physical Chemistry Keywords: magnetite; dopamine; surface modification; hybrid materials; antibacterial agents.
Online: 9 May 2022 (13:47:08 CEST)
Organically-coated nanomaterials are intensively studied and find numerous applications in a wide range of areas ranging from optics to biomedicine. One of the recent trends in material science is the application of bio-mimetic polydopamine coatings that can be produced on a variety of substrates in a cost-efficient way under mild conditions. Such coatings not only modify the biocompatibility of the material but also add functional amino groups to the surface that can be further modified by classic conjugation techniques. Here we show an alternative strategy of substrates modification using not dopamine but dopamine conjugates. Compared to the classic scheme the proposed strategy allows for separation of the "organic" and "colloidal" stages and simplifies identification and purification steps. Modification with pre-modified dopamine allowed to achieve high active components loading up to 10.5% wt. A series of organo-inorganic hybrids were synthesized and their bioactivity was analyzed.
ARTICLE | doi:10.20944/preprints202111.0155.v1
Subject: Chemistry And Materials Science, Biomaterials Keywords: nanomaterials; microarc oxidation; dextran; minocycline; titanium; antibacterial coating
Online: 8 November 2021 (15:10:53 CET)
Peri-implantitis occurs at a significant rate, which is the leading cause of implant failure. The main reason for this unwanted complication is bacterial invasion and biofilm formation. To reduce the incidence of peri-implantitis, we constructed a carboxymethyl dextran (CMD) based nanomicelles antibacterial coating on microarc-oxidized titanium (MAO-Ti) surface. After cross-linking, the drug-loaded nanomicelles were spherical with a particle size of 130nm and uniformly dispersed. Zeta potential was negative, and the absolute value was greater than 10 mV, effectively avoiding micelles aggregation. It was observed by dynamic light scattering (DLS) that the stability of nanomicelles was significantly improved after cross-linking. The hemolysis rate of micelles was less than 5%, and the overall survival rate of human umbilical vein endothelial cells was more than 90%. After being coated on MAO-Ti surface, the cumulative drug release rate of drug-loaded nanomicelles reached 86.6% after 360 hours. Fluorescence staining of immobilized bacteria showed more dead bacteria on the coating surface, and the number of live bacteria was significantly reduced. It was concluded that dextran-based nanomicelles, which showed long-term drug release properties and excellent biocompatibility, are potential drug carriers for fabricating antibacterial coating on titanium surfaces.
ARTICLE | doi:10.20944/preprints202103.0367.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: ultrasound; blue light; Biofilm; Propionibacterium acnes; bacteria; antibacterial
Online: 15 March 2021 (11:11:32 CET)
Abstract: Bacterial biofilms are highly resistant to antibiotics and have been implicated in the etiology of 60-80% of chronic microbial infections. We tested a novel combination of low intensity ultrasound and blue light against biofilm and planktonic bacteria. A laboratory prototype was built which produced both energies uniformly and coincidently from a single treatment head, impinging upon a 4.45 cm^2 target. To demonstrate proof of concept, Propionibacterium acnes biofilm was cultured on Millicell hanging inserts in 6-well plates. Hanging inserts with biofilm were treated in a custom exposure chamber designed to minimize unwanted ultrasound reflections. Coincident delivery of both energies demonstrated synergy over either alone, killing both stationary planktonic and biofilm cultures of P. acnes. Biofilm killing was dose dependent on exposure time (i.e. energy delivered). P. acnes biofilms were significantly reduced by the dual energy treatment (p<0.0001), with a >1 log10 reduction after a 5 min (9 J/cm^2) and >3 log10 reduction after a 30 min (54 J/cm^2) treatment (p<0.05). Mammalian cells were found unaffected by the treatment. Both the light and the ultrasound energies are at levels previously cleared by the FDA. Therefore, this combination treatment could be used as a safe, efficacious method to treat biofilm related syndromes.
ARTICLE | doi:10.20944/preprints202101.0410.v1
Subject: Medicine And Pharmacology, Immunology And Allergy Keywords: Elettaria cardamomum; GC-MS, compositions; antibacterial; antidiarrhoeal; antispasmodic
Online: 21 January 2021 (09:13:58 CET)
The present study examined the volatile composition and antimicrobial and gastrointestinal activity of the essential oils of Elettaria cardamomum (L.) Maton harvested in India (EC-I) and Guatemala (EC-G). Monoterpene were present in higher concentration in EC-I (83.24%) than in EC-G (73.03%), whereas sesquiterpenes were present in higher concentration in EC-G (18.35%) than in EC-I (9.27%). Minimum inhibitory concentrations (MICs) of 0.5 and 0.1 mg/mL were demonstrated against Pseudomonas aeruginosa in EC-I and EC-G, respectively, whereas MICs of 0.125 and 1 mg/mL were demonstrated against Escherichia coli in EC-I and EC-G, respectively. The treatment with control had the highest kill-time potential, whereas the treatment with oils had shorter kill-time. EC-I was found to be more potent in the castor oil-induced diarrhoea model than EC-G. At 100 and 200 mg/kg, EC-I exhibited 40% and 80% protection, respectively, and EC-G exhibited 20% and 60% protection, respectively, in mice, whereas loperamide (positive control) exhibited 100% protection. In the in vitro experiments, EC-I inhibited both carbachol (CCh, 1 µM) and high K+ (80 mM)-induced contractions at significantly lower concentrations than EC-G. Thus, EC-I significantly inhibited P. aeruginosa and E. coli and exhibited more potent antidiarrheal and antispasmodic effects than EC-G.
ARTICLE | doi:10.20944/preprints202005.0252.v1
Subject: Chemistry And Materials Science, Surfaces, Coatings And Films Keywords: Electrophoretic deposition; design of experiment; hydroxyapatite; chitosan; antibacterial
Online: 15 May 2020 (10:01:20 CEST)
In this study, silver-strontium doped hydroxyapatite (AgSr-HA)/chitosan composite coatings were deposited on stainless steel (SS) substrate via electrophoretic deposition (EPD) technique. The EPD parameters such as the concentration of Ag Sr-HA particles in the suspension, applied voltage and deposition time were optimized on by the Taguchi Design of Experiment (DoE) approach. DOE approach elucidated that the “best” coating was obtained at; the deposition voltage of 20V, deposition time of 7 minutes, and at 5 g/L of Ag Sr-HA particles in the suspension. The optimum coatings were characterized by using scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) spectroscopy. SEM images confirmed the deposition of chitosan/Ag Sr-HA on the SS substrate. The wettability studies indicated the hydrophilic nature of the chitosan/Ag Sr-HA coatings, which confirmed the suitability of the developed coatings for orthopedic applications. The average surface roughness of the chitosan/Ag Sr-HA coatings was in a suitable range for the attachment of bone marrow stromal cells. Chitosan/Ag Sr-HA coatings showed a potent antibacterial effect against the Gram-Positive and Gram-negative bacteria.
ARTICLE | doi:10.20944/preprints201905.0298.v1
Subject: Chemistry And Materials Science, Chemical Engineering Keywords: silver nanoparticles; nano-TiO2; nano- ZnO; nanohybrids; antibacterial
Online: 24 May 2019 (12:44:36 CEST)
This work emphasizes to use silver decorative method to enhance the antibacterial activity of TiO2 and ZnO nanoparticles. These silver decorated nanoparticles (hybrid nanoparticles) were synthesized by using sodium borohydride as a reducing agent, with the weight ratio of Ag precursors: oxide nanoparticles = 1: 30. The morphology and optical property of these hybrid nanoparticles were investigated using transmission electron microscopy (TEM) and UV–vis spectroscopy. The agar-well diffusion method was used to evaluate their antibacterial activity against both Staphylococcus aureus and Escherichia coli bacteria, with or without light irradiation. The TEM images indicated clearly that silver nanoparticles (AgNPs, 5-10 nm) were well deposited on the surface of nano-TiO2 particles (30-60 nm). Besides, smaller AgNPs (< 2 nm) were dispersed on the surface of nano-ZnO particles (20-50 nm). UV-vis spectra confirmed that the hybridization of Ag and oxide nanoparticles led to shift the absorption edge of oxide nanoparticles to the lower energy region (visible region). The antibacterial tests indicated that both oxide pure nanoparticles did not exhibit inhibitory against bacteria, with or without light irradiation. However, the presence of AgNPs in their hybrids, even at low content (< 40 mg/mL) leads to a good antibacterial activity and the higher inhibition zones under light irradiation as compared to that in dark was observed.
ARTICLE | doi:10.20944/preprints201901.0216.v1
Subject: Medicine And Pharmacology, Pharmacology And Toxicology Keywords: Phloroglucide, Polyhydroxyl aromatic compounds, SiO2-BTSA, Antifungal, Antibacterial.
Online: 22 January 2019 (11:30:45 CET)
An efficient procedure for the synthesis of polyhydroxyl aromatic compounds (phloroglucide analogs) is described. In this procedure a reaction was done between different 4-substituted phenols and 2,6-bis(hydroxymethy) phenols. The reactions proceed in the presence of catalytic amount of silica gel supported boric tri-sulfuric anhydride (SiO2-BTSA) in excellent yields. 16 compounds were synthesized (I1-I16). Chemical structures of all compounds were confirmed by spectroscopic methods. We optimized the chemical reactions in the presence of different acidic catalysts, different solvents and also different temperatures. Catalytic amounts of SiO2-BTSA in dichloroethane (DCE) was the best conditions. Some of the synthesized compounds were screened for their antimicrobial activities. Antifungal and antibacterial activities of the synthesized compounds were evaluated by broth micro dilution method as recommended by CLSI. Some of the tested compounds show good in vitro biological properties.
ARTICLE | doi:10.20944/preprints201807.0472.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: chitosan; quorum sensing; antibacterial activity; quorum sensing inhibition
Online: 25 July 2018 (08:32:31 CEST)
New approaches to deal with drug-resistant pathogenic bacteria are urgent. We studied the antibacterial effect of chitosans against an E. coli quorum sensing biosensor reporter strain, and selected a non-toxic chitosan to evaluate its QS inhibition activity and its effect on bacterial aggregation. To this end, chitosans of varying DA (12 to 69%) and Mw (29 to 288 KDa) were studied. Only chitosans of low DA (~12%) inhibited the bacterial growth, regardless of the Mw. Chitosan MDP DA30 (DA 42% and Mw 115 kDa) was selected for further QS inhibition and SEM imaging studies. MDP DA30 chitosan exhibited QS inhibition activity in an inverse dose-dependent manner (≤12.5 µg/mL). SEM images revealed that this chitosan, when added at low concentration (≤30.6 µg/mL), induced substantial bacterial aggregation, whereas at high concentration (234.3 µg/mL), it did not. Aggregation explains the QS inhibition activity as the consequence of retardation of the diffusion of AHL.
ARTICLE | doi:10.20944/preprints201705.0131.v1
Subject: Chemistry And Materials Science, Nanotechnology Keywords: green synthesis; silver nanoparticles; particle size; antibacterial efficacy
Online: 17 May 2017 (11:22:09 CEST)
Silver nanoparticles (AgNPs) have been demonstrated to restrain bacterial growth while maintaining the minimal risk in development of bacterial resistance and human cell toxicity that conventional silver compounds exhibit. Several physical and chemical methods have been reported to synthesize AgNPs. However, these methods are expensive and involve heavy chemical reduction agents. An alternative approach to produce AgNPs in a cost-effective and environmentally friendly way employs a biological pathway using various plant extracts to reduce metal ions. The size control issue and the stability of nanoparticles remain some of the latest challenges in such methods. In this study, we used two different concentrations of fresh leaf extract of the plant Arbutus Unedo (LEA) as a reducing and stabilizing agent to produce two size variations of AgNPs. UV-Vis spectroscopy, Dynamic Light Scattering, Transmission Electron Microscopy and zeta potential were applied for the characterization of AgNPs. Both AgNP variations were evaluated for their antibacterial efficacy against the gram-negative species Escherichia coli and Pseudomonas aeruginosa, as well as the gram-positive species Bacillus subtilis and Staphylococcus epidermidis. Although significant differences have been achieved in the nanoparticles’ size by varying the plant extract concentration during synthesis, the antibacterial effect was almost similar.
REVIEW | doi:10.20944/preprints201703.0072.v1
Subject: Chemistry And Materials Science, Biomaterials Keywords: micro-arc oxidation; antibacterial ability; Ag; Cu; Zn
Online: 14 March 2017 (07:49:40 CET)
Ti and its alloys are the most commonly used materials for biomedical applications. However, bacterial infection after implant placement is still one of the significant rising complications. Therefore, the application of the antimicrobial agents into implant surfaces to prevent implant-associated infection has attracted lots of attention. Scientific papers have shown that inorganic antibacterial metal element (e.g. Ag, Cu, Zn) can be introduced to implant surfaces with the addition of metal nanoparticles or metallic compounds into electrolyte via micro-arc oxidation (MAO) technology. In this review, the effects of the composition and concentration of electrolyte and process parameters (e.g. voltage, current density, oxidation time) on morphological characteristics (e.g. surface morphology, bonding strength), antibacterial ability and biocompatibility of MAO antimicrobial coating were discussed in detail. Anti-infection and osseo-integration can be simultaneously accomplished with the selection of the proper antibacterial elements and operating parameters. Besides, MAO assisted by magnetron sputtering (MS) to endow Ti-based implant materials with superior antibacterial ability and biocompatibility was also discussed. Finally, the development trend of MAO technology in the future was forecasted.
ARTICLE | doi:10.20944/preprints201612.0121.v1
Subject: Medicine And Pharmacology, Dermatology Keywords: antibacterial activity, cinnamon, honey, checkerboards method, synergistic activity
Online: 23 December 2016 (18:37:59 CET)
Propionibacterium acnes and Staphylococcus epidermidis are the major skin bacteria that cause the formation of acne. The present study was conducted to investigate antibacterial activity of ethanolic extract of cinnamon bark, honey and their combination against acne bacteria. The antibacterial activity of extract of cinnamon bark and honey were investigated against P. acnes and S. epidermidis using disc diffusion method. Minimum Inhibitory Concentration (MIC) and minimal bactericidal concentration (MBC) were performed using Clinical and Laboratory Standard Institute (CLSI) methods. The interaction combination between extract of cinnamon bark and honey was determined by using a checkerboards method. The results showed that he MIC of extract of cinnamon bark and honey against P. acne were 256 µg/mL and 50% v/v, respectively, while against S. epidermidis were 1024 µg/mL and 50% v/v, respectively. The MBC of extract of cinnamon against P. acnes and S. epidermidis were more than 2048 µg/mL, whereas the MBC for honey against P. acnes and S. epidermidis were 100%. The combination of cinnamon bark extract and honey against against P. acnes and S. epidermidis, showed additive activity with the FICI value 0.625. Therefore, the combination of extract of cinnamon bark and honey has potential activity against acne causing bacteria.
ARTICLE | doi:10.20944/preprints202311.0926.v1
Subject: Chemistry And Materials Science, Polymers And Plastics Keywords: Nanofiber; Biocomposites; Poly(lactic acid); Silver nanoparticles; Antibacterial properties.
Online: 15 November 2023 (04:01:42 CET)
Nanofibers are one of the most attractive materials that can modify functionalities for developing new kinds of specific applications, mainly used as a biomedical material. Herein, we designed and prepared the antibacterial nonwoven fiber mats of PLA and PLA composited with Ag nanoparticles by electrospinning. The effects of varying filler contents on their chemical, surface morphology, thermal, water absorbency, and antibacterial properties were investigated using FTIR, SEM/EDS, DSC, swelling ratio, and qualitative and quantitative antibacterial tests. FTIR and EDS spectra indicated that Ag nanoparticles were incorporated in the PLA without chemical bonding. SEM revealed that the average diameter of the PLA nanofibers containing the Ag nanoparticles was more significant than those without those particles. Besides, fiber diameters are proportionally the amount of Ag nanoparticle contents. DSC indicated that the Ag nanoparticles can be incorporated within the PLA-matrix without strongly affecting their thermal properties. Moreover, the crystallinity of the composite nonwoven fiber mats was higher than those of fiber mats in the neat PLA. Accordingly, the antibacterial activities revealed that all the composite nanofiber mats exhibited excellent against S. aureus and E. coli bacterial strains. In addition, in the cell toxicity study, all produced hybrids nonwoven fiber mats induced a reduction in cell viability for the L929 fibroblast cells. Our results suggest that the designed and prepared nonwoven fiber mats may have good potential for use in the biomedical field, particularly in wound dressing applications
ARTICLE | doi:10.20944/preprints202310.0084.v1
Subject: Chemistry And Materials Science, Biomaterials Keywords: bioactive glass; zinc oxide; nanoparticle; enamel remineralization; antibacterial property
Online: 3 October 2023 (03:09:36 CEST)
Background: We investigated the effect of bioactive glass and zinc oxide nanoparticles on enamel remineralization, as well as their antibacterial effect on cariogenic bacteria. Methods: Fluoride gel (F), bioactive glass microparticles (µB), bioactive glass nanoparticles (nB), zinc oxide nanoparticles (Z), and a mixed suspension of nB and Z (nBZ) were prepared and subjected to the following tests: morphological evaluation by scanning and transmission electron microscopy, measurement of specific surface area, zeta potential measurement, crystal structure analysis by X-ray diffraction, and acid buffering capacity test. Further, we performed a remineralization cycle test of 28 days and a nanoindentation testing was carried out during the immersion period and then the enamel surfaces were examined using scanning electron microscopy. Additionally, the antibacterial effects of the sample suspensions were evaluated by measuring their minimum bactericidal concentrations against various cariogenic bacteria. Results: Our results revealed that nB had a near-circular shape with an amorphous structure, a considerably large specific surface area due to nanoparticulation. Additionally, nB possessed a rapid acid buffering capacity, which was comparable to that of μB. In the remineralization test, faster recovery of mechanical properties was observed on the enamel surface immersed in samples containing bioactive glass nanoparticles (nB and nBZ). After remineralization, demineralized enamel immersed in any of the samples showed a rough and porous surface structure covered with mineralized structures. Furthermore, nBZ exhibited a broad antibacterial spectrum. Conclusions: These results demonstrated that bioactive glass and zinc oxide nanoparticles have superior demineralization-suppressing and remineralization-promoting effects.
ARTICLE | doi:10.20944/preprints202309.1506.v1
Subject: Chemistry And Materials Science, Organic Chemistry Keywords: antibacterial; anticancer activity, dihydropyridin-4(1H)-ones; tetrahydropyridinylidene salts
Online: 22 September 2023 (08:24:17 CEST)
Various 4-aminotetrahydropyridinylidene salts were treated with aldehydes in alkaline medium. Their conversion to 5-substituted -hydroxyketones in a one-step reaction succeeded only with an aliphatic aldehyde. Instead, aromatic aldehydes gave 5-substituted -aminoketones or a single -diketone. The new compounds were characterized by spectroscopic methods and a single crystal structure analysis. Some of them showed anticancer and antibacterial properties.
ARTICLE | doi:10.20944/preprints202307.1883.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: antibacterial; antioxidant; anti-inflammatory activity; E. radiata; E. cinerea
Online: 27 July 2023 (08:19:02 CEST)
Eucalyptus, a therapeutic plant mentioned in the ancient Algerian pharmacopeia, specifically two species belonging to the Myrtaceae family - E. radiata and E. cinerea, were investigated in this study for their antibacterial, antioxidant, and anti-inflammatory properties. The study used aqueous extracts (AE) obtained from these plants, and the extraction yields were found to be dif-ferent. The in vitro antibacterial activity was evaluated using a disc diffusion assay against three typical bacterial strains. The results showed that E. radiata EAq was effective against all three strains, while E. cinerea EAq was only effective against E. coli. Both extracts displayed significant antioxidant activity compared to BHT. The anti-inflammatory impact was evaluated using a pro-tein (BSA) inhibition denaturation test. The E. radiata extract was found to inhibit inflammation by 75% at a concentration of 250 g/ml, significantly higher than the placebo. Ellagic acid, a pri-mary phytochemical found in the extracts, demonstrated noteworthy toxic and pharmacokinetic characteristics and a maximum binding energy of -7.53 kcal/mol for its anti-TyrRS activity in sili-co. The study suggests that the extracts and their primary phytochemicals could enhance the effi-cacy of antibiotics, antioxidants, and non-steroidal anti-inflammatory drugs (NSAIDs). As phar-maceutical engineering experts, we believe this research contributes to developing natural-based drugs with potential therapeutic benefits.
ARTICLE | doi:10.20944/preprints202307.0198.v1
Subject: Medicine And Pharmacology, Medicine And Pharmacology Keywords: covalent antibacterial conjugate; moxifloxacin; limonene; prolonged pharmacokinetic; FTIR spectroscopy
Online: 4 July 2023 (11:42:37 CEST)
Potentially, such an approach would significantly increase the effectiveness of therapy for a number of infectious and other diseases, reduce the dosage of antibiotics, shorten the duration of treatment, and reduce the risk of developing resistance. Moreover, the use of a polymer carrier with covalently bound organic molecules of different structures avoids problems with different (suboptimal) solubility and bio-distribution, which would be almost inevitable when using the same compounds separately. It would be very difficult to find antibiotic/adjuvant pairs that simultaneously achieve optimal concentrations in the same target cells. In our case, terpenoids and alkylbenzenes used as adjuvants are practically insoluble as individual compounds and their unacceptable pharmacological properties would not allow them to be used as efflux pump inhibitors.
ARTICLE | doi:10.20944/preprints202306.0503.v2
Subject: Chemistry And Materials Science, Nanotechnology Keywords: Curcumin; MOF; Sodium Alginate Hydrogel; Drug Release; Antibacterial Activity
Online: 12 June 2023 (05:29:21 CEST)
Management of chronic inflammation and wounds has always been a key issue in the pharmaceutical and healthcare sector. Curcumin (CCM) is an active ingredient extracted from turmeric rhizomes that has antioxidant, anti-inflammatory, and antibacterial activities, thus showing significant effectiveness toward wound healing. However, its shortcomings such as poor water solubility, poor chemical stability and fast metabolic rate limit its bioavailability and long-term use. In this context, hydrogels appear to be a versatile matrix for carrying and stabilizing drugs due to the biomimetic structure, soft porous microarchitecture, and pleasant biomechanical properties. The drug loading/releasing efficiencies can also be controlled by use of highly crystalline and porous metal organic frameworks (MOFs). Here, a flexible hydrogel composed of sodium alginate (SA) matrix and CCM-loaded MOFs was constructed for long-term drug release and antibacterial activity. The morphology and physicochemical properties of composite hydrogels were analyzed by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), ultraviolet visible spectroscopy (UV-Vis), Raman spectroscopy and mechanical property tests. The results showed that the composite hydrogel was highly twistable and bendable to mechanically comply with human skin. The as-prepared hydrogel could capture efficient CCM for slow drug release as well as effective killing of bacteria. Therefore, such composite hydrogel is expected to provide a new management system for chronic wound dressings.
ARTICLE | doi:10.20944/preprints202306.0564.v1
Subject: Chemistry And Materials Science, Medicinal Chemistry Keywords: Green Synthesis; Pectin functionalized silver nanoparticles; Antibacterial activity; Hepatoprotective
Online: 7 June 2023 (14:22:20 CEST)
Present study reports the green synthesis of pectin fabricated silver-based nanocomposite (Pectin-AgNPs) with Carpesiumnepalense leaves extract and evaluated their bactericidal kinetics, in-vivo hepatoprotective and cytotoxic potentials with their possible mechanisms. GC/MS and LC/MS analysis indicated the presence of different new phytochemicals constituents in the plant extract. The physicochemical characterization of Pectin-AgNPs by UV/Vis, SEM, DLS, FTIR and EDX techniques showed the spherical and uniform size range synthesis of nanocomposite i.e. 50-110 nm. The highly significant (P<0.005) antibacterial activity was found against all tested four bacterial strains with the ZIs of 24.8 to 27.2 mm. Significant damage in bacterial cell membrane was also observed in AFM study after treated with Pectin-AgNPs. At the doses of 0.05 mg/kg, nanocomposite showed highly significant (P<0.005)hepatoprotective activity in biochemical and histopathology analysis as compared to CCL4 administered control group. The ameliorative effects of Pectin-AgNPs were observed in PCR analysis on both GAPDH and PPARs genes expression and its potential to restore gene alterations caused by CCl4 intoxication.Pectin-AgNPs produced cytotoxic activity against HeLa cell lines at higher doses with the LC50 of 223.7 µg/mL. The current findings demonstrate positive attributes of pectin fabricated AgNPs as a promising antibacterial, hepatoprotective and cytotoxic agent.
ARTICLE | doi:10.20944/preprints202306.0502.v1
Subject: Chemistry And Materials Science, Biomaterials Keywords: resveratrol; curcumin; halloysite nanotubes; kojic acid; iron chelation, antibacterial.
Online: 7 June 2023 (07:15:16 CEST)
Nowadays, there is evidence that bacteria can contribute to cancer formation and interfere with therapy by mediating its carcinogenesis and related infection. Moreover, it is acknowledged that microbial infections and antibiotic resistance represent severe economic and health risks to society. These facts have led to the developing of several new techniques for impeding crucial biological processes in microbial cells. One of these techniques centers on using metal-chelating agents, which can disrupt the microorganism's vital metal metabolism by obstructing metal uptake and bioavailability for critical reactions. Additionally, nanotechnology has made a wide range of nanomaterials available for possible uses in the antibacterial industry. This complex field is shaped by antimicrobial nanoparticles, also investigated as therapeutic and drug-delivery tools. Halloysite nanotubes (HNTs) are naturally occurring tubular clay nanomaterials consisting of aluminosilicate kaolin sheets rolled up several times. The aluminon and siloxane groups on the surface of HNTs facilitate the formation of hydrogen bonds with biomaterials on their surface. These properties make HNTs crucial in a wide range of applications, such as in environmental sciences, wastewater treatment, dye removal, nanoelectronics and nanocomposite fabrication, catalytic studies, coatings for glass or anti-corrosive coatings, cosmetics, flame retardants, stimulus-response, and in forensic sciences. This work aimed to produce an antibacterial material by combining the properties of halloysite nanotubes with the ability of kojic acid to chelate iron. Starting from kojic acid, a simple nucleophilic substitution involving the hydroxyl groups on the surface of the nanotubes was performed. The obtained material was characterized by IR and SEM, and its ability to chelate iron was evaluated. Finally, the capacity to load drugs such as resveratrol and curcumin was also evaluated by UV analysis. In this way, a new bio-based material that can be used as a drug carrier and antimicrobial was produced.
ARTICLE | doi:10.20944/preprints202305.2101.v1
Subject: Chemistry And Materials Science, Biomaterials Keywords: calcium phosphate; magnesium phosphate; bone cement; antibacterial properties; ; cytocompatibility
Online: 30 May 2023 (09:45:06 CEST)
The development of magnesium calcium phosphate bone cements (MCPCs) have garnered big attention. MCPCs are bioactive and biodegradable and have appropriate mechanical and antimicrobial properties for use in reconstructive surgery. In this study, the cement powders based on a (Ca + Mg)/P = 2 system doped with Zn2+ at 0.5 and 1.0 wt.% were obtained and investigated. After the mixing with a cement liquid, structural and phase composition, morphology, chemical structure, setting time, compressive strength, degradation behavior, solubility, antibacterial activities, and in vitro behaviour of the cement materials were examined. A high compressive strength of 48 ± 5 MPa (mean ± SD) was achieved for the cement made from Zn2+ 1.0-wt.%-substituted powders. The Zn2+ introduction led to antibacterial activity against Staphylococcus aureus and Escherichia coli strains, with an inhibition zone diameter up to 8 mm. Biological assays confirmed that the developed cements are cytocompatible and promising as a potential bone substitute in reconstructive surgery.
ARTICLE | doi:10.20944/preprints202305.1085.v1
Subject: Chemistry And Materials Science, Physical Chemistry Keywords: N-doped graphene carbon nanoparticles; antibacterial ability; Escherichia coli
Online: 16 May 2023 (04:53:48 CEST)
Graphene-based nanomaterials have emerged as promising materials for a wide range of applications.. Therefore, in the last years carbon nanoparticles have attracted great attention due to their low toxicity, high biocompatibility and easy preparation. Recently, N-doped carbon nanoparticles have been shown to have improved antibacterial activity over the undoped nanomaterial, but it is difficult to find correlations between the structure of the nanoparticle and its antibacterial activity. With this purpose, here, we analyze the effect of both, the nanoparticle size and the surface chemical composition of four N-doped carbon nanoparticles on the growth of Escherichia coli bacteria. Our results were analyzed using a Ligand-Substrate model based on the Monod´s equation, which allows us to interpret the dependence of the nanoparticle-bacteria affinity with the nanomaterial structure.
ARTICLE | doi:10.20944/preprints202303.0098.v2
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Antibacterial activity; Psidium guajava; phytochemical screening; liquid-liquid fractionation
Online: 14 March 2023 (04:07:51 CET)
Guava (Psidium guajava L.) is a common fruit tree that grows in several tropical and subtropical parts of the world. The aim of this study was to employ the use of liquid-liquid fractionation to investigative the comparative antibacterial potential of crude extracts of Guava leaves and bark against selected food isolates; Escherichia coli, Pseudomonas aeruginosa, Streptococcus pneumonia, Bacillus cereus and Staphylococcus aureus. The phytochemical analysis of the extract showed presence of tannin, phenol, flavonoid and terpenoid in all extract, while steroid and saponin were absent in some. The agar diffusion method was employed for the assessment of the sensitivity of the extracts. The ethyl acetate and aqueous fractions from the stem bark acetone extract generally showed better antimicrobial activity compared with other extracts from leaves. The extract was active both against gram positive bacteria (Bacillus cereus and Streptococcus pneumonia) and gram negative bacteria (Escherichia coli, Pseudomonas aeruginosa, , Bacillus cereus and Staphylococcus aureus) at varying zone of inhibition. The results of the study showed the potential of identifying novel antibacterial agent from P. guajava bark and leaves while optimising the potential application for treatment in traditional medicine.
REVIEW | doi:10.20944/preprints202211.0494.v1
Subject: Chemistry And Materials Science, Nanotechnology Keywords: SnO2 NPs and their nanocomposites; Photocatalysis; Supercapacitors; Antibacterial activities
Online: 28 November 2022 (04:43:28 CET)
Tin (IV) oxide nanoparticles (SnO2 NPs) have received a lot of interest because of their interesting features. SnO2 NPs have proven productive in a range of fields, including water purification, supercapacitors, batteries, antibacterial and antioxidant agents, and others. SnO2-based nanoparticles found a wide range of applications after incorporating materials with varying chemical compositions. SnO2 NPs and their nanocomposites have been used effectively as antibacterial agents against various pathogenic bacteria, photocatalysts for dye degradation, and electrode materials for supercapacitors (SCs). This article covers the characteristics of SnO2 NPs, SnO2 nanocomposite materials, applications of SnO2 NPs and their composite materials, including antibacterial, energy storage, and photocatalysis, as well as some significant recent studies.
ARTICLE | doi:10.20944/preprints202209.0143.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Salmonella; novel antibacterial agents; cannabidiol; co-therapy; bacterial genetics
Online: 12 September 2022 (09:55:22 CEST)
New generation antibiotics are needed to combat the development of resistance to antimicrobials. One of the most promising new classes of antibiotics is cannabidiol (CBD). It is a non-toxic and low-resistance chemical that can be used to treat bacterial infections. The antibacterial activity of Cannabis sativa L. byproducts, specifically CBD, has been of growing interest in the field of novel therapeutics. As research continues to define and characterize the antibacterial activity that CBD possesses against a wide variety of bacterial species it is important to examine potential interaction between CBD and common therapeutics such as broad-spectrum antibiotics. Here, we show that CBD-antibiotic co-therapy can effectively fight S. typhimurium via membrane integrity disruption. This research serves to examine the potential synergy between CBD and three broad-spectrum antibiotics for potential antibiotic-CBD co-therapy. In this study, we reveal that Salmonella typhimurium (S. typhimurium) growth is inhibited at very low dosages of CBD-antibiotic. This interesting finding demonstrates that CBD and CBD-antibiotic co-therapies are viable novel alternatives to combating Salmonella typhimurium.
ARTICLE | doi:10.20944/preprints202206.0352.v1
Subject: Chemistry And Materials Science, Surfaces, Coatings And Films Keywords: Electrophoretic deposition; mesoporous bioactive glass nanoparticles; adhesion; antibacterial; bioactive
Online: 27 June 2022 (08:01:22 CEST)
In recent years, natural polymers have replaced synthetic polymers for antibacterial orthopedic applications owing to their excellent biocompatibility and biodegradability. Zein is a biopolymer found in corn. The lacking mechanical stability of zein is overcome by incorporating bioceramics e.g. mesoporous bioactive glass nanoparticles (MBGNs). In present study, pure zein and zein/Zn-Mn MBGNs composite coatings were deposited via electrophoretic deposition (EPD) on 316L stainless steel (SS). Zn and Mn were co-doped in MBGNs in order to make use of their antibacterial and osteogenic potential, respectively. A Taguchi design of experiment (DoE) study was established to evaluate the effect of various working parameters on the morphology of the coatings. It was observed that coatings deposited at 20 V for 5 min with 4 g/L concentration (conc.) of Zn-Mn MBGNs showed highest deposition yield. Uniform coatings with highly dispersed MBGNs were obtained adopting these optimized parameters. Scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-Ray diffraction (XRD), and fourier transform infrared spectroscopy (FTIR) were employed to investigate the morphology and elemental composition of zein/Zn-Mn MBGNs composite coating. Surface properties i.e. coating roughness and wettability analysis concluded that composite coatings were appropriate for cell attachment and proliferation. For adhesion strength various techniques including tape test, bend test, pencil hardness test, and tensile test were performed. Wear and corrosion analysis highlighted the mechanical and chemical stability of coatings. Colony forming unit (CFU) test showed that zein/Zn-Mn MBGNs composite coating was highly effective against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) due to the presence of Zn. The formation of hydroxyapatite (HA) like structure upon immersion in simulated body fluid (SBF) validated the in vitro bioactivity of the coating. It was concluded that zein/Zn-Mn MBGNs coating synthesized in this work can be used for bioactive and antibacterial orthopedic applications.
ARTICLE | doi:10.20944/preprints202105.0371.v1
Subject: Chemistry And Materials Science, Biomaterials Keywords: carboxymethy chitosan; corn peptide; antioxidant activity; antibacterial activity; film
Online: 17 May 2021 (07:59:06 CEST)
Active films based on carboxymethyl chitosan incorporated corn peptide were developed. Physicochemical properties of the films, including thickness, opacity, moisture content, color, mechanical properties, water vapor permeability, and oil resistance, were measured. Biological activities of the films, including the antioxidant and antibacterial activities, were characterized in terms of 2, 2-diphenyl-1-picrylhydrazyl free radical scavenging activity, reducing power, the total antioxidant activity, and the filter disc inhibition zone method. The results indicated that the incorporation of corn peptide caused interactions between carboxymethyl chitosan and corn peptide in Maillard reaction and gave rise to the films light yellow appearance. Compared with the Control, the degree of glycosylation, browning intensity, thickness, opacity, tensile strength, antioxidant activity, and antibacterial activity of films were increased, but the elongation, vapor permeability, and oil resistance of films were decreased. The films based on corn peptide and carboxymethyl chitosan can potentially be applied to food packaging.
REVIEW | doi:10.20944/preprints202105.0337.v1
Subject: Medicine And Pharmacology, Immunology And Allergy Keywords: antibacterial agents; antibiotics; COVID-19; drug misuse; odontogenic infection
Online: 14 May 2021 (14:03:42 CEST)
This review revisits clinical use of antibiotics for most common acute oro-dental conditions; we aim to provide evidence governing antibiotics use when access to oral healthcare is not available, as during the ongoing outbreak of the severe acute respiratory syndrome coronavirus 2. In this rapid review, articles were retrieved after conducting a search on PubMed and Google Scholar. Relevant publications were selected and analyzed. Most recent systematic reviews with/without meta-analyses and societal guidelines were selected. Data were extracted, grouped, and synthesized according to the respective subtopic analysis. There were evidence supporting the use of antibiotics in common oro-dental conditions as temporary measure when immediate care is not accessible, such as in case of localized oral swellings as well as to prevent post-extraction complications. No sufficient evidence could be found in support of antibiotic use for pain resulting from pulpal origin. Consequently, antibiotic use may be justified to defer treatment temporarily or reduce risk of complications in case of localized infection and tooth extraction, when no access to immediate dental care is possible.
ARTICLE | doi:10.20944/preprints202102.0282.v1
Subject: Chemistry And Materials Science, Analytical Chemistry Keywords: Fuscoporia torulosa; triterpenes; cytotoxic; antioxidant; synergism; antibacterial; ORAC; DPPH
Online: 11 February 2021 (11:45:31 CET)
Investigation of the methanol extract of the poroid fungus Fuscoporia torulosa resulted in the isolation of a novel triterpene, fuscoporic acid (1) together with inoscavin A and its previously undescribed Z isomer (2 and 3), 3,4-dihydroxy-benzaldehide (4), osmundacetone (5), senexdiolic acid (6), natalic acid (7), and ergosta-7,22-diene-3-one (8). The structures of fungal compounds were determined on the basis of NMR and MS spectroscopic analysis, as well as molecular modelling studies. Compounds 1, 6-8 were examined for their antibacterial properties on resistant clinical isolates, and cytotoxic activity on human colon adenocarcinoma cell lines. Compound 8 was effective against Colo 205 (IC50 11.65±1.67 µM), Colo 320 (IC50 8.43±1.1 µM) and MRC-5 (IC50 7.92±1.42 µM) cell lines. Potentially synergistic relationship was investigated between 8 and doxorubicin, which revealed a synergism between the examined compounds with a combination index (CI) at the 50% growth inhibition dose (ED50) of 0.521±0.15. Several compounds (1, and 6-8) were tested for P‐glycoprotein modulatory effect in Colo 320 resistant cancer cells, but none of the compounds proved to be effective in this assay. Fungal metabolites 2-5 were evaluated for their antioxidant activity using the oxygen radical absorbance capacity (ORAC) and DPPH assays. Compounds 4 and 5 proved to possess considerable antioxidant effect with EC50 0.25±0.01 (DPPH) and 12.20±0.92 mmol TE/g (ORAC). The current article provides valuable information on both chemical and pharmacological profiles of Fuscoporia torulosa, paving the way for future studies with this species.
ARTICLE | doi:10.20944/preprints202101.0481.v1
Subject: Chemistry And Materials Science, Biomaterials Keywords: Antibacterial activity; Endodontic irrigant; Enterococcus faecalis; Quercetin; Root canal
Online: 25 January 2021 (10:54:58 CET)
(1) Background: Bacterial reinfection and root fracture are the main culprits related to root canal treatment failure. This study aimed to assess the utility of quercetin solution as an adjunctive endodontic irrigant that strengthen root canal dentin with commitment anti-biofilm activity and bio-safety. (2) Methods: Based on a noninvasive dentin infection model, dentin tubules infected with Enterococcus faecalis (E. faecalis) were irrigated with sterile water (control group), and 0, 1, 2, 4 wt% quercetin-containing ethanol solutions. The live and dead bacteria proportions within E. fae-calis biofilms were analyzed using confocal laser scanning microscopy (CLSM). Elastic modulus and hydroxyproline release and X-ray photoelectron spectroscopy (XPS) characterization was tested on irrigant-treated demineralized dentin to evaluate irrigants’ biostability. The cytotoxicity of irrigants was tested by CCK-8 assay. (3) Results: Quercetin increased the proportion of dead bacteria volumes within E. faecalis, and improved the flexural strength of dentin collagen com-pared to control group. The XPS characterization revealed an increase in C-O peak area under both C1s and O1s narrow-scan spectra. The CCK-8 assay confirmed no cytotoxicity of quercetin solutions. (4) Conclusions: Quercetin exhibited anti-biofilm activity, collagen-stabilizing effect as well as cytocompatibility, supporting quercetin as a potential candidate for endodontic irrigant.
ARTICLE | doi:10.20944/preprints202010.0404.v1
Subject: Chemistry And Materials Science, Biomaterials Keywords: Bioactive glass; antibacterial; silver; nanocomposites; E. coli; ion release
Online: 20 October 2020 (08:34:22 CEST)
There is an increasing clinical need to develop novel biomaterials that combine regenerative and biocidal properties. In this work, we present the preparation of silver /silica based glassy bioactive (ABG) compositions via a facile, fast (20h), and low temperature (80 °C) approach and their characterization. The fabrication process included the synthesis of the bioactive glass (BG) particles followed by the surface modification of the bioactive glass with silver nanoparticles. The microstructural features of ABG samples before and after exposure to simulated body fluid (SBF) as well as their ion release behavior during SBF test were evaluated using infrared spectrometry (FTIR), ultraviolet- visible (UV-Vis) spectroscopy, X-ray diffraction (XRD), electron microscopies (TEM and SEM) and optical emission spectroscopy (OES). The antibacterial properties of the experimental compositions were tested against Escherichia coli (E. coli). The results indicated that the prepared ABG materials possess antibacterial activity against E. coli, which is directly correlated with the glass surface modification.
ARTICLE | doi:10.20944/preprints202007.0092.v1
Subject: Biology And Life Sciences, Animal Science, Veterinary Science And Zoology Keywords: Bacterial resistance; Animal venom; Purification; Antibacterial and antibiofilm activity
Online: 6 July 2020 (04:00:43 CEST)
Introduction: Bacterial resistance is a worldwide public health problem, requiring new therapeutic options. An alternative approach to this problem is the use of animal toxins, such as phospholipases (PLA2) isolated from snake venom, which have important biological activities. Bothrops erythromelas is one of the snake species in the Northeast of Brazil that attracts great medical-scientific interest. Here we aimed to purify and characterize a PLA2 from B. erythromelas, searching for heterologous activities against bacterial biofilm. Methods: Venom extraction and quantification were followed by RP-HPLC in C18 column, MALDI-ToF mass spectrometry and sequencing by Edman degradation. All experiments were monitored by specific activity using 4-nitro-3 (octanoyloxy) benzoic acid (4N3OBA) substrate. In addition, hemolytic tests and anti-bacterial tests including action against Escherichia coli, Staphylococcus aureus and Acinetobacter baumannii, were carried out. Moreover, tests of antibiofilm action against A. baumannii were also performed. Results: PLA2, after one purification step, presented 31 N-terminal amino acid residues, and molecular weight of 13656.4 Da with enzymatic activity confirmed in 0.06 µM concentration. Antibacterial activity against S. aureus (IC50 = 30.2 µM) and antibiofilm activity against A. baumannii (IC50 = 1.1 µM) were observed. Conclusions: This is the first time that PLA2 purified from B. erythromelas venom has appeared as an alternative candidate in studies of new antibacterial medicines.
ARTICLE | doi:10.20944/preprints201910.0370.v1
Subject: Chemistry And Materials Science, Materials Science And Technology Keywords: polyurethane; polylactide; tissue engineering; skin scaffold; antibacterial; degradable; medical
Online: 31 October 2019 (09:52:06 CET)
The aim of performed studies was to fabricate an antibacterial and degradable scaffold that may be used in the field of skin regeneration. To reach the degradation criterion the biocompatible polyurethane (PUR), obtained by using amorphous macrodiol α,ω-dihydroxy(ethylene-butylene adipate) macrodiol (PEBA), was used and processed with so-called “fast-degradable” polymer polylactide (PLA) (5 wt% or 10 wt%). To meet the antibacterial requirement obtained hybrid PUR-PLA scaffolds (HPPS) were modified with ciprofloxacin (Cipro) (2 wt% or 5 wt%), the fluoroquinolone antibiotic inhibiting growth of bacteria such as Pseudomonas aeruginosa, Escherichia Coli and Staphylococcus aureus, which are main cause of wound infections. Obtained unmodified and Cipro-modified HPPS were studied towards their chemical composition to detect presence or absence of characteristic functional groups of PUR, PLA and Cipro, and as well to indicate the participation of hydrogen bonds in the HPPS structure in dependence on PLA addition and ciprofloxacin modification. Mechanical properties were studied to determine the possible application of HPPS as a skin tissue scaffold. Scanning electron microscopy (SEM) was used to study morphology of unmodified and Cipro-modified HPPS and to performed elementary analysis by using energy-dispersive x-ray spectroscopy (EDX) of obtained materials. Finally, the microbiological tests were performed to indicate the antibacterial effect of Cipro-modified HPPS on S.aureus growth. Performed studies showed that Cipro-modified HPPS, obtained by using 5 % of PLA, possess suitable mechanical characteristic, morphology, degradation rate and demanded antimicrobial properties to be further developed as a potential scaffolds for skin tissue engineering.
REVIEW | doi:10.20944/preprints201905.0063.v1
Subject: Biology And Life Sciences, Ecology, Evolution, Behavior And Systematics Keywords: biotechnologies; marine bacteria; secondary metabolites; nonribosomal biosynthesis; antibacterial strategies
Online: 6 May 2019 (12:15:50 CEST)
The highly dangerous trend of escalating bacterial resistance to modern antibiotics has evolved in recent decades, with increasingly more drug-resistant strains of pathogens emerging and spreading each year. This poses a threat to not only public health, but also to entire mankind. Marine bioresources, considered as a promising alternative to traditional antibiotics and a valuable source of biologically active compounds with high pharmacological potential, now attract increasing attention of researchers. Modern biotechnology combines the genetic engineering methods and the unusual biosynthetic pathways utilized by marine microorganisms to produce natural antibiotics. The goal of this review is to summarize the latest trends in searching for new natural antimicrobial agents based on secondary metabolites of marine bacteria. The targeted control of biosynthesis mechanisms using the metabolic engineering methods in order to create hybrid peptide synthetases or to obtain hybrid peptides by disrupting the target gene of nonribosomal synthesis becomes a noteworthy trend in modern biotechnology. This pathway is not only one of the most promising approaches to the development of new antibiotics, but also a potential target for controlling the exocrine activity of pathogenic bacteria and, consequently, their viability.
ARTICLE | doi:10.20944/preprints201707.0093.v1
Subject: Chemistry And Materials Science, Inorganic And Nuclear Chemistry Keywords: triiodide; antibacterial activity; antifungal activity; sodium; crown ether complex
Online: 31 July 2017 (15:25:01 CEST)
New antibacterial agents are needed to overcome the increasing number of infectious diseases caused by pathogenic microorganisms due to the emergence of multi-drug resistant strains. In this context, halogens, especially Iodine is known since ages for its antimicrobial activity. Therefore, especially triiodides encapsulated in organometallic complexes can be helpful as new agents against microorganisms. The aims of this work was to study the biological activity of [Na(12-Crown-4)2]I3 against gram positive Streptococcus pyogenes, Streptococcus faecalis, the spore forming bacteria Bacillus subtilis and gram negative bacteria Escherichia coli, Proteus mirabilis, Pseudomonas aeruginosa and Klebsiella pneumoniae, as well as the yeast Candida albicans. The antimicrobial and antifungal activities of the triiodide were determined by zone of inhibition plate studies. [Na(12-Crown-4)2]I3 exhibited potent antimicrobial activity on gram positive Streptochocci and the yeast C. albicans. Furthermore, the gram negative bacteria P. aeruginosa and K. pneumoniae were less effectively inhibited, while E. coli and P. mirabilis proved to be even resistant.
ARTICLE | doi:10.20944/preprints201608.0013.v1
Subject: Chemistry And Materials Science, Medicinal Chemistry Keywords: α-mangostin; antibacterial; antifungal; food packaging; semi-synthetic modification
Online: 2 August 2016 (09:02:09 CEST)
The microbial contamination in food packaging have been a major concern that paved the way for the search for natural based new anti-microbial agents, such as modified α-mangostin. In the present work, twelve synthetic analogs were obtained via semi-synthetic modification of α-mangostin by Ritter reaction, reduction by palladium-carbon (Pd-C), alkylation, and acetylation. The evaluation of the anti-microbial potential of the synthetic analogs showed higher therapeutic value than the parent molecule. The anti-microbial studies proved that I E showed higher antibacterial activity whereas I I showed most significant antifungal activity. Due to their microbial properties, modified α-mangostin can be utilized as active anti-microbial agents in food packaging.
ARTICLE | doi:10.20944/preprints202311.0868.v1
Subject: Chemistry And Materials Science, Biomaterials Keywords: silver nanoparticles; Fructus mori; green synthesis; antibacterial properties; antioxidant activity
Online: 14 November 2023 (10:45:24 CET)
Novel antibacterial silver nanomaterials have become promising substitutes for traditional antibiotics, because pathogens do not develop resistance to them. However, it is necessary to produce silver nanoparticles with appropriate size and better performance through a green and simple synthesis process. In the present study, Fructus mori-composite silver nanoparticles (M-AgNPs) were greenly synthesized using medicinal plant mulberry fruits (Fructus mori), with silver nitrate (AgNO3) as a precursor. UV-Vis spectroscopy and X-ray diffraction (XRD) indicated the formation of silver nanoparticles with face centered cubic structure. Fourier transform infrared (FTIR) spectroscopy confirmed the reducing and capping effects of mulberry fruits' active components (polyphenols, flavonoids, etc.) on M-AgNPs. The reaction parameters including temperature, time, pH, and concentration of AgNO3 were gradually optimized. The particle size and morphology of M-AgNPs were measured by dynamic light scattering (DLS) and transmission electron microscopy (TEM) techniques. The minimum particle size of M-AgNPs was about 30 nm, and they were approximately spherical and equably distributed. The excellent stability of M-AgNPs ensured that no agglomeration occurred for up to 60 days. The antioxidant activity of M-AgNPs was evaluated by 1,1-diphenyl-2-trinitrophenylhydrazine (DPPH) assay, and the DPPH radical clearance rate of M-AgNPs was up to about 79%. Greenly synthesized M-AgNPs exhibited better antibacterial activity than chemically synthesized commercial silver nanoparticles (C-AgNPs), due to the active molecules attached to their surfaces. The inhibition zone diameters of M-AgNPs against P.aeruginosa, E.coli and S.aureus were 13.9±0.4、12.2±0.3、12.8±0.7 mm, respectively. Such greenly synthesized AgNPs from medicinal plants have good prospects in the field of biomedicine.
REVIEW | doi:10.20944/preprints202311.0732.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Salmonella Typhi; Typhoid Fever; Fimbriae; Vaccine; Antibacterial Agent; Drug Target
Online: 13 November 2023 (10:04:43 CET)
Despite recent public health and hygiene advancements, enteric fever, commonly referred to as typhoid fever, remains a common disease in developing nations. The common mode of infection is contaminated water or food. Additionally, person-to-person transmission through poor hygiene and sewage contamination of water supplies has been blamed for most outbreaks. The exact burden of typhoid has yet to be discovered because of the lack of surveillance systems in many developing nations. This makes it difficult to estimate the number of cases. Recent studies have shown that the actual number of cases of typhoid has been estimated to be around 21.6 million annually. The mortality studies suggest that the incidence of typhoid is highest in children under five years old. Typhoid fever and paratyphoid fever have been demonstrated to be life-threatening illnesses. Salmonella serotype Typhi (S. Typhi) is the causative organism of typhoid fever whereas Salmonella serotype Paratyphi is the causative organism for paratyphoid fever. The S. Typhi bacterium is known to be resistant to various drugs. There is a dire need to develop new drugs to treat and overcome the current drug-resistant S. Typhi. The identification of new targets marks the beginning of the process of developing new anti-S. Typhi drugs. The S. Typhic genome sequencing and recent cutting-edge molecular biology tools have led to the discovery of numerous new inhibitors and targets. The goal of this review is to identify the most critical targets in the S. Typhi that are targeted by drugs. It also highlights the various promising vaccines on the market or are still in preclinical studies. A detailed understanding of the targets could help researchers develop safer and more efficient antibacterial agents against S. Typhi.Additionally, the advancement of molecular techniques and the knowledge of the Salmonella pathogenesis pathways have opened better avenues to develop effective antibiotics and vaccines against this pathogen. This review also sought to identify and summarize critical structures of this pathogen that play significant roles in the maturation, development, and pathogenesis of S. Typhi. The endpoint of this work is to provide valuable information on potential therapeutic targets of S. Typhi for drug and vaccine developers.
ARTICLE | doi:10.20944/preprints202311.0495.v1
Subject: Public Health And Healthcare, Public Health And Health Services Keywords: Antibacterial; Food handlers; Nasal carriage; Staphylococcus aureus; Sana’a restaurants; Yemen
Online: 8 November 2023 (07:26:18 CET)
Background: Staphylococcus aureus is a ubiquitous organism that normally colonizes the human body and causes food poisoning. Aim: This study aimed to determine the rate of nasal carriage of S. aureus among food handlers in Sana’a restaurants in, Yemen and performed an antibacterial susceptibility test. Methods: This cross-sectional study was carried out among healthy food handlers from November 2022 to March 2023. Approximately 420 nasal swabs were collected and S. aureus was isolated and identified according to standard bacteriological procedures. Moreover, the antibacterial susceptibility pattern was determined using the disc diﬀusion method. Additionally, the required data were obtained by using the pretested questionnaire. Results: Of 420 nasal swabs, 78 (18.6%) food handlers were S. aureus nasal carriers. The prevalence rate of S. aureus was significantly higher among subjects aged >30 years (23.1%), males (18.8%), and uneducated subjects (25%). Additionally, a higher rate of S. aureus nasal carriers was observed among food handlers who worked as cooks (19.4%), had less than 2 years of experience (20.5%), and had low hygiene (29%). The S. aureus isolates were sensitive to ciprofloxacin (71.8%), vancomycin (76.9%), and amoxicillin-clavulanic acid (61%). Conversely, the isolated S. aureus was resistant to oxacillin (69.2%) and methicillin (66.7%). Conclusion: These data stress that food handlers with a high S. aureus nasal carrier rate may pose significant risks to consumers. Therefore, creating restaurant policies and rules is necessary to provide safe and healthy food to consumers.
ARTICLE | doi:10.20944/preprints202311.0335.v1
Subject: Chemistry And Materials Science, Biomaterials Keywords: poly-3-hydroxybutyrate; chlorophyll derivatives; electrospinning; antibacterial properties; supramolecular structure
Online: 7 November 2023 (02:49:38 CET)
Biomimetic materials are substances that replicate natural structures. There are several methods for producing such materials with highly developed surfaces from a wide range of polymers, but electrospinning is of particular interest due to its simplicity of implementation and the ability to modify the produced fibrous materials resembling structures found in living organisms. This study explores new biomimetic materials based on polyhydroxyalkanoates, specifically poly-3-hydroxybutyrate, modified with chlorophyll derivatives. The research investigates the impact of chlorophyll derivatives on the morphology, supramolecular structure, and key properties of nonwoven materials. The obtained results are of interest for the development of new biomimetic environmentally friendly materials for biomedicine with special properties.
ARTICLE | doi:10.20944/preprints202311.0078.v1
Subject: Medicine And Pharmacology, Dentistry And Oral Surgery Keywords: Root canal system; antibacterial; irrigants; Thyme Essential Oil; Sodium Hypochlorite
Online: 1 November 2023 (13:13:03 CET)
Irrigation is crucial in cleaning and disinfection of the root canal system, because endodontic instruments are unable to reach a large part of the root canal system (isthmuses, accessory canals, apical ramifications) and bacteria that can reside. Sodium hypochlorite (NaOCl) is currently used as irrigant in root canal therapies for its non-specific protheolytic and antimicrobial properties, but undesirable effects may be observed especially when used near the terminus of apical foramen. This study aims to evaluate antimicrobial properties of Thyme Essential Oil (TEO) used alone or in combination with NaOCl against different bacterial strains, especially Staphylococcus aureus and Streptococcus mutans. TEO non-cytotoxic concentration (9,28mg/mL) showed antimicrobial properties comparable to NaOCl after 1min of contact, both in presence of organic material (6% sheep blood). Moreover, the combination of TEO and NaOCl did not compromise their individual antimicrobial properties at the same time of contact. These data suggest that TEO could be used as antimicrobial irrigant in root canal therapies in association with NaOCl, to reduce concentration of NaOCl and its undesirable side effects. Due to the absence of cytotoxic effects at tested dilution, TEO could be safely used also near the terminus of apical foramen for its cytocompatibility.
ARTICLE | doi:10.20944/preprints202310.1025.v1
Subject: Engineering, Chemical Engineering Keywords: Colloidal heterostructures; functional aerogels; Cellulose Nanofibers; CuO nanoparticles; Antibacterial Membranes
Online: 17 October 2023 (05:18:59 CEST)
The involved components of formulated blending, CNF and CuO NPs, were individually obtained by using a biorefinery strategy for agricultural waste valorization together with an optimized chemical precipitation, assisted by ultrasounds. The optimization of synthesis parameters for CuO NPs have avoided the presence of undesirable species which usually requires of later thermal treatment with associated costs. The aerogels-based structure, obtained by conventional freeze-drying, acted as 3D support for CuO NPs providing a good dispersion within the cross-linked structure of the nanocellulose and facilitating direct contact of the antibacterial phase against undesirable microorganisms. All samples showed a positive response against Escherichia coli and Staphylococcus aureus. An increase of the antibacterial response of the aerogels, measured by agar disk diffusion test, has been observed with the increase of CuO NPs incorporated, obtaining width of the antimicrobial “halo” (nwhalo) from 0 to 0.6 and 0.35 for S. aureus and E. coli, respectively. Furthermore, the aerogels have been able to deactivate S. aureus and E. coli in less than 5 hours when the antibacterial assays have been analyzed by broth dilution method. From CNF-50CuO samples, an overlap nanoparticles effect produced a decrease of the antimicrobial kinetic.
ARTICLE | doi:10.20944/preprints202307.1339.v1
Subject: Biology And Life Sciences, Ecology, Evolution, Behavior And Systematics Keywords: Ebenus pinnata; climate; morphology; pollen; meiosis; chromosomes; antioxidants; antibacterial activity
Online: 20 July 2023 (02:28:26 CEST)
The North African E. pinnata is not known as a traditional medicinal plant but modern research has revealed its extracts richness in anti-oxidants and components of medicinal value. Despite its wide distribution and medicinal value, the species remains taxonomically and phytochemically un-derstudied, especially in Algeria. Here we compare three ecotypes of E. pinnata from the humid, sub-humid and semi-arid areas. The comparison was carried out using classical techniques of multivariate plant morphology, pollen grains size and shape, chromosome numbers, pollen fer-tility, anti-oxidant and antibacterial activities. Significant differences were revealed for all criteria except pollen fertility and antibacterial activity. The semi-arid ecotype showed to be a remote group in relation to the two others except for pollen size where the remote group was the sub-humid ecotype. Pollen size appeared positively correlated with karyotype length. The results (mg GAE/g EXT) of the antioxidant activity tests of the “humid”, “sub-humid” and the “semi-arid” plant groups are as follows, respectively; TPC: 50.79±0.51, 52.04±1.05 and 56.89±0.46; DPPH: 71.18±2.24, 86.39±3.02 and 95.67±2.02; RP: 11.09±1.24, 17.21±0.75 and 25.88±0.26. The inhibition area diameter in the antibacterial activity test varied from 9.25±1.06 mm (Semi-arid plants vs Pseudo-monas aeruginosa) to 12.00±1.41 mm (Sub-humid plants vs Escherichia coli).
ARTICLE | doi:10.20944/preprints202307.0286.v1
Subject: Medicine And Pharmacology, Pharmacology And Toxicology Keywords: human hemoglobin; bovine hemoglobin; bioactive peptides; antibacterial activity; antioxidant activity
Online: 6 July 2023 (02:12:27 CEST)
This study focuses on the enzymatic hydrolysis of hemoglobin, the main component of cruor that gives blood its red color in mammals. The antibacterial and antioxidant potential of human hemoglobin hydrolysates were evaluated in comparison to bovine hemoglobin. The results showed strong antimicrobial activity of the peptide hydrolysates against six bacterial strains, independent of the initial substrate concentration level. The hydrolysates also showed strong antioxidant activity measured by four different tests. In addition, the antimicrobial and antioxidant activity of the human and bovine hemoglobin hydrolysates showed little or no significant difference, with only the concentration level being the determining factor in their activity. The results of the mass spectrometry study showed the presence of a number of bioactive peptides, the majority of which have characteristics similar to those mentioned in the literature. New bioactive peptides were also identified in human hemoglobin, such as antibacterial peptides PTTKTYFPHF (α37-46), FPTTKTYFPH (α36-45), TSKYR (α137-141) and STVLTSKYR (α133-141), as well as an antioxidant TSKYR (α137-141). According to these findings, human hemoglobin represents a promising source of bioactive peptides beneficial to the food or pharmaceutical industries.
ARTICLE | doi:10.20944/preprints202307.0022.v1
Subject: Chemistry And Materials Science, Nanotechnology Keywords: Silver/zinc oxide nanoparticles; Semiconductor; Microbial biosynthesis; Photodegradation; Cytotoxicity; Antibacterial
Online: 3 July 2023 (08:37:44 CEST)
The biological synthesis of nanoparticles has been emerging as an environmentally benign and eco-friendly method owing to its cost-effectiveness and high efficiency. Recently, the biological synthesis of semiconductor and metal-doped semiconductor nanoparticles with enhanced photocatalytic degradation efficiency and anticancer and antibacterial properties have gained tremendous attention. In pursuit of this purpose, for the first time, we biosynthesized zinc oxide (ZnO) and silver/ZnO nanocomposites (NCs) as semiconductor and metal-doped semiconductor nanoparticles, respectively, using the cell-free filtrate (CFF) of Lysinibacillus sphaericus bacterium. The biosynthesized ZnO and Ag/ZnO were characterized by various techniques such as ultraviolet-visible spectroscopy, X-ray diffraction, Fourier-transform Infrared spectroscopy, Field-emission scanning electron microscopy, transmission electron microscopy, and photoluminescence spectroscopy. The photocatalytic degradation potential of these semiconductor/metal-semiconductor nanoparticles was evaluated against the degradation of azo dye methylene blue (MB) under simulated solar irradiation. Ag/ZnO showed 90.7 ± 0.91% photocatalytic degradation of MB, compared to 50.7 ± 0.53% by ZnO in 120 min. The cytotoxicity of ZnO and Ag/ZnO on human cervical HeLa cancer cells was determined using an MTT assay. Both nanomaterials exhibited cytotoxicity in a concentration-dependent and time-dependent manner on HeLa cells. The antibacterial activity was also determined against Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus). Compared to ZnO, Ag/ZnO NPs showed higher antibacterial activity. Hence, the biosynthesis of semiconductor nanoparticles could be a promising strategy for developing hybrid metal/semiconductor nanomaterials for different biomedical and environmental applications.
ARTICLE | doi:10.20944/preprints202305.1546.v1
Subject: Chemistry And Materials Science, Organic Chemistry Keywords: Oleanolic acid; phtalimidines; triazole; click chemistry; antibacterial activity; molecular docking
Online: 23 May 2023 (03:33:09 CEST)
As part of valorisation of agricultural waste into bioactive compounds, a series of structurally novel oleanolic acid ((3β-hydroxyolean-12-en-28-oic acid, OA-1)-phtalimidines (isoindolinones) conjugates 18a-v bearing 1,2,3-triazole moieties were designed and synthesized by treating a previously azide 4 prepared from OA-1 isolated from olive pomace (Olea europaea L.) with a wide range of propargylated phtalimidines using the Cu(I)-catalyzed click chemistry approach. OA-1 and its newly prepared analogues 18a-v were screened in vitro for their antibacterial activity against two Gram-positive bacteria, Staphylococcus aureus and Listeria monocytogenes; and two Gram-negative bacteria, Salmonella thyphimurium and Pseudomonas aeruginosa. Attractive results were obtained notably against L. monocytogenes. Compounds 18d, 18g and 18h exhibited the highest antibacterial activity when compared with OA-1 and other compounds in the series against tested pathogenic bacterial strains. Molecular docking study was performed to explore the binding mode of the most active derivatives against the target protein from L. monocytogenes. Results showed the importance of both hydrogen bonding and hydrophobic interactions with the target protein and are in favor to the experimental data.
ARTICLE | doi:10.20944/preprints202303.0266.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: drug resistance; flavonoids; RNA-seq; Klebsiella pneumoniae; Rutin; antibacterial agents
Online: 15 March 2023 (02:03:17 CET)
The emergence of drug resistant pathogenic bacteria is increasingly challenging conventional antibiotics. Plant derived flavonoids are considered as potential alternatives to antibiotics due to their antimicrobial properties. However, the mechanisms by which flavonoids modulate pathogenic microorganisms’ growth are not fully understood. In our previous studies we found that Rutin, a kind of flavonoids showed inhibition against Klebsiella pneumoniae strains. In order to better understand its inhibitory mechanism on strain growth, we used both Rutin and Luteolin as treatments to incubate K. pneumoniae ATCC700603 strain. After incubation for 4 hours, the homogenous and differential effects of two different flavonoids on the growth of K. pneumoniae were evaluated. The integrated metabolomic and transcriptomic analysis was performed. The expression levels of 5,483 genes and the contents of 882 metabolites were measured. The differentially expressed genes (DEGs) and metabolites (DEMs) were screened and analyzed. The correlation between DEGs and DEMs were also studied. Our results showed that Rutin could inhibit the strain growth by changing metabolic pathways and ABC transporters pathways. Our study also revealed FU841_RS17580 and FU841_RS19145 as functional genes that played vital roles in the strain growth.
ARTICLE | doi:10.20944/preprints202212.0486.v1
Subject: Chemistry And Materials Science, Organic Chemistry Keywords: Terminalia arjuna; Terminalone A; flavonoids; antibacterial; antioxidants; reactive oxygen specie
Online: 26 December 2022 (11:02:19 CET)
Terminalia arjuna possesses significant cardio protective, antidiabetic and antioxidant properties as these properties are described in Ayurveda. In the present study, three flavonoids were isolated through the separation and chromatographic purification of the whole plant material of T. arjuna. Spectroscopic characterization identified one of them as a new flavonoid “Terminalone A (1)” and two known flavonoids i.e. 6-hydroxy-2-(4-hydroxyphenyl)-7-methoxy-4H-chromen-4-one (2) and 2-(3,4-dihydroxyphenyl)-5,7-dihydroxy-4H-chromen-4-one (3). The bioactivity studies showed considerable antibacterial and antioxidant (DPPH was used as a scavenger) potential for all the three compounds 1-3 where the compound 1 showed strong antibacterial and antioxidant activity.
ARTICLE | doi:10.20944/preprints202211.0370.v1
Subject: Chemistry And Materials Science, Food Chemistry Keywords: hen egg white lysozyme; chemical modification; antibacterial activity; secondary structure
Online: 21 November 2022 (04:40:14 CET)
Egg white lysozyme was modified by chemical methods using organic acids. Caffeic acid and p-coumaric acid in organic acids were used as modifiers, and 1-Ethyl-3- (3-dimethylaminopropyl) carbodiimide hydrochloride and N-hydroxy succinimide were used as dehydration condensation agents during modification. A certain degree of modified lysozyme was obtained through appropriate modification conditions. The antibacterial properties and structure of the obtained two organic acid modified lysozymes were compared with natural enzymes. The results showed that compared with the natural enzyme, the activity of modified lysozyme decreased, but the inhibitory effect on Gram-negative bacteria was enhanced. The minimum inhibitory concentrations of caffeic acid modified enzyme and p-coumaric acid modified enzyme on Escherichia coli and Pseudomonas aeruginosa were 0.5 mg/mL and 0.75 mg/mL, respectively. However, the antibacterial ability of modified lysozyme to Gram-positive bacteria was lower than that of natural enzyme. The minimum inhibitory concentration of caffeic acid modified enzyme and p-coumaric acid modified enzyme to Staphylococcus aureus and Bacillus subtilis was 1.25 mg/mL. The peak fitting results of the amide-I band (1600 cm-1-1700 cm-1) absorption peak in the infrared spectroscopy showed that the content of the secondary structure of the two modified enzymes obtained after modification was different from that of natural enzymes.
ARTICLE | doi:10.20944/preprints202104.0311.v1
Subject: Chemistry And Materials Science, Biomaterials Keywords: Chitosan; Silver nanoparticles; Graphene oxide; Nanocomposites; Antibacterial property; Drug delivery
Online: 12 April 2021 (13:59:44 CEST)
In this work, we designed and fabricated a multifunctional nanocomposite system which consists of chitosan, raspberry-like silver nanoparticles and graphene oxide. Room temperature atmospheric pressure microplasma (RT-APM) process provides a rapid, facile, and environment-friendly method for introducing silver nanoparticles into the composite system. By loading different drugs onto the polymer matrix and/or graphene oxide, our composite can achieve a pH controlled dual drug release with release profile specific to the drugs used. In addition to its strong antibacterial ability against E. coli and S. aureus, our composite also demonstrates excellent photothermal conversion effect under irradiation of near infrared lasers. These unique functionalities point to it’s the potential of nanocomposite system in multiple applications areas such as multimodal therapeutics in healthcare, water treatment, and anti-microbial, etc.
ARTICLE | doi:10.20944/preprints202102.0245.v1
Subject: Chemistry And Materials Science, Biomaterials Keywords: Mesoporous Bioactive Glass Nanopartciles; Sol-Gel; Antibacterial Activity; Silver; Bioactivity
Online: 10 February 2021 (07:54:28 CET)
Biomedical implants are the need of this era due to the increase in number of accidents and follow-up surgeries. Different types of bone diseases such as osteoarthritis, osteomalacia, bone cancer, etc. are increasing globally. Mesoporous bioactive glass nanoparticles (MBGNs) are used in biomedical devices due to their osteointegration and bioactive properties. In this study, silver (Ag) and strontium (Sr) doped mesoporous bioactive glass nanoparticles (Ag-Sr MBGNs) were prepared by a modified Stöber process. In this method, Ag+ & Sr2+ were co-substituted in pure MBGNs to harvest the antibacterial properties of Ag ions, as well as pro-osteogenic potential of Sr2 ions. The effect of the two ion concentration on morphology, surface charge, composition, antibacterial ability, and in-vitro bioactivity was studied. Scanning electron microscopy (SEM), X-Ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) confirmed the doping of Sr and Ag in MBGNs. SEM and EDX analysis confirmed the spherical morphology and typical composition of MBGNs, respectively. The Ag-Sr MBGNs showed a strong antibacterial effect against Staphylococcus carnosus and Escherichia coli bacteria determined via turbidity and disc diffusion method. Moreover, the synthesized Ag-Sr MBGNs develop apatite-like crystals upon immersion in simulated body fluid (SBF), which suggested that the addition of Sr improved in-vitro bioactivity. The Ag-Sr MBGNs synthesize in this study can be used for the preparation of scaffolds or as a filler material in the composite coatings for bone tissue engineering.
ARTICLE | doi:10.20944/preprints202012.0013.v1
Subject: Chemistry And Materials Science, Analytical Chemistry Keywords: Thermolysin; Antibacterial agents; Docking; Molecular dynamics; MM-PBSA, ADME-Tox.
Online: 1 December 2020 (10:48:09 CET)
The search for new antibacterial agents that could decrease bacterial resistance is a subject that is continuously developing. The Gram-negative and Gram-positive bacteria have a metalloproteins group belonging to the M4 family. That is the main virulence factor of these bacteria. In this work, we have used a computational protocol based on the comprehensive analysis of the results of docking, molecular dynamics simulation, MM-PBSA, ligand efficiency, and ADME-Tox properties of ligand designed in silico in the previous manuscript using the Thermolysin from Bacillus thermoproteolyticus, a metalloprotein of the M4 family as a target. The principal results obtained were the designed ligands were adequately oriented in the thermolysin active center. The Lig783, Lig2177, and Lig3444 compounds were those with better dynamic behavior, however, when analyzing the results extracted from the ADME-Tox properties, only Lig783 was the best antibacterial agent candidate.
ARTICLE | doi:10.20944/preprints202008.0524.v1
Subject: Chemistry And Materials Science, Organic Chemistry Keywords: Isoxazolines; nitrile oxide; 1,3-dipolar cycloaddition; antibacterial activity; antioxidant activity
Online: 24 August 2020 (10:03:22 CEST)
A series of derivatives of trans-3-(2,4,6-trimethoxy phenyl)-4,5-dihydro isoxazolo-4,5-bis(aroylcarbohydrazide) and of trans-3-(2,4,6-trimethoxyphenyl)4,5-dihydroisoxazolo-4,5-bis[carbonyl-(4’phenyl)thiosemi- carbazide (9) were synthesized from trans-3-(2,4,6-trimethoxyphenyl)-4,5-dihydro-4,5-bis(hydrazenocarbonyl) Isoxazole (8). The structures of the Compounds were elucidated by elemental and spectral (IR, NMR, and MS) analysis. The compound 9 show activity against some bacterial species. Whereas, no activity was observed for compounds 10a, 10b and 10c against all bacterial species. The antioxidant activity of new compounds has been screened. Compound 9 showed higher antioxidant activity using the DPPH and ATBS method.
REVIEW | doi:10.20944/preprints202008.0291.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Advanced Oxidation Process, Antibacterial resistance, Disinfection, Persistence, ROS, Stress response
Online: 13 August 2020 (06:15:17 CEST)
Different water treatment regiments are revealed to have potential in enriching antibiotic resistant bacteria (ARB). Advanced oxidation processes (AOPs) based disinfection techniques have been studied widely in the recent times due to their advantages over conventional treatment methods. However, bacterial response and adaptations against the hostile environments of AOPs is not clearly understood yet. Based on the existing knowledge on the ways in which bacteria surpass the antibiotic treatment, here we propose few important aspects of bacterial adaptation which could be true for AOPs as well since both antibiotics and AOPs generate reactive oxygen species (ROS) during their modes of action. We discuss the plausible role of ROS in the selection of ARB and bacterial heterogeneity as a strategy to bypass the lethal action of AOPs. Understanding bacterial adaptation during disinfection plays a vital role in devising strategies to outclass the bacterial survival. Hence, more importance should be given to such studies in the near future for the successful implementation of AOPs.
ARTICLE | doi:10.20944/preprints202007.0223.v1
Subject: Chemistry And Materials Science, Nanotechnology Keywords: Iron oxides; nanoparticles; organic dye degradation; photocatalytic effect; antibacterial behavior
Online: 11 July 2020 (03:38:48 CEST)
Currently, the use of sustainable chemistry as an ecological alternative for the generation of products or processes, free of polluting substance has assumed a preponderant role. The aim of this work is propose a bioinspired, facile, at low cost, non-toxic and environmentally friendly alternative to obtaining magnetic nanoparticles whit a majority phase of magnetite (Fe3O4). Is important to empathize that the synthesis was based on the chemical reduction through the Cnicus Benedictus extract, whose use as reducing agent has not been reported in the synthesis of iron oxides nanoparticles. In addition, the Cnicus Benedictus is abundant endemic plant in Mexico, with several medicinal properties and a large number of natural antioxidants. The obtained nanoparticles exhibited significant magnetic and antibacterial properties and an enhanced photocatalytic activity. The crystallite size of the Fe3O4 nanoparticles (Fe3O4 NP’s) was calculated by Williamson-Hall method. The photocatalytic properties of the Fe3O4 NP´s were studied by kinetics absorptions models in the Congo red (CR) degradation. Finally the antibacterial effect of the Fe3O4 NP´s were evaluated mediated the Kirby-Bauer method against E. coli and S. aureus bacteria. This route offers a green alternative to obtain Fe3O4 NP´s with remarkable magnetic, photocatalytic and antibacterial properties.
ARTICLE | doi:10.20944/preprints202006.0219.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: tetrasubsituted imidazoles; synthesis; cyclocondensation reaction; characterization; antibacterial activity; compound K2
Online: 17 June 2020 (13:18:37 CEST)
A new class of tetrasubstituted imidazole based compounds was synthesized using a multicomponent one-pot synthesis scheme through a cyclo condensation reaction of benzil, aromatic primary amines, aldehydes and ammonium acetate in glacial acetic acid. The synthesized compounds have been analyzed and characterized by melting point, color, conductivity method, CHN analysis, FT-IR, and UV-Visible. The reaction proceeding was examined by TLC after regular intervals of period. To test biological activity, the synthesized compounds have been examined against various bacterial strains. From the analysis of the antibacterial activity of these synthesized compounds demonstrated that all three imidazole compounds have considerable to significant activity against the strains, and compound K2 was found potent comparatively.
REVIEW | doi:10.20944/preprints202004.0416.v1
Subject: Medicine And Pharmacology, Other Keywords: citation classics; top-cited articles; antibiotics; bibliometric analysis; antibacterial; antimicrobials
Online: 23 April 2020 (15:20:39 CEST)
Citation frequencies represent the most significant contributions in any respective field. This bibliometric analysis aimed to identify and analyze the 100 most-cited publications in the field of antibiotics and to highlight the trends of research in this field. “All databases” of Clarivate Analytics' Web of Science was used to identify and analyze the 100 publications. The articles were then cross-matched with Scopus and Google Scholar. The frequency of citation ranged from 940 to 11051 for the Web of Science, 1053 to 10740 for Scopus, and 1162 to 20041 for Google Scholar. Five hundred thirteen authors made contributions to the ranked list, and Robert E.W. Hancock contributed in six articles, which made it to the ranked list. Sixty-six scientific contributions originated from the United States of America. In contrast, five publications were linked to the University of Manitoba, Canada, that was identified as the educational organization, which made the most contributions (n=5). According to the methodological design, 26 of the most cited works were review-type closely followed by 23 expert opinions/perspectives. Eight articles were published in Nature journal, making it the journal with the most scientific contribution in this field. Correlation analysis between the publication age and citation frequency was found statistically significant (P = .012).
Subject: Chemistry And Materials Science, Chemical Engineering Keywords: polyethylene; nanocomposites; silver nanoparticles; Fe3O4-Ag hybrid nanoparticles; antibacterial activity
Online: 19 March 2019 (07:54:54 CET)
We report here the synthesis of uniform nanospheres-like silver nanoparticles (AgNPs, 5-10 nm) and the dumbbell-like Fe3O4-Ag hybrid nanoparticles (FeAgNPs, 8-16 nm) by the use of seeding growth method in the presence of oleic acid (OA)/oleylamine (OLA) as surfactants. The antibacterial activity of pure nanoparticles and nanocomposites by monitoring the bacterial lag–log growth has been investigated. The electron transfer from AgNPs to Fe3O4NPs which enhances the biological of silver nanoparticles has been proven by nanoscale Raman spectroscopy. The lamellae structure in the spherulite of FeAgNPs/PE nanocomposites seems play the key role to the antibacterial activity of nanocomposites, which has been proven by nanoscale AFM-IR. An atomic force microscopy coupled with nanoscale infrared microscopy (AFM-IR) is use to highlight the distribution of nanoparticles on the surface of nanocomposite at the nanoscale. The presence of FeAgNPs in PE nanocomposites has a better antibacterial activity than that reinforced by AgNPs due to the faster Ag+ release rate from the Fe3O4-Ag hybrid nanoparticles and the ionization of AgNPs in hybrid nanostructure.
ARTICLE | doi:10.20944/preprints201809.0373.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: antibacterial; channel catfish; columnaris disease; Flavobacterium columnare; stilbenes; muscadine; pyranoanthocyanin
Online: 19 September 2018 (08:32:39 CEST)
Enteric septicemia of catfish, columnaris disease, and streptococcosis, caused by Edwardsiella ictaluri, Flavobacterium columnare, and Streptococcus iniae, respectively, are the most common bacterial diseases of economic significance for the pond-raised channel catfish Ictalurus punctatus industry. Several management practices are used by catfish farmers to prevent large financial losses from these diseases such as the use of commercial antibiotics and other chemicals. In order to discover environmentally benign alternatives, using a rapid bioassay, we evaluated a crude extract from the roots of muscadine Vitis rotundifolia against these fish pathogenic bacteria and determined that the extract was most active against F. columnare. Subsequently, several isolated compounds from the root extract were further evaluated against F. columnare. Among these isolated compounds, (+)-hopeaphenol (2) and (+)-vitisin A (3) were found to be the most active against F. columnare, with 24-h 50% inhibition concentrations of 4.0±0.7 and 7.7±0.6 mg/L, respectively, and minimum inhibitory concentrations of 9.1±0 mg/L for each compound. Efficacy testing of 2 and 3 is necessary to further evaluate the potential for these compounds to be used as antibacterial agents for managing columnaris disease.
ARTICLE | doi:10.20944/preprints201806.0489.v1
Subject: Chemistry And Materials Science, Biomaterials Keywords: antibacterial agent; antibiofilm; ferulic acid grafted chitosan; human pathogenic bacteria
Online: 29 June 2018 (15:21:41 CEST)
Emergence of more virulent forms of human pathogenic bacteria with multi drug resistance is a serious global issue and requires alternative control strategies. The current study was focused to investigate the antibacterial and antibiofilm potential of ferulic acid grafted chitosan (CFA) against Listeria monocytogenes (LM), Pseudomonas aeruginosa (PA), and Staphylococcus aureus (SA). The present result showed that CFA at 64 µg/mL concentration exhibit bactericidal action against LM and SA (>4 log reduction) and bacteriostatic action against PA (<2 log CFU) within 24 h of incubation. Further studies based on propidium iodide uptake assay, measurement of material released from the cell, and electron microscopic analysis revealed that the bactericidal action of CFA was due to the altered membrane integrity and permeability. CFA dose-dependently inhibited biofilm formation (52-89% range), its metabolic activity (30.8-75.1% range) and eradicated mature biofilms, and reduced viability (71-82% range) of the test bacteria. Also, the swarming motility of LM was differentially affected at sub-MIC concentration of CFA. In the present study, the ability of CFA to kill and alter the virulence production in human pathogenic bacteria will insight a new scope for the application of these biomaterials in healthcare to effectively treat bacterial infections.
ARTICLE | doi:10.20944/preprints201806.0005.v1
Subject: Chemistry And Materials Science, Organic Chemistry Keywords: peptoids; peptoid-peptide hybrid; nisin; antibacterial; alkyne-azide click reactions
Online: 1 June 2018 (06:18:06 CEST)
Antimicrobial peptides and structurally related peptoids offer potential for the development of new antibiotics. However, progress has been hindered by challenges presented by poor in vivo stability (peptides) or lack of selectivity (peptoids). Herein, we have developed a process to prepare novel hybrid antibacterial agents that combine both linear peptoids (increased in vivo stability compared to peptides) and a nisin fragment (lipid II targeting domain). The hybrid nisin-peptoids prepared were shown to have low µM activity (comparable to natural nisin) against methicillin-resistant Staphylococcus aureus.
ARTICLE | doi:10.20944/preprints201803.0050.v1
Subject: Chemistry And Materials Science, Medicinal Chemistry Keywords: carboxamide; carbohydrazine; antibacterial; antifungal; molecular docking; Schiff base; NMR; IR
Online: 7 March 2018 (05:11:10 CET)
The article describes facile one-pot, hi-yielding reactions to synthesize substituted 3,4-dimethyl-1H-pyrrole-2-carboxamide (3a–m) and carbohydrazide analogues (5a–l) as potential antifungal and antimicrobial agents. The structural integrity and purity of the synthesized compounds were assigned based on appropriate spectroscopic techniques. Synthesized compounds were assessed in vitro for antifungal and antibacterial activity. The compound 5h, 5i and 5j were found to be the most potent against A. fumigatus, with MIC value of 0.031 mg/mL. The compound 5f bearing a 2,6-dichloro group on the phenyl ring was found to be the most active broad spectrum antibacterial agent with MIC value of 0.039 mg/mL. The mode of action of the most promising antifungal compounds (one representative from each series; 3j and 5h) was established by their molecular docking to the active site of sterol 14α-demethylase. Molecular docking studies revealed a highly spontaneous binding ability of the tested compounds in the access channel away from catalytic heme iron of the enzyme, which suggested that the tested compounds inhibit this enzyme and would avoid heme iron related deleterious side effects observed with existing antifungal compounds.
ARTICLE | doi:10.20944/preprints201704.0076.v1
Subject: Biology And Life Sciences, Agricultural Science And Agronomy Keywords: acne vulgaris; antibiotic resistance; chitosan-phytochemical conjugates; synergistic antibacterial effect
Online: 13 April 2017 (11:19:33 CEST)
The object of this study was to discover an alternative therapeutic agent with fewer side effects against acne vulgaris, which is one of the most common skin diseases. Acne vulgaris often associates with acne-related bacteria such as <i>Propionibacterium acnes</i>, <i>Staphylococcus epidermidis</i>, <i>Staphylococcus aureus</i> and <i>Pseudomonas aeruginosa</i>, some of which exhibit a resistant against commercial antibiotics used in the treatment of acne vulgaris (tetracycline, erythromycin, and lincomycin). In the current study, we evaluated <i>in vitro</i> antibacterial activity of chitosan-phytochemical conjugates against acne-related bacteria. Three of chitosan-phytochemical conjugates used in this study showed stronger antibacterial activity than that of chitosan (unmodified control). Chitosan-caffeic acid conjugate (CCA) exhibited the highest antibacterial activity against acne-related bacteria with minimum inhibitory concentration values of 8 μg/mL to 256 μg/mL. In addition, the MICs of antibiotics against antibiotic resistant <i>P. acnes</i> and <i>P. aeruginosa</i> strains were dramatically reduced in the combination with CCA, suggesting that CCA would restore the antibacterial activity of the antibiotics. The analysis of fractional inhibitory concentration indices clearly revealed a synergistic antibacterial effect between CCA and the antibiotics. Thus, the median ∑FIC values against the antibiotic resistant bacterial strains were ranged from 0.375 to 0.533 in the combination mode of CCA and antibiotics.
ARTICLE | doi:10.20944/preprints202311.0140.v1
Subject: Medicine And Pharmacology, Medicine And Pharmacology Keywords: Electrospinning; Polysaccharides; Antibacterial; Cancer treatment; Core-shell nanofibers, Drug delivery systems
Online: 2 November 2023 (09:12:20 CET)
This article discusses the fabrication of pullulan/polyvinyl alcohol (PVA) and PVA blends as carrier polymers for drug delivery. This study utilized coaxial electrospinning to encapsulate doxorubicin (DOX), a common anticancer drug, within nanofibers, which helped mitigate the adverse effects of DOX on normal cells. The study also demonstrated that the coaxial electrospinning technique using PVA/pullulan cores was effective in inhibiting the attachment and proliferation of HeLa cells, a type of cervical cancer cell. The use of pullulan/PVA and PVA blends as carrier polymers in conjunction with coaxial electrospinning could provide a safe and effective drug delivery system for the treatment of cervical and other solid malignancies. The study concluded that nanofibers showed promising results in inhibiting the growth of HeLa cells, indicating their potential as safe and effective drug delivery systems for treating cervical cancer and other solid malignant tumors.