ARTICLE | doi:10.20944/preprints202001.0157.v3
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: pectin; antioxidant; lemon; flavonoids; hydrodynamic cavitation; IntegroPectin
Online: 31 March 2020 (05:00:13 CEST)
Lemon pectin extracted along with water-soluble flavonoids and other phytochemicals from citrus industry’s waste lemon peel via hydrodynamic cavitation in water, directly at pre-industrial scale and further isolated via freeze drying, shows exceptionally high antioxidant and non-cytotoxic activity. Preliminary investigation indicates also significant antimicrobial activity. These findings open the route to the development of new nutraceutical and healthcare application of a versatile biopolymer endowed with new functionality, rapidly and conveniently obtained from an abundant by-product of the agrofood industry.
ARTICLE | doi:10.20944/preprints202310.0983.v1
Subject: Biology And Life Sciences, Plant Sciences Keywords: bioestimulant; flavonoids; tomato; hormones; RNA-seq
Online: 16 October 2023 (15:36:48 CEST)
The exogenous application of phenolic compounds is increasingly recognized as a valuable strategy for promoting growth and mitigating the adverse effects of abiotic stress. However, the biostimulant effect under optimal conditions have not been thoroughly explored. In this study, we investigated the impact of foliar application of flavonoids, specifically Crop Bio Life (CBL), on tomato plants grown under controlled conditions. Our study focused on determining growth parameters, such as cell size, and assessing the concentration of hormones. Principal component analysis (PCA) from all physiological variables were determined. Additionally, we utilized high-throughput mRNA sequencing technology and bioinformatic methodologies to robustly analyze the transcriptomes of tomato leaves regulated by flavonoids. The findings revealed that CBL primarily influenced cells enlargement, leading to increased growth. Furthermore, CBL-treated plants exhibited higher concentrations of the hormone zeatin but lower concentrations of IAA. Moreover, RNAseq analysis indicated that CBL-treated plants required increased mineral transport and water uptake, as evidenced by gene expression patterns. Genes related to pathways such as fatty acid degradation, phenylpropanoid biosynthesis, and ABC transporters showed regulatory mechanisms governing internal flavonoid biosynthesis, transport, and tissue concentration, ultimately resulting in higher flavonoid concentrations in tomato leaves.
ARTICLE | doi:10.20944/preprints202306.2017.v1
Subject: Environmental And Earth Sciences, Environmental Science Keywords: Hydrocotyle; metal toxicity; phytoremediation; phenolics; flavonoids
Online: 29 June 2023 (09:35:49 CEST)
Heavy metals toxicity is a grave environmental issue in contemporary times. Phytoremediation is economic, effective and ecofriendly approach to decontaminate and remediate metal contaminated areas. Phenolic and Flavonoid content are important abiotic stress markers. The individual and combined impacts of toxiferous metals Arsenic (As), Cadmium (Cd) and (Copper) Cu were employed in recent studies to investigate their effect on Total flavonoids content (TFC) and total phenolic content (TPC) in various parts of Hydrocotyle umbellata L. to explore the role of plant in abating metal contamination. Folin- ciocalteu and AlCl 3 methods were used for investigating TPC and TFC respectively. Two-way ANOVA and CART model were employed for statistical analysis. Highest TPC was examined in decreasing order as leaf & gt; stem & gt; root in case of all the metals. Whereas highest TFC was found in all plant parts when subjected to As toxicity, and the lowest TFC was found in stem of the plant in respect to Cu toxicity. There was significant effect on TPC on plant part when subjected to Cu and As stress, but so significance was observed in plant part in case of Cd and combined metal stress. Treatment concentration had no significant effect on TPC when subjected to unique impact of all the three metals but had significant effect in case of combined metal stress. Similarly, in case of TFC no significant effect was recorded in case of plant part in all the stress types. But treatment amount has significant impact on Cd and combined metal stress. Metal type has significant effect on TPC and TFC. Whereas plant part has significant impact on TPC but non-significant values were observed on TFC in this case. This study epitomizes TPC and TFC in plants as effective and viable tool to pertain their role in phytoremediation against metal contamination. Therefore H. umbellata L. can be exerted for successful assemblage and decontamination of Cd, Cu and As in different plant parts.
ARTICLE | doi:10.20944/preprints202211.0376.v1
Subject: Chemistry And Materials Science, Medicinal Chemistry Keywords: synthesis; leishmaniasis; flavonoids; rCPB; molecular modelling.
Online: 21 November 2022 (06:29:51 CET)
Leishmaniasis is a neglected tropical disease and affects more than 350 million people worldwide. However, there are no vaccines for humans, and current treatment is hampered due to its high cost, numerous side effects, and painful administration routes. Ending its epidemics by 2030 has become a United Nations goal, and the multitarget drug strategy emerges as a promising alternative. Flavonoids are an example of multitarget compounds and organic synthesis represents a tool to obtain high yields of these molecules. In our study, we synthesized 17 flavonoid analogs using a scalable, easy-to-reproduce, and inexpensive method. All compounds demonstrated an impressive inhibition capacity against rCPB2.8, rCPB3, and rH84Y, which are highly expressed in the amastigote stage, the target form of the parasite. Compounds 3c, f12a, and f12b stood out as effective against all isoforms and intermolecular interactions were investigated through a molecular modeling study. The compounds were highly potent against the parasite and demonstrated low cytotoxic action against mammalian cells. The results were pioneering, representing an advance in the investigation of the mechanisms behind the antileishmanial action of flavonoid derivatives. Furthermore, compounds have shown to be promising leads for the design of other cysteine protease inhibitors for the treatment of leishmaniasis diseases.
ARTICLE | doi:10.20944/preprints202009.0232.v1
Subject: Chemistry And Materials Science, Applied Chemistry Keywords: limocitrol; lemon; citrus; bioeconomy; biocolorant; flavonoids
Online: 10 September 2020 (09:12:44 CEST)
A brief technical and economic insight into producing the water-soluble yellow colorant limocitrol 3-O-6”-[3-hydroxyl-3-methylglutaryl)])-β-D-glucopyranoside from waste lemon peel via simple solid-liquid extraction in aqueous ethanol or via hydrodynamic cavitation of waste lemon peel in water, shows that the biocolorant can be obtained at affordable cost. Coupled to the simplicity and sustainability of the extraction processes suggested, the high chemical and physical stability of this polymethoxylated flavanol and the health benefits of citrus flavonoids, support industrialization of this new bioeconomy production.
ARTICLE | doi:10.20944/preprints201705.0106.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: propolis; NIR spectroscopy; flavonoids; antioxidant capacity
Online: 12 May 2017 (05:53:14 CEST)
Propolis is a bee product widely used as a dietary supplement and included in sweets or baby foods due to its well-known antioxidant and nutritional properties that are directly correlated with its phenolic composition. For this reason, this study analysed the total contents of flavones and flavonols, flavanones and dihydroflavonols, and the antioxidant capacity by using the methods of ABTS and linoleic acid/β-carotene in 99 samples of propolis from Spain and Chile. A rapid method was developed for quantifying these parameters in raw propolis using near infrared (NIR) spectroscopy with an optical fibre probe of remote reflectance applied directly to the ground up sample. The models developed allow the determination of the total of flavones and flavonols (0-183 mg rutin/ g propolis), of the total of flavanones and dihydroflavonols (9-109 mg pinocembrin/ g propolis extract), and the antioxidant capacity by the ABTS method (0-3212 nmolesTrolox/ mg of propolis) and of linoleic acid/β-carotene (22-86% inhibition). The NIR spectroscopy models were applied in external validation to different samples of the calibration group, which led to the conclusion that the methods developed provide significantly identical data to the initial chemical data of reference.
ARTICLE | doi:10.20944/preprints201704.0179.v1
Subject: Medicine And Pharmacology, Pharmacology And Toxicology Keywords: medicinal plants; flavonoids; hypoglycemic; hypolipidemic; antiatherogenic
Online: 27 April 2017 (04:13:10 CEST)
Celtis iguanaea is popularly used in the treatment of diabetes mellitus. However, thorough chemical and pharmacological investigations regarding its activity are lacking. In this study, we investigated the effects of the hydroalcoholic extract from C. iguanaea (CI) on markers of cardiovascular diseases and the glucose metabolism in cholesterol-fed rats. Therefore, hypercholesterolemic rats (1% cholesterol) were orally treated with CI (150, 300, or 600 mg/kg) or simvastatin (4 mg/kg) (n = 6) once a day for 30 days along with a hypercholesterolemic diet. A control group (C) was given saline solution. CI showed significant decreases in serum levels of total cholesterol, LDL-cholesterol, HMG-CoA-reductase, IL-1, IL-6, TNF-α, and IFN-γ when compared to group C (p ˂ 0.05). Hypoglycemic effects were observed along with a decrease of the activity of sucrase (CI 600), maltase (CI 150, CI 300), and an increase in muscle glycogen levels (CI 300). Antioxidant effects were observed in plasma, and the histopathological analysis showed a significant decrease in the liver fat area for CI compared to group C (p < 0.001). Our results suggest that the biological effects of CI could be related to the presence of flavonoids that possibly exert antioxidant, enzymatic inhibitory, and insulin-mimetic effects.
ARTICLE | doi:10.20944/preprints202304.0497.v2
Subject: Biology And Life Sciences, Food Science And Technology Keywords: Antioxidants; Flavonoids; Moringa; Provitamin A; Total Phenolics
Online: 19 June 2023 (09:00:38 CEST)
This study aimed to assess the variations in the nutritional attributes of thirteen Moringa oleifera cultivars. Leaves from six-month-old plants were harvested and tested for various nutritional attributes. There were significant (p ≤ 0.05) differences in the carbohydrates, energy, some of the sugars and fibre amongst the cultivars. The levels of moisture in the cultivars ranged from 7.10% to 8.20%. Additionally, there were significant (p ≤ 0.05) differences across the cultivars in microelements studied except for zinc (Zn). These data revealed that plants from different geographical provenances differed in their adapting to varied environments. In general, under the same cultivation, management and environmental conditions, the main reasons for these differences occurred in cultivars could be associated with the genetic background of each M. oleifera germplasm. However, the study cautions on the differences of nutritional properties, as some of the cultivars have been reported not to be pharmacological potent.
ARTICLE | doi:10.20944/preprints202106.0391.v1
Subject: Biology And Life Sciences, Anatomy And Physiology Keywords: catalase; flavonoids; hydrogen peroxide; proline, soluble sugars
Online: 15 June 2021 (09:25:13 CEST)
The role of plant growth-promoting rhizobacteria (PGPR) on enhancing tolerance of plants to abiotic stresses is well reported, but the effects of RGPRs on plants under salinity stress are not widely studied in the literature. Our study aimed to investigate the effect of Halomonas sp. and Azotobacter sp. on antioxidant activity, secondary metabolites, and biochemicals changes of purple basil under salinity stress conditions. The applied salt concentrations in this study were 50, 100, and 150 mM sodium chloride (NaCl). Salinity stress had a negative effect on plant growth parameters. Moreover, a reduction in some of the osmolytes and oxidative stress markers was observed. Inoculated plants ameliorated the oxidative damage by reducing the hydrogen peroxide (H2O2) contents and by increasing osmolytes (proline, total proteins, and soluble sugars), antioxidant enzymes activities (catalase, ascorbate peroxidase) and secondary metabolites (flavonoids). Overall, among treatments, plants inoculated with Azotobacter showed a better impact on physiological attributes to alleviate the adverse effects of 150 mM NaCl salinity stress on basil growth.
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/preprints201909.0010.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: Pinus; needle; Himalayas; phenolics; flavonoids; antimicrobial; antioxidant
Online: 1 September 2019 (10:41:37 CEST)
Environmental interventions and ecological adaptations harbor millions of valued substances and metabolites in plants which can be employed and commercialized for human benefits. Present study encompasses the untapped potential of pine needles of Indo-Himalayan region for the production of different metabolites and their pharmacological significance in terms of antioxidant and antimicrobial activity. Total phenolic and flavonoid content from the needles of ten pine species was quantified using three different solvent systems. Results revealed that out of 10 different selected Pinus species, Pinus taeda showed highest concentration of total phenolics, soluble-F phenolics and flavonoids content (approx.147.02 mg/g, 141.08 mg/g and 21.91mg/g respectively) as compared to other species. On the other hand P. greggii showed highest Bound-W phenolic content (approx.3.62mg/g). Among all the selected plant species, the needles of P.echinata exhibited the highest and P.thunbergii had the lowest ratio of total flavonoids to total phenolics. Most of these compounds were found to have effective antioxidant activities as well as antimicrobial activity, as estimated by oxygen radical absorbance capacity (ORAC) and disk diffusion test respectively.
ARTICLE | doi:10.20944/preprints201609.0018.v1
Subject: Medicine And Pharmacology, Pharmacology And Toxicology Keywords: polyphenols, flavonoids, seaweeds, antioxidant activity, anticancer activity
Online: 5 September 2016 (14:23:52 CEST)
Seaweeds are considered as one of the largest biomass producers in marine environment that is rich in bioactive metabolites and a source of natural ingredients for functional foods. The potential antioxidant activity and the potential inhibition of Caco2 cell proliferation, of crude extracts of: Chlorophyta (Ulva lactuca, and Codium tomentosum), Phaeophyta (Cystoseira crinita, Cystoseira stricta, and Sargassum vulgare), and Rhodophyta (Gelidium latifolium, Hypnea musciformis, and Jania rubens) collected from western Libyan coast were evaluated in vitro. The antioxidant activity was determined by reducing power and DPPH assays while cell proliferation, morphological changes and the cell cycle arrest were assessed by MTT, inverted light microscope and flow cytometry methods respectively. The polyphenols and flavonoids rich extracts showed remarkable reducing power and antiradical properties. After exposure of Caco2 cells to; various concentrations of extracts (50, 100,150 and 200 µg/mL) especially from brown algae for 72 h, significantly reduced cell proliferation. The antiproliferative effect of algae extracts was correlated with their polyphenol and flavonoid contents. Cell cycle analysis further showed that cells were arrested in G phases along with an increment in sub-diploidal cell population (sub-G) after extract application. These results imply that seaweeds which are rich in bioactive compounds may be in anticancer drug research programs. However, further investigations are essential to reveal the molecular mechanisms of the anticancer activities of these algae.
REVIEW | doi:10.20944/preprints202305.0824.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: Flavonoids; NF-κB; cancer; neurodegenerative diseases; cardiac diseases
Online: 11 May 2023 (08:39:50 CEST)
Flavonoids are polyphenolic phytochemical compounds found in many plants, fruits, vegetables, and leaves. They have a multitude of medicinal applications due to their anti-inflammatory, anti-oxidative, anti-viral, and anti-carcinogenic properties. Furthermore, they also have neuroprotective and cardioprotective effects. Their biological properties depend on the chemical structure of flavonoids, their mechanism of action, and their bioavailability. The flavonoid’s beneficial effects have been proven for a variety of diseases. In the last few years, it is demonstrated that flavonoids’ effects are mediated by inhibiting the NF-κB (Nuclear Factor-κB) pathway. In this review, we have summarized the effects of some flavonoids on the most common diseases such as cancer, cardiovascular, and neurodegenerative human diseases. In particular, here we collected all recent studies describing plant-derived flavonoids’ protective and prevention role, by specifically focusing their action on the NF-κB signaling pathway.
REVIEW | doi:10.20944/preprints202208.0205.v1
Subject: Medicine And Pharmacology, Cardiac And Cardiovascular Systems Keywords: Cholesterol efflux; flavonoids; HDL; quercetin; reverse cholesterol transport
Online: 11 August 2022 (03:33:47 CEST)
One of the mechanisms used in the management and cure of atherosclerosis is reverse cholesterol transfer (RCT), which plays a vital role in the export of cholesterol from peripheral cells. Cholesterol efflux from macrophages in the subintima of the vessel wall is a critical part of RCT. ATP-binding cassette transporter A1 (ABCA1) and ATP-binding cassette transporter G1 (ABCG1) are involved in the transfer of cholesterol from arterial macrophages to extracellular high-density lipoprotein cholesterol (HDL). The HDL then transports esterified cholesterol to the liver for elimination. An important factor in the reverse cholesterol transport and excretion of extracellular cholesterol is HDL. Atherogenesis can be prevented by altering the processes of RCT and cholesterol efflux, and this might lead to novel treatment options for cardiovascular disease. Research of novel modifying variables for RCT and cholesterol efflux is necessary. A better understanding of RCT's molecular processes has been gained via research, allowing for the creation of new treatments that make use of RCT's potential for pharmacological improvement. The purpose of this review is to provoke discussion on the potential impact of selected flavonoids on cholesterol efflux on the progression of atherosclerosis (Fig. 1.).
ARTICLE | doi:10.20944/preprints202102.0620.v1
Subject: Chemistry And Materials Science, Food Chemistry Keywords: IntegroPectin, naringin, eriocitrin, citrus, flavonoids, pectin, circular economy
Online: 26 February 2021 (13:47:16 CET)
Following the analysis of terpenes present in new lemon and grapefruit “IntegroPectin” pectins obtained via the hydrodynamic cavitation of industrial lemon and grapefruit processing waste, the HPLC-MS analysis of the flavonoid compounds reveals the presence of eriocitrin, naringin, hesperidin and kaempferol typical of the respective citrus fruits. The pectic fibers rich in rhamnogalacturonan-I “hairy” regions act as chemical sponges adsorbing and concentrating at their outer surface highly bioactive citrus flavonoids and terpenes. These findings, together with the unique molecular structure of these new whole citrus pectins, provide preliminary insight into the broad-scope and powerful biological activity of these biomaterials. Numerous new biomedical applications beyond prevention and treatment of microbial infections and neurodegenerative disease are anticipated.
ARTICLE | doi:10.20944/preprints202101.0484.v1
Subject: Medicine And Pharmacology, Immunology And Allergy Keywords: blue honeysuckle berry; polyphenols; flavonoids; lipid accumulation; lipogenesis
Online: 25 January 2021 (11:14:20 CET)
Polyphenols have been shown to possess outstanding anti-obesity properties. In this study, the effect of blue honeysuckle berry extract (BHBE) with high polyphenol content on lipid accumulation in adipocytes and the underlying mechanism were investigated for the first time. Composition analysis demonstrated that flavonoids (mainly flavonols and anthocyanins) were the primary polyphenols in BHBE, which contributed to its biological functions. The results of Oil Red O staining combined with triglyceride (TG) content determination showed that BHBE exhibited an obvious inhibitory effect on intracellular lipid accumulation in a dose-dependent manner. BHBE also reduced the protein level of fatty acid synthase (FAS) and increased the phosphorylation level of acetyl-CoA carboxylase (ACC), indicating that lipogenesis was suppressed by BHBE treatment. Moreover, BHBE was found to significantly promote the phosphorylation of AMP-activated protein kinase (AMPK) and further reduce the expression of key transcription factors (PPARγ, C/EBPα, and SREBP-1c) that regulate lipogenesis. In addition, the expression of beige adipocyte markers (Tmem26 and Cd137) and uncoupling protein 1 (UCP1) was increased in BHBE-treated adipocytes. In summary, we consider that BHBE inhibits lipid accumulation in adipocytes by suppressing lipogenesis as well as by promoting beiging of adipocytes. These results support blue honeysuckle berry as a candidate functional food against obesity.
ARTICLE | doi:10.20944/preprints202101.0204.v1
Subject: Biology And Life Sciences, Plant Sciences Keywords: Antioxidant; Anti-inflammatory; Chitosan; Flavonoids; Phenolics; Silybum marianum
Online: 11 January 2021 (15:59:31 CET)
Silybum marianum (L.) Gaertn is a rich source of antioxidants and anti-inflammatory flavonolignans with great potential for use in pharmaceutical and cosmetic products. Its biotechnological production using in vitro culture system has been proposed. Chitosan is a well-known elicitor that strongly affects both secondary metabolites and biomass production by plants. The effect of chitosan on S. marianum cell suspension is not known yet. In the present study, suspension cultures of S marianum were exploited for their in vitro potency to produce bioactive flavonolignans in the presence of chitosan. Established cell suspension culture was maintained on the same hormonal media supplemented with 0.5 mg/L BAP (6-benzylaminopurine) and 1.0 mg/L NAA (α-naphthalene acetic acid) under photoperiod 16/8 h (light/dark) and exposed to various treatments of chitosan (ranging from 0.5 to 50.0 mg/L). The highest biomass production was observed for cell suspension treated with 5.0 mg/L chitosan, resulting in 123.3 g/L fresh weight (FW) and 17.7 g/L dry weight (DW) productions. Chitosan treatment resulted in an overall increase in the accumulation of flavonoids, phenolic compounds and silymarin. High accumulation levels of silybin B, silydianin and silybin A were recorded by HPLC analysis. The corresponding extracts displayed interesting antioxidant and anti-inflammatory capacities. In particular, high ABTS antioxidant activity (741.5 μM Trolox C equivalent antioxidant capacity) was recorded in extracts obtained in presence of 0.5 mg/L of chitosan. On the opposite, highest inhibitions of cyclooxygenase 2 (COX-2, 30.5 %), secretory phospholipase A2 (sPLA2, 33.9 %) and 15-lipoxygenase (15-LOX-2, 31.6 %) enzymes involved in inflammation process were measured in extracts obtained in presence of 5.0 mg/L of chitosan. Taken together, these results highlight the high potential of the chitosan elicitation of the S. marianum cell suspension for enhanced production of antioxidant and anti-inflammatory silymarin-rich extracts.
ARTICLE | doi:10.20944/preprints202003.0386.v1
Subject: Biology And Life Sciences, Virology Keywords: hesperidin; COVID-19; pectin; flavonoids; hydrodynamic cavitation; IntegroPectin
Online: 26 March 2020 (13:59:28 CET)
Computational studies suggest that hesperidin, a flavonoid abundant in citrus peel, binding the three main cellular receptors of SARS-CoV-2 virus can act in the prophylaxis and treatment of COVID-19. Herein we urge the uptake of hydrodynamic cavitation industrial-scale reactors based on the low cost, reliable Venturi tube for the extraction of citrus pectin rich in hesperidin (and in other bioflavonoids including naringing) by very fast processing of waste orange peel or waste lemon peel in water only. A device able to process up to 500 kg of waste peels per session, similar to the one lately deployed in Italy for hydrodynamic cavitation-assisted brewing, is capable to provide 36,000 doses of 1000 mg hesperidin per day.
ARTICLE | doi:10.20944/preprints202003.0333.v1
Subject: Medicine And Pharmacology, Pathology And Pathobiology Keywords: COVID-19; SARS-CoV-2; molecular docking; flavonoids
Online: 23 March 2020 (04:30:47 CET)
COVID-19, a rapidly spreading new strain of coronavirus, has affected more than 150 countries and received worldwide attention. The lack of efficacious drugs or vaccines against SARS-CoV-2 has further worsened the situation. Thus, there is an urgent need to boost up research for the development of effective therapeutics and affordable diagnostic against COVID-19. The crystallized form of SARS-CoV-2 main protease (Mpro) was demonstrated by a Chinese researcher Liu et al. (2020) which is a novel therapeutic drug target. This study was conducted to evaluate the efficacy of medicinal plant-based bioactive compounds against COVID-19 Mpro by molecular docking study. Molecular docking investigations were performed by using Molegro Virtual Docker 7 to analyze the inhibition probability of these compounds against COVID-19. COVID-19 Mpro was docked with 80 flavonoid compounds and the binding energies were obtained from the docking of (PDB ID: 6LU7: Resolution 2.16 Å) with the native ligand. According to obtained results, hesperidin, rutin, diosmin, apiin, diacetylcurcumin, (E)-1-(2-Hydroxy-4-methoxyphenyl)-3-[3-[(E)-3-(2-hydroxy-4- methoxyphenyl)-3-oxoprop-1-enyl]phenyl]prop-2-en-1-one, and beta,beta'-(4-Methoxy-1,3- phenylene)bis(2'-hydroxy-4',6'-dimethoxyacrylophenone have been found as more effective on COVID-19 than nelfinavir. So, this study will pave a way for doing advanced experimental research to evaluate the real medicinal potential of these compounds to cure COVID-19.
ARTICLE | doi:10.20944/preprints201912.0273.v1
Subject: Biology And Life Sciences, Agricultural Science And Agronomy Keywords: Capsicum annuum; flavonoids; fluorescence monitoring; bio-waste utilization
Online: 20 December 2019 (11:05:22 CET)
The green biomass of horticultural plants contains valuable secondary metabolites (SM) which can potentially be extracted and sold. When exposed to stress, plants accumulate higher amounts of these SMs, making the extraction and commercialization even more attractive. We evaluated the potential for accumulating of the flavones cynaroside and graveobioside A in leaves of two bell pepper cultivars (Mavras and Stayer) when exposed to salt stress (100 mM NaCl), UVA/B excitation (UVA 4-5 W/m²; UVB 10-14 W/m² for 3 hours per day) or a combination of both stressors. HPLC analyses proved the enhanced accumulation of both metabolites under stress conditions. Cynaroside accumulation is effectively triggered by high-UV stress, whereas graveobioside A contents increase under salt stress. Highest contents were observed in plants exposed to combined stress. Effects of stress on overall plant performance differed significantly between treatments, with least negative impact on aboveground biomass found for high-UV stressed plants. The usage of two non-destructive instruments (Dualex and Multiplex) allowed us to gain insights in ontogenetical effects at the leaf level and temporal development of SM contents over time. Indices provided by those devices correlate fairly with amounts detected via HPLC (Cynaroside: R2 = 0.46 – 0.66; Graveobioside A: R2 = 0.51 – 0.71). The concentrations of both metabolites tend to decrease at leaf level during the ontogenetical development even under stress conditions. High-UV stress is a promising tool for enriching plant leaves with valuable SM without major effects on plant biomass. All data is available online .
ARTICLE | doi:10.20944/preprints201906.0103.v1
Subject: Biology And Life Sciences, Plant Sciences Keywords: chalcone synthase; drought stress; flavonoids; transgenic tobacco; overexpression
Online: 12 June 2019 (05:39:29 CEST)
Flavonoids are major secondary metabolites in plants, which play important roles in maintaining the cellular redox balance in cells. Chalcone synthase (CHS) is the key enzyme in the flavonoids biosynthesis pathway, and has been proved to monitor the changes to drought stress tolerance. In this work, we overexpressed a CHS gene in tobacco (Nicotiana tabacum). The transgenic tobacco plants were more tolerant than the control plants to drought stress. The transcription levels of the key genes involved in the flavonoids pathway and the contents of seven flavonoids were also significantly raised in the transgenic tobacco plants. In addition, overexpression of the CHS gene lead to a lower concentration of the oxidative stress product malondialdehyde. Overall, the NtCHS gene studied in this work was considered as a candidate gene for genetic engineering to enhance drought tolerance of plants and improve response to oxidative stress.
ARTICLE | doi:10.20944/preprints201807.0399.v1
Subject: Biology And Life Sciences, Food Science And Technology Keywords: flavonoids; dark chocolate; genotoxicity; lipid metabolism; glucose metabolism
Online: 22 July 2018 (11:05:27 CEST)
In recent years, Atherosclerotic Cardiovascular Disease (ACVD), Obesity and Diabetes, have increase exponentially worldwide. In the present work, we evaluate the genoprotective effect of consuming a flavonoids-rich chocolate and the improvement in the biochemical parameters related to the prevention and treatment of cardiovascular risk and metabolic syndrome in young Mexican adults. A randomized, placebo-controlled, double-blind study was undertaken in the Autonomous University of Baja California. The treatments were a daily intake of 2 grams of dark chocolate containing 70% cooca or milk chocolate. Total phenolic compounds and flavonoids were evaluated in both chocolates. Anthropometrical and Biochemical parameters were measured in the 84 participants before and after the study. Buccal epithelial genotoxicity was also evaluated from the beginning to the end of the experiment in the participants. Result suggested that flavonoids of cocoa intake have protective effects against DNA damage, and Biochemical parameters (total cholesterol, triglycerides, and LDL-cholesterol level in blood) and anthropometrical parameters (waist circumference) were also improved after six months of daily intake of 2 grams of dark chocolate with a 70% of cocoa.
REVIEW | doi:10.20944/preprints202308.1064.v1
Subject: Chemistry And Materials Science, Medicinal Chemistry Keywords: Cancer; phytomolecules; fused oxygen-based heterocycles; anticancer; flavonoids; coumarins
Online: 16 August 2023 (09:57:17 CEST)
Oxygen based heterocyclic moieties hold an ample range of therapeutic activities. Heterocyclic molecules are nominated as vital components of an extensive array of structural motifs with both biological and pharmaceutical significance. The oxygen-based scaffolds act as anticancer candidates and are also present in numerous phytomolecules viz; irinotecan, camptothecin, topotecan, taxol, taxotere, podophylotoxin, etoposide, daunorubicin and teniposide. The architectural design of numerous structural motifs for amelioration of cancer has become progressively amplified in recent past years. Until now presently there is no strategic treatment which is so capable that can cure cancer from its roots. Henceforth, it is very indispensible to design novel anticancer structural motifs with least side effects. The oxygen containing heterocyclic scaffolds includes flavonoids, pyrans, xanthones and coumarins are of utmost importance in medical chemistry for the mitigation of cancer. This assemblage offers several recent developments as anticancer oxygen containing heterocyclic molecules all-round the globe and attracted the structural motifs of auspicious molecules, along with their mechanistic insights, IC50 values, structure–activity relationships, and molecular docking studies. The encouraging properties discovered by these oxygen-based scaffolds unconditionally engaging them at frontline in invention of potential drug candidates. Consequently, these probably will be of amazing attention to scientists working on the design and synthesis of antitumor candidates.
ARTICLE | doi:10.20944/preprints202209.0440.v1
Subject: Medicine And Pharmacology, Medicine And Pharmacology Keywords: infectious diseases; chikungunya; antiviral; flavonoids; fisetin; toll-like receptors
Online: 28 September 2022 (12:15:36 CEST)
In the chronic phase of chikungunya virus (CHIKV) infection, excessive inflammation manifests as incapacitating joint pain and prolonged arthritis. Arthritis resulted from a large influx of infiltrating immune cells driven by pro-inflammatory cytokines and chemokines originating from the toll-like receptor (TLR)-mediated innate antiviral response. This study investigated fisetin's ability to modulate TLR-mediated antiviral responses against CHIKV in Huh7 cells. The CHIKV inhibitory potential of fisetin was assessed by plaque-forming unit assay, virus yield reduction assay, and bright-field microscopy (cytopathic effect, immunofluorescence). Fisetin’s modulatory potential on TLR-mediated antiviral response was evaluated by immunofluorescence assay (expression of TLR proteins), qRT-PCR (mRNA level of antiviral genes), human cytokine array, and immunoblotting of key transcription factors. The present study showed fisetin induced the expression of the antiviral genes at an early time-point by promoting the phosphorylation of IRF3 and IRF7. Fisetin reduced excessive inflammatory cytokine responses in CHIKV-infected Huh7 cells by impeding the over-phosphorylation of NF-κB. Fisetin also reduced CHIKV-induced cytopathic effects in CHIKV-infected Huh7 cells. Altogether, our study suggests that fisetin modulates TLR-mediated antiviral responses by affecting the CHIKV-induced inflammatory responses.
ARTICLE | doi:10.20944/preprints201807.0384.v1
Subject: Medicine And Pharmacology, Urology And Nephrology Keywords: Flavonoids, nitric oxide, heart, kidney, sodium balance, phenylephrine, acetylcholine
Online: 20 July 2018 (12:57:00 CEST)
We have evaluated the antihypertensive effect of several flavonoid extracts in the spontaneous hypertensive rat model (SHR). Treatments were carried out for 6 and 12 weeks in two groups of SHR rats which received Apigenin, Lemon Extract, Grapefruit + Bitter Orange (GBO) extracts and Cocoa extract. Captopril was used as a positive control in the SHR group treated for 6 weeks (SHR6) and Diosmin was used as the industry reference in the SHR group treated for 12 weeks (SHR12). Captopril and GBO extracts significantly reduced the elevated blood pressure of the SHR6 animals, but none of the extracts was effective in the SHR12 group. Apigenin, LE, GBO and captopril also ameliorated nitric oxide-dependent and independent aortic vascular relaxation and elevated plasma and urinary excretion of nitrites, only in the SHR6 group. Kidney and urinary TBARS were also significantly reduced by GBO in the SHR6 rats. Apigenin also improved vascular relaxation in the SHR12 group and all the flavonoids studied reduced urinary TBARS excretion and proteinuria. Vascular abnormalities such as lumen/wall ratio in coronary arteries and thoracic aorta were moderately improved by these treatments in the SHR6 group. In conclusion, the flavonoids included in this study, especially apigenin, LE and GBO improved vascular vasodilatory function of young adult SHRs but only the GBO-treated rats benefited from a reduction in BP. These extracts may be used as functional food ingredients with a moderate therapeutic benefit, especially in the early phases of arterial hypertension.
REVIEW | doi:10.20944/preprints201805.0462.v1
Subject: Medicine And Pharmacology, Dietetics And Nutrition Keywords: sphingolipids; ceramide; flavonoids; resveratrol; genistein; curcumin, nutrients; nutraceuticals; chemotherapeutics
Online: 31 May 2018 (08:26:07 CEST)
The latest scientific literature outlines a resilient interconnection between cancer modulation and dietary polyphenols by sphingolipid-mediated mechanisms, usually correlated with a modification of their metabolism. We aim to extensively survey this relation to show how it could be advantageous in cancer treatment or prevention by nutrients. Polyphenols, chemically characterized by polyhydroxylated phenolic structure, are well known for their pervasive pharmacological properties: anti-inflammatory, antibiotic, antiseptic, antitumor, antiallergic, cardioprotective and others. Pervasive is also their distribution in food products especially in plant foods as vegetables, cereals, legumes, fruits, nuts and beverages as wine, cider, beer, tea, cocoa. Recently, sphingolipids have been correlated with cancer by a dysregulation of their rheostat emerging as mediator of cell proliferation in cancer and modulator of chemotherapeutics.
ARTICLE | doi:10.20944/preprints201803.0060.v1
Subject: Medicine And Pharmacology, Pharmacology And Toxicology Keywords: flavonoids; nitric oxide; heart; kidney; sodium balance; phenylephrine; acetylcholine
Online: 8 March 2018 (03:31:29 CET)
1) Background: we have evaluated the antihypertensive effect of several flavonoid extracts in a rat model of arterial hypertension caused by chronic administration (6 weeks) of the nitric oxide synthesis inhibitor, L-NAME. 2) Methods: Sprague Dawley rats received L-NAME alone or L-NAME plus flavonoid-rich vegetal extracts (Lemon, Grapefruit + Bitter Orange, and Cocoa) or purified flavonoids (Apigenin and Diosmin) for 6 weeks. 3) Results: L-NAME treatment resulted in a marked elevation of blood pressure, and treatment with Apigenin, Lemon Extract, and Grapefruit + Bitter Orange extracts significantly reduced the elevated blood pressure of these animals. Apigenin and some of these flavonoids also ameliorated nitric oxide-dependent and independent aortic vasodilation and elevated nitrite urinary excretion. End-organ abnormalities such as cardiac infarcts, hyaline arteriopathy and fibrinoid necrosis in coronary arteries and aorta were improved by these treatments, reducing the end-organ vascular damage. 4) Conclusions: the flavonoids included in this study, specially apigenin, may be used as functional food ingredients with potential therapeutic benefit in arterial hypertension.
ARTICLE | doi:10.20944/preprints202311.0097.v1
Subject: Chemistry And Materials Science, Medicinal Chemistry Keywords: Leishmania; Asteraceae; DHFR-TS; Lignans; Flavonoids; Natural products; Machine learning.
Online: 1 November 2023 (12:46:39 CET)
The critical enzyme Dihydrofolate Reductase-Thymidylate Synthase in Leishmania major (LmDHFR-TS) serves a dual-purpose role and is essential for DNA synthesis, a cornerstone of the parasite's reproductive processes. Consequently, the development of inhibitors against LmDHFR-TS is crucial for the creation of novel anti-Leishmania chemotherapies. In this study, we employed an in-house database containing 314 secondary metabolites derived from cinnamic acid that occurred in the Asteraceae family. We conducted a combined ligand/structure-based virtual screening to identify potential inhibitors against LmDHFR-TS. By consensus analysis of both approaches, we identified three compounds, i.e., lithospermic acid (237), diarctigenin (306), and isolappaol A (308), that exhibited a high probability of being inhibitors according to both approaches and were consequently classified as promising hits. Subsequently, we expanded the binding mode examination of these compounds within the active site of the test enzyme through molecular dynamics simulations, revealing a high degree of structural stability and minimal fluctuations in its tertiary structure. The in-silico predictions were then validated through in-vitro assays to examine the inhibitory capacity of the top-ranked naturally-occurring compounds against LmDHFR-TS recombinant protein. The test compounds effectively inhibited the enzyme with IC50 values ranging from 6.1 to 10.1 μM. In contrast, other common cinnamic acid derivatives (i.e., flavonoid glycosides) from the Asteraceae family, such as hesperidin, isovitexin 4′-O-glucoside, and rutin, exhibited low activity against this target. The selective index (SI) for all tested compounds was determined using HsDHFR, with moderate inhibitory effect. Among these hits, lignans 306 and 308 demonstrated the highest selectivity, displaying superior SI values compared to methotrexate, the reference inhibitor of DHFR-TS. Therefore, continued research into the anti-leishmanial potential of these C6C3-hybrid butyrolactone lignans may offer a brighter outlook for combating this neglected tropical disease.
ARTICLE | doi:10.20944/preprints202310.0369.v1
Subject: Biology And Life Sciences, Plant Sciences Keywords: Field; Parkinson’s disease; flavonoids; isoorientin; yield; rutin; Vicia faba L.
Online: 9 October 2023 (11:58:52 CEST)
The broad bean plant contains L-DOPA, a compound that is essential for patients with Parkin-son’s disease. However, little has been reported on other broad bean compounds that have bene-ficial effects on health. The objective was to evaluate plants of four Mexican broad bean varieties to determine the content and yield of total phenolic compounds (TPC), total flavonoids (TF), and L-DOPA, as well as to analyze the flavonoid profile and antioxidant (AA) and anti-inflammatory (AANTI) activity in vitro. Broad bean seeds were sown in the field and plants were harvested 20 days after emergence. The analyses were performed with visible UV spectrophotometry and HPLC. The variety José María produced the highest yield of TPC (9.30 g m-2), TF (8.08 g m-2) and L-DOPA (5.64 g m-2) per unit of area. The highest yields per plant were obtained with the Rojita variety: TPC (0.25 g plant-1), TF (0.21 g plant-1) and L-DOPA (0.17 g plant-1). This variety also had the highest antioxidant (CI50= 87.68 µg mL-¹) and anti-inflammatory (CI50= 74.40 mg mL-1) activi-ty, which was attributed to the L-DOPA compounds and to rutin and isoorientins, respectively. The flavonoid profile revealed the presence of rutin and isoorientins, which had not been previ-ously detected in the broad bean plant.
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/preprints202105.0171.v1
Subject: Medicine And Pharmacology, Immunology And Allergy Keywords: C. dichotoma; Flavonoids; Antidiabetic; alpha-glucosidase, alpha-amylase, Docking; ADMET
Online: 10 May 2021 (11:02:24 CEST)
Cordia dichotoma Forst. (F. Boraginaceae) has been traditionally used for the management of a variety of human ailments. In our earlier work, the antidiabetic activity of methanolic bark extract of C. dichotoma (MECD) has been reported. In this paper, two flavonoid molecules were isolated (by column chromatography) and identified (by IR, NMR and Mass spectroscopy/spectrometry) from the MECD with an aim to investigate their antidiabetic effectiveness. Molecular docking and ADMET studies were carried out using AutoDock Vina software and Swiss ADME online tool, respectively. The isolated flavonoids were identified as 3,5,7,3’,4’-tetrahydroxy-4-methoxyflavanone-3-O-L-rhamnopyranoside and 5,7,3’-trihydroxy-4-methoxyflavanone-7-O-L-rhamnopyranoside (quercitrin). Docking and ADMET studies revealed the promising binding affinity of flavonoid molecules for human lysosomal alpha-glucosidase and human pancreatic alpha-amylase with acceptable ADMET properties. Based on computational studies, our study reports the antidiabetic potential of the isolated flavonoids with predictive pharmacokinetics profile.
ARTICLE | doi:10.20944/preprints202103.0652.v1
Subject: Chemistry And Materials Science, Analytical Chemistry Keywords: chitosan coating; edible coating; guava fruit; shelf-life; HPLC; flavonoids
Online: 26 March 2021 (10:12:24 CET)
Guava is a vital fruit worldwide, especially in Pakistan, and due to its nutritional value famous in each age group. Due to a very short shelf life, the marketing and export of this fruit faced severe constraints. Therefore, in the current study, edible coating of chitosan (0, 0.5, 1.0, 1.5, and 2.0%) was evaluated on postharvest shelf life when guava fruits were stored (room temperature and 4 °C temperatures) for 12 days. The chitosan treated coating fruits have shown reduced total sugars and malondialdehyde levels compared to untreated control samples. However, a significant difference (p ≤ 0.05) in total sugar and malondialdehyde levels exists between samples stored in m compared to refrigerated temperature (4 °C). The chitosan-coated samples have shown a greater amount of vitamin C, quercetin, rutin, and total phenolic contents than control samples. However, these nutritional parameters' levels were significantly different (p ≤ 0.05) in samples stored at room than samples stored at refrigerated temperature. However, the levels of crude fiber, potassium, and sodium were found statistically nonsignificant (p ≥0.05) in control versus chitosan treated coating treatments. The findings have documented that the coatings of 1.5 and 2.0% were most effective for extension in shelf life and maintaining the nutritional attributes of guava fruit.
REVIEW | doi:10.20944/preprints202010.0551.v2
Subject: Medicine And Pharmacology, Pharmacology And Toxicology Keywords: cannabinoids; Δ9-tetrahydrocannabinol; cannabidiol; non-cannabinoids; flavonoids; terpenes; secondary metabolites
Online: 26 November 2020 (11:13:18 CET)
The Cannabis plant (Cannabis sativa L.) produces an estimated 545 chemical compounds of different biogenetic classes. In addition to economic value, many of these phytochemicals have medicinal and physiological activity. The plant is most popularly known for its two most prominent and most studied secondary metabolites— Δ9-Tetrahydrocannabinol (Δ9-THC) and Cannabidiol (CBD). Both Δ9-THC and CBD have a wide therapeutic window across many ailments and form part of a class of secondary metabolites called cannabinoids—of which approximately over 104 exist. This review will focus on non-cannabinoid metabolites of Cannabis sativa that also have therapeutic potential, some of which share medicinal properties similar to those of cannabinoids. The most notable of these non-cannabinoid phytochemicals are flavonoids and terpenes. We will also discuss future directions in cannabis research and development of cannabis-based pharmaceuticals. Caflanone, a flavonoid molecule with selective activity against the human viruses including the coronavirus SARS-COV2, and certain cancers, is one of the most promising non-cannabinoid molecules that is being advanced into clinical trials. As validated by thousands of years of the use of cannabis for medicinal purposes, vast anecdotal evidence abounds on the medicinal benefits of the plant. These benefits are attributed to the many phytochemicals in this plant, including non-cannabinoids. The most promising non-cannabinoids with potential to alleviate global disease burdens are discussed.
REVIEW | doi:10.20944/preprints202008.0699.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: heterologous production; shikimic acid pathway; phenolic acids; flavonoids; anthocyanins; stilbenes
Online: 31 August 2020 (05:02:19 CEST)
Secondary phenolic metabolites are defined as valuable natural products synthesized by different organisms that are not essential for growth and development. These compounds play an essential role in plant defense mechanisms, and an important role in the pharmaceutical, cosmetics, food, and agricultural industries. Despite the vast chemical diversity of natural compounds, their content in plants is very low, in consequence, it eliminates the possibility of the production of these interesting secondary metabolites from plants. Therefore, microorganisms are widely used as cell factories by industrial biotechnology to the production of different non-native compounds. Among microorganisms commonly used in biotechnological applications, yeasts are prominent host for the diverse secondary metabolite biosynthetic pathways. Saccharomyces cerevisiae is often regarded as the better host organism for the heterologous production of phenolics compounds, especially if the expression of different plant genes is necessary.
ARTICLE | doi:10.3390/sci2020031
Subject: Biology And Life Sciences, Agricultural Science And Agronomy Keywords: Khechechuri pear; Adjara region; phenolic compounds; catechins; flavonoids; antioxidant activity
Online: 9 May 2020 (00:00:00 CEST)
An endemic pear species spreads in one region of western Georgia, Adjara, called Khechechuri. Pears are dietary source of bioactive components such as polyphenols and triterpenic acid. In addition to its gastronomic value, the aim of the article was to examine and compare phenolic compounds, flavonoids, catechins, phenolic acids, and antioxidant activities in five species of Khechechuri collected from various regions in Adjara region: Adjaristskali, Merisi, Dandalo, Shuakhevi, and Khulo. Five fruit parts, the skin, edible pulp, the whole pear (skin + pulp), juice and the pomace were analyzed and the results were compared. Our study revealed that the amount of total phenolic content found in the skin of West Georgian pear types was as much as 4650 mg/kg. Also, the pear pomace showed significant amount of total phenolic content in all species of Khechechuri. In addition, in all species of Khechechuri pears, flavonoids were found, except in the fruit juice.
ARTICLE | doi:10.20944/preprints201807.0251.v1
Subject: Chemistry And Materials Science, Medicinal Chemistry Keywords: docking; epigenetics; epi-informatics; molecular interactions; molecular dynamics; natural products; flavonoids
Online: 14 July 2018 (17:45:16 CEST)
Flavonoids are widely recognized as natural polydrugs, given their anti-inflammatory, antioxidant, sedative and antineoplastic activities. Recently, different studies have shown that flavonoid have the potential to inhibit BET bromodomains. Previous reports suggest that flavonoids are putative inhibitors of the ZA channel due to their orientation and interactions with P86, V87, L92, L94 and N140. Herein, a comprehensive characterization of the binding mode of the biflavonoid amentoflavone and fisetin is discussed. To this end, both compounds were docked with BRD4 using four docking programs. Results were post-processed with protein-ligand interaction fingerprints. To gain further insights into the binding mode of the two natural products, docking results were further analyzed with molecular dynamics. Results showed that amentoflavone makes numerous contacts in the ZA channel, as previously described for flavonoids and kinase inhibitors. It was also found that amentoflavone can potentially make contacts with non-canonical residues for BET inhibition. Most of these contacts were not observed with fisetin. Based on these results, amentoflavone was tested for BRD4 inhibition, showing activity in the micromolar range. This work may serve as basis for scaffold optimization and further characterization of flavonoids as BET inhibitors.
ARTICLE | doi:10.20944/preprints201711.0184.v2
Subject: Chemistry And Materials Science, Food Chemistry Keywords: Cistus incanus; Strandja; antioxidants; polyphenols; flavonoids; seasonality; buds; hard-coated seeds
Online: 2 January 2018 (11:21:12 CET)
The purpose of the present study is survey of extraction conditions and exploring antioxidant potential of the non-traditional for the Bulgarian ethno-medicine wild herb Cistus incanus widespread in Strandja Mountain. The influence of the extraction time (0–500 min) and solvent composition (0–50% ethanol in water) on the polyphenols, flavonoids yields and on antioxidant capacity of the extracts of leaves, stalks (wood parts) and buds mixture were studied. The antioxidant capacity (AOC) was evaluated by use of scavenging assays of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals. Total polyphenol and flavonoid contents were quantified using UV–vis spectrometry. Optimal yield of desired components has been obtained with 30% ethanol in water solvent at 390th min extraction time. In addition, the influence of the seasonality (winter and summer Cistus incanus), and of the different areal parts - hard-coated seeds; buds, and mixture of leaves and stalks of the wild plant on the presence of polyphenols, flavonoids and AOC were investigated. Present work revealed the high values of the polyphenols, flavonoids, the high AOC not only in the summer leaves, but also found in the winter leaves, hard-coated seeds, buds and stalks. Based on the obtained results the Cistus incanus from Strandja mountain could be a new excellent source of natural antioxidants in food and pharmaceutical industries.
ARTICLE | doi:10.20944/preprints202308.2113.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: herbs; spices; flavonoids; antioxidants; diabetes; volatile compounds; drug discovery; phytochemicals; human health
Online: 31 August 2023 (10:12:18 CEST)
Culinary herbs and spices are widely used in daily diets. Pakistan flora is enriched with phytochemicals due to a diverse range of land. Phytochemicals, including volatile and non-volatile compounds, have captured much interest due to their numerous health advantages and significance in daily diet. The present study aimed to conduct in-depth metabolomic profiling of Pakistani-grown fenugreek leaves (Trigonella foenum-graecum), fennel seeds (Foeniculum vulgare), mint leaves (Mentha royleana), coriander seeds (Coriandrum sativum) and basil leaves (Ocimum basilicum) by using liquid chromatography–mass spectrometry (LC-MS/MS) and gas chromatography–mass spectrometry (GC-MS). The first study was conducted to optimize extraction using different solvents (methanol, ethanol, chloroform, acetone, and water). Total phenolic content (TPC), total flavonoid content (TFC), and total condensed tannins (TCT) were quantified along with the antioxidant and anti-diabetic activities. The highest TPC (125.42 ± 10.89 mg GAE/g) and the highest antioxidant and anti-diabetic potential were quantified in mint. Seventy-one phytochemical metabolites were identified using LC-MS/MS, while forty-nine volatile constituents were identified using the GC-MS. A positive correlation was identified between phenolic contents and their biological activities. Furthermore, molecular docking helped to find drug molecules with more excellent anti-diabetic activity based on their binding affinities. This study suggests that selected medicinal herbs from Pakistan have significant nutraceutical and phytopharmaceutical potential. This study could further help in drug discovery.
REVIEW | doi:10.20944/preprints202307.0045.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: ERMs; flavonoids; luteolin; mast cells; mediators; moesin; phosphorylation; secretion; SNAREs; SNAPs; tryptase
Online: 3 July 2023 (09:55:52 CEST)
Mast cells play a critical role in allergies and inflammation via secretion of numerous vasoactive, pro-inflammatory and neuro-sensitizing mediators. Secretion may utilize different modes that involve the cytoskeleton, but our understanding of the molecular mechanisms regulating secretion is still not well understood. We previously showed that the ability of the so called mast cell “stabilizer” disodium cromoglycate (cromolyn) to inhibit secretion from rat mast cells closely paralleled the phosphorylation of a 78 kDa protein, and subsequently showed this protein to be moesin, a member of the Ezrin/Radixin/Moesin (ERM) family of proteins, which are involved in linking cell surface-initiated signaling to the actin cytoskeleton. Unlike phosphorylation on the C-terminus Thr558 associated with activation of ERMs, including secretion from macrophages and platelets, we showed that phosphorylation of moesin during inhibition of secretion was on the N-terminal Ser56/74 and Thr66 residues. This phosphorylation pattern could lock moesin in its inactive state and remain inaccessible to bind to the Soluble NSF attachment protein receptors (SNAREs) and synaptosomal associated proteins (SNAPs). Using Confocal microscopic imaging, we showed moesin to colocalize with actin and cluster around secretory granules during inhibition of secretion, In conclusion, the phosphorylation pattern and localization of moesin may be important in the regulation of mast cell secretion and could be targeted for the development of effective inhibitors of secretion from mast cells.
ARTICLE | doi:10.20944/preprints202208.0342.v1
Subject: Medicine And Pharmacology, Cardiac And Cardiovascular Systems Keywords: Citrus flavonoids; naringin; naringenin; pectin; byproducts; anti-ischemic myocardial protection; hydrodynamic cavitation
Online: 18 August 2022 (10:54:33 CEST)
Citrus flavonoids are well-known for beneficial effects at the cardiovascular and cardio-metabolic level, but often the encouraging in vitro results are not confirmed by in vivo approaches; also clinical trials are inconsistent. The limited bioavailability of them can be, at least in part, the reason of these discrepancies. Therefore many efforts were performed towards the improvement of their bioavailability. Hydrodynamic cavitation methods were successfully applied to the extraction of byproducts of the Citrus fruits industry, showing high process yields and affording stable phytocomplexes, known as IntegroPectin, endowed with great amounts of bioactive compounds and high water solubility. Cardioprotective effects of grapefruit IntegroPectin were evaluated by an ex vivo ischemia/reperfusion protocol. A further pharmacological characterization was carried out to assess the involvement of mitochondrial potassium channels. Grapefruit IntegroPectin, where naringin represented 98% of flavonoids, showed anti-ischemic cardioprotective activity, better than pure naringenin (the bioactive aglycone of naringin). On cardiac isolated mitochondria, this extract confirmed that naringenin/naringin were involved in the activation of mitochondrial potassium channels. The hydrodynamic cavitation-based extraction confirmed a valuable opportunity for the exploitation of Citrus fruits waste, with the end product presenting high levels of Citrus flavonoids and an improved bioaccessibility that enhances its nutraceutical and economic value.
REVIEW | doi:10.20944/preprints202103.0154.v1
Subject: Biology And Life Sciences, Anatomy And Physiology Keywords: β-glucans; polysaccharides; flavonoids; anthocyanins; antioxidants; biological role of pigments; gene families
Online: 4 March 2021 (11:19:12 CET)
Cereal crops, such as oats and barley, possess a number of valuable properties that meet the requirements for functional diet components. This review summarized the available information about bioactive compounds of oat and barley grain. The results of studying the structure and physicochemical properties of the cell wall polysaccharides of barley and oat are presented. The main components of the flavonoids formation pathway are shown and data, concerning anthocyanins biosynthesis in various barley tissues, are discussed. Moreover, we analyzed the available information about structural and regulatory genes of anthocyanin biosynthesis in Hordeum vulgare L. genome, including β-glucan biosynthesis genes in Avena sativa L species. However, there is not enough knowledge about genes responsible for biosynthesis of β-glucans and corresponding enzymes and plant polyphenols. The review also covers contemporary studies about collections of oat and barley genetic resources held by VIR. This review intended to provide information on the processes of biosynthesis of biologically active compounds in cereals that will promote further researches devoted to transcription factors controlling expression of structural genes and their role in other physiological processes in higher plants. Found achievements will allow breeders to create new highly productive varieties with the desirable properties.
REVIEW | doi:10.20944/preprints202101.0384.v1
Subject: Medicine And Pharmacology, Immunology And Allergy Keywords: flavonoids; cellular stress response; neurodegenerative disorders; ER stress proteotoxicity; oxidative stress; neuroinflammation
Online: 19 January 2021 (14:02:03 CET)
Neurodegenerative disorders such as Parkinson’s disease (PD), Alzheimer’s disease (AD), Amyloidal lateral sclerosis (ALS), and Huntington disease (HD) are the most concerned disorders due to the lack of effective therapeutics and dramatic rise in affected cases. Although these disorders have diverse clinical manifestations, yet they all share a common cellular stress response. These cellular stress responses including neuroinflammation, oxidative stress, proteotoxicity, and ER-stress, which combats with stress conditions, but the overwhelming cellular stress response induces cell damage. Small molecules such as flavonoids could reduce cellular stress and have gained much attention in recent years. Evidence has shown the potential use of flavonoids in several ways such as antioxidants, anti-inflammatory, and anti-apoptotic, yet their mechanism is still elusive. This review provides an insight into the mechanistic ways of flavonoids against cellular stress response that prevent the pathogenesis of neurodegenerative disorders.
ARTICLE | doi:10.20944/preprints201903.0007.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: Silybum marianum L.; Light regimes; Melatonin; Antioxidant; Phenolics; Flavonoids; Silymarin; Anti-inflammatory
Online: 1 March 2019 (12:20:03 CET)
Silybum marianum L. is a well-known medicinal herb, primarily used in liver protection. Light strongly affects several physiological processes along with secondary metabolites biosynthesis in plants. Herein, S. marianum was exploited for in vitro potential under different light regimes in the presence of melatonin. The optimum callogenic response occurred in combination of 1.0 mg/L α-naphthalene acetic acid and 0.5 mg/L 6-Benzylaminopurine under photoperiod. Continuous light associated with melatonin treatment increased total flavonoid content (TFC), total phenolic content (TPC) and antioxidant potential, followed by photoperiod and dark treatments. The increased level of melatonin has a synergistic effect on biomass accumulation under continuous light and photoperiod, while adverse effect was observed under dark condition. More detailed phytochemical analysis showed maximum total silymarin content (11.92 mg/g DW) when placed under continuous light + 1.0 mg/L melatonin. Individually, the level of silybins (A and B), silydianin, isolsilychristin and silychristin was found highest under continuous light. Anti-inflammatory activities were also studied and highest percent inhibition was recorded against 15-LOX for cultures cultivated under continuous light (42.33%). The current study helps to better understand the influence of melatonin and different light regimes on silymarin production as well as antioxidant and anti-inflammatory activities in S. marianum callus extracts.
ARTICLE | doi:10.20944/preprints201712.0082.v1
Subject: Chemistry And Materials Science, Analytical Chemistry Keywords: natural dyes; flavonoids; flavone glycosides; anthraquinones; extraction procedure; liquid chromatography mass spectrometry
Online: 13 December 2017 (17:58:00 CET)
A multi-tool analytical practice was used for characterization of 16th century carpet manufactured in Cairo. Mild extraction method with hydrofluoric acid enabled isolation of intact flavonoids and their glycosides, anthraquinones, tannins and indigoids from fibre samples. High-performance liquid chromatography coupled to spectroscopic and mass spectrometric detectors was used for identification of natural dyes present in the historical samples. Weld, young fustic and brazilwood were identified as the dye sources in yellow thread samples. Red fibres have been colored with lac dye, whereas green fibre shades were obtained with indigo and weld. Tannin-containing plant material in combination with indigo and weld were used to obtain brown hue of thread. Four uncommon and thus-far unknown dye components were also found in the historical samples. These compounds probably represent unique fingerprint of dyed threads from this region. Scanning electron microscopy with energy-dispersive X-ray detector (SEM-EDS) and Fourier transformation infrared spectroscopy (FT-IR) were used for identification and characterization of substrates and mordants present in the historical carpet. Carbon and oxygen were detected in large quantities as a part of the wool protein. The presence of aluminum, iron and calcium indicated their usage as mordants. FT-IR analysis showed bands characteristic to woolen fibres and SEM micrographs definite structure of wool.
ARTICLE | doi:10.20944/preprints201710.0194.v1
Subject: Chemistry And Materials Science, Medicinal Chemistry Keywords: Africa; Terminalia brownii; antifungal extracts; Aspergillus, Nattrassia, Fusarium; triterpenoids; flavonoids; ellagitannins; stilbenes
Online: 31 October 2017 (09:54:35 CET)
Decoctions, macerations and fumigations of the stem bark and wood of Terminalia brownii Fresen. are used in traditional medicine for fungal infections and as pesticides on field crops and in traditional granaries in Sudan. In addition, T. brownii is commonly used for protecting wooden houses and furniture. Therefore, using agar disc diffusion and macrodilution methods, eight extracts of various polarities from the stem wood and bark were screened for their growth inhibitory effects against filamentous fungi commonly causing fruit, vegetable and grain decay, as well as infections in the immunocompromised host. Ethyl acetate extracts of the stem wood and bark gave the best antifungal activities, with MIC values of 250 µg/ml against Nattrassia mangiferae and Fusarium verticillioides, and 500 µg/ml against Aspergillus niger and Aspergillus flavus. Aqueous extracts gave almost as potent effects as the ethyl acetate extracts against the Aspergillus and Fusarium strains, and were slightly more active than the ethyl acetate extracts against Nattrassia mangiferae. Thin layer chromatography, RP-HPLC-DAD and tandem mass spectrometry (LC-MS/MS), were employed to identify the chemical constituents in the ethyl acetate fractions of the stem bark and wood. The stem bark and wood were found to have a similar qualitative composition of polyphenols and triterpenoids, but differed quantitatively from each other. The stilbene derivatives, cis- (3) and trans- (4) resveratrol-3-O-β-galloylglucoside, were identified for the first time in T. brownii. Moreover, methyl-(S)-flavogallonate (5), quercetin-7-β-O-di-glucoside (8), quercetin-7-O-galloyl-glucoside (10), naringenin-4`-methoxy-7-pyranoside (7), 5,6-dihydroxy-3`,4`,7-tri-methoxy flavone (12), gallagic acid dilactone (terminalin) (6), a corilagin derivative (9) and two oleanane type triterpenoids (1) and (2) were characterized. Our results justify the traditional uses of macerations and decoctions of T. brownii stem wood and bark for crop and wood protection and demonstrate that standardized extracts could have uses for the eco-friendly control of plant pathogenic fungi in African agroforestry systems. Likewise, our results justify the traditional uses of these preparations for the treatment of skin infections caused by filamentous fungi.
REVIEW | doi:10.20944/preprints202308.1020.v1
Subject: Biology And Life Sciences, Food Science And Technology Keywords: Southern Atlantic Diet; Anticancer; glucosinolates; sulforaphane; phenolic compounds; flavonoids; antioxidant; chemoprevention; nutragenomic; nutraceutical
Online: 14 August 2023 (09:49:55 CEST)
Scientific evidence increasingly supports the strong link between diet and health, acknowledging that a well-balanced diet plays a crucial role in preventing chronic diseases such as obesity, diabetes, cardiovascular issues, and certain types of cancer. This perspective opens the door to developing precision diets, particularly tailored for individuals at risk of developing cancer. It encompasses a vast research area and involves the study of an expanding array of compounds with multi-level "omics" compositions, including genomics, transcriptomics, proteomics, epigenomics, miRNomics, and metabolomics. We review here the components of the Southern European Atlantic Diet (SEAD) from both a chemical and pharmacological standpoint. The information sources consulted, complemented by crystallographic data from the Protein Data Bank, establish a direct link between SEAD and its anticancer properties. The data collected strongly suggest that SEAD offers an exceptionally healthy profile, particularly due to the presence of beneficial biomolecules in its foods. The inclusion of olive oil and paprika in this diet provides numerous health benefits, and science supports the anti-cancer properties of dietary supplements with biomolecules sourced from vegetables of the brassica genus. Nonetheless, further research is warranted in this field to gain deeper insights into the potential benefits of SEAD's bioactive compounds against cancer.
ARTICLE | doi:10.20944/preprints202307.1912.v1
Subject: Biology And Life Sciences, Food Science And Technology Keywords: nutrient solution; flavonoids; phenols; DPPH; ORAC; vitamins; mineral content; organic acids; sensory analysis
Online: 27 July 2023 (12:02:55 CEST)
This research presents a comparative analysis of the yield and nutritional quality of lettuce (Lactuca sativa L.) cultivated in an aeroponic system with two distinct nutrient solutions: (i) commercial hydroponic fertilizers and (ii) aquaponic water without added fertilizers. Both systems were maintained under the same controlled conditions, enabling the comparison of growth parameters, leaf area, antioxidant activity, mineral content, and sensory characteristics of the lettuce. The hydroponic system demonstrated superior performance concerning the fresh weight of lettuce head and root, leaf count, and leaf area. In contrast, the aquaponic system produced a higher dry weight of lettuce heads and a more extensive root-to-shoot ratio. Concerning nutrient concentration, the hydroponic nutrient solution composition exhibited elevated levels of NO3–, P, NH4+, and K in contrast to the aquaponic nutrient solution, which had a more significant S, Cl–, Na, and Mg content. Regarding the nutritional value, lettuce from the hydroponic system exhibited significantly higher levels of K, S, P, Zn, Fe, Mn, and vitamin B2. In contrast, lettuce from the aquaponic system exceeded with higher content of Ca, Na, Mg, Al, B, and Si. Remarkably, the lettuce cultivated in the aquaponic system demonstrated significantly enhanced total flavonoid and phenol content, and antioxidant capacity compared to its hydroponically grown counterpart.
ARTICLE | doi:10.20944/preprints202203.0328.v1
Subject: Biology And Life Sciences, Virology Keywords: Zika Virus; Flavonoids; Azadirachta indica; Molecular Docking; Molecular Dynamics Simulation; Binding free energy
Online: 24 March 2022 (09:31:59 CET)
Zika virus (ZIKV) has been characterized as one of the potential pathogens and placed under future epidemic outbreaks by the WHO. However, lack of potential therapeutics can result in uncontrolled pandemic like other human pandemic viruses; therefore, prioritized effective therapeutics development has been recommended against ZIKV. In this context, the present study adopted the strategy to explore the lead compounds from Azadirachta indica against ZIKV via concurrent inhibition of the ZIKVpro and ZIKVRdRp proteins using molecular simulations. Initially, structure-based virtual screening of 44 bioflavonoids reported in Azadirachta indica against the crystal structures of targeted ZIKV proteins resulted in the identification of top four common bioflavonoids, viz. rutin, nicotiflorin, isoquercitrin, and hyperoside. These compounds showed substantial docking energy (-7.9 to -11.01 kcal/mol) and intermolecular interactions with essential residues of ZIKVpro (His51, Asp74, and Ser135) and ZIKVRdRp (Asp540, Ile799, and Asp665) by comparison to the reference compounds, O7N inhibitor (ZIKVpro) and Sofosbuvir inhibitor (ZIKVRdRp). Long interval molecular dynamics simulation (500 ns) on the selected docked poses reveals the stability of respective docked complexes contributed by intermolecular hydrogen bonds and hydrophobic interactions. The predicted complex stability was further supported by calculated end-point binding free energy using molecular mechanics generalized born surface area (MM/GBSA) method. Consequently, the identified common bioflavonoids are recommended as promising therapeutic inhibitors of ZIKVpro and ZIKVRdRp for further experimental assessment.
ARTICLE | doi:10.20944/preprints201805.0437.v1
Subject: Chemistry And Materials Science, Medicinal Chemistry Keywords: Jatropha pelargoniifolia; alkaloids; flavonoids; coumarinolignans; diterpenes; anti-inflammatory; antinociceptive; antipyretic; free radical scavenging
Online: 30 May 2018 (06:15:42 CEST)
Extensive phytochemical and chromatographic analysis of different root fractions of Jatropha pelargoniifolia Courb. (Euphorbiaceae) resulted in the isolation and identification of 22 distinct secondary metabolite compounds. Two new compounds, 6-hydroxy-8-methoxycoumarin-7-O-β-D-glycopyranoside and (3-(2-(methylamino) ethyl)-1H-indol-2-yl) methanol, were isolated and identified for the first time from a natural source. In addition, other known compounds, such as hovetricoside C and N-methyltryptamine were isolated from Euphorbiaceae, and hordenine, N-methyltyramine, their salts, cynaroside and linarin were identified in Jatropha spp. for the first time. Some isolated metabolites, such as β-sitosterol, β-sitosterol glucoside, curcusons D and C, naringenin, apigenin, cleomiscosins B and A, spruceanol, propacin, jatrophadiketone, and uracil were previously identified in various Jatropha species. The structures of the isolated compounds were determined using different spectroscopic techniques. The anti-inflammatory, antinociceptive, antipyretic, and antioxidant activities were evaluated for some adequately available isolated compounds. Compounds showed significant antinociceptive activity compared with the standard analgesic drug indomethacin. The edema size was significantly reduced (p< 0.05–0.001) in the animals treated with low doses (5 and 10 mg/kg) of the isolated compounds compared with those treated with a high dose (100 mg/kg) of standard anti-inflammatory drug (phenylbutazone). Furthermore, all tested compounds showed a significant (p< 0.05–0.001) reduction in the rectal temperature of hyper-thermic mice.
REVIEW | doi:10.20944/preprints201706.0125.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: flavonoids; nitric oxide (•NO); nitrosation; nitrous acid; quinones; redox reactions; stomach; thiocyanic acid.
Online: 28 June 2017 (07:41:14 CEST)
Foods are mixed with saliva in the oral cavity and swallowed. During staying in the stomach, saliva is contentiously provided to mix with the ingested foods. Because a salivary component nitrite is protonated to produce active nitrous acid at acidic pH, the redox reactions of nitrous acid with phenolic compounds in foods become possible in the stomach. In the reactions, nitrous acid is reduced to nitric oxide (•NO), producing various products from phenolic compounds. In the products, stable hydroxybezoyl benzofuranone derivatives, which are produced from quercetin and its 7-O-glucoside, are included. Caffeic acid, chlorogenic acid, and rutin are oxidized to quinones and the quinones can react with thiocyanic acid derived from saliva producing stable oxathiolone derivatives. 6,8-Dinitrosocatechis are produced from catechins by the redox reaction, and the dinitrocatechins are oxidized further by nitrous acid producing the quinones, which can make charge transfer complexes with the dinitrosocatechin and can react with thiocyanic acid producing the stable thiocyanate conjugates. In this way, various products can be produced by the reactions of salivary nitrite with dietary phenolic compounds, and reactive and toxic quinones formed by the reactions are postulated to be removed in the stomach by thiocyanic acid derived from saliva.
ARTICLE | doi:10.20944/preprints202309.2058.v1
Subject: Biology And Life Sciences, Animal Science, Veterinary Science And Zoology Keywords: Caragana korshinskii Kom.; flavonoids; Taraxacum mongolicum Hand.-Mazz.; fermentation quality; antioxidant status; microbial community
Online: 29 September 2023 (04:26:21 CEST)
The present study was to investigate effects of total flavonoids from Taraxacum mongolicum Hand.-Mazz. (FT) on fermentation quality, antioxidant status and microbial community of Caragana korshinskii Kom. (CK) silage. CK was ensiled with no additive (CON), 1% FT and 2% FT on a fresh weight (FW) basis for 60 days. The results showed that 1% FT and 2% FT groups displayed higher DM content than CON group, and 2% FT group had the best effect on nutrient preservation. Compared with CON and 1% FT groups, 2% FT group exhibited the best silage fermentation quality and the highest antioxidant activity, including increased lactic acid, acetic acid concentrations and the activities of antioxidant enzymes, as well as decreased pH and the ammonia nitrogen (NH3-N) concentration. Moreover, 2% FT addition significantly affected the microbial community, such as increased abundance of Lactobacillus and decreased abundances of Pseudomonas and unidentified Cyanobacteria. The abundances of Lactobacillus parafarraginis and Lactobacillus brevis were negatively correlated to pH, while they were positively correlated with T-AOC, GSH-Px and CAT activities. In conclusion, 2% FT may be used as additives to inhibit the growth of undesirable microorganisms and promote fermentation quality and antioxidant activity of CK silage.
ARTICLE | doi:10.20944/preprints202004.0152.v1
Subject: Physical Sciences, Fluids And Plasmas Physics Keywords: citrus fruits; coronavirus; COVID-19; flavonoids; hesperetin; hesperidin; hydrodynamic cavitation; pectin; SARS-CoV-2.
Online: 9 April 2020 (12:47:09 CEST)
Based on recent computational and experimental studies, hesperidin, a bioactive flavonoid abundant in citrus peel, stands out for its high binding affinity to the main cellular receptors of SARS-CoV-2, outperforming drugs already recommended for clinical trials. Thus, it is very promising for prophylaxis and treatment of COVID-19, along with other coexistent flavonoids such as naringin, which could help restraining the pro-inflammatory overreaction of the immune system. Controlled hydrodynamic cavitation processes showed the highest speed, effectiveness and efficiency in the integral and green aqueous extraction of flavonoids, essential oils and pectin from citrus peel waste. After freeze-drying, the extracted pectin showed high quality and excellent antioxidant and antibacterial activities, attributed to flavonoids and essential oils adsorbed and concentrated on its surface. This study reviews the recent evidence about hesperidin as a promising molecule, and proposes a feasible and affordable process based on hydrodynamic cavitation for the integral aqueous extraction of citrus peel waste resulting in hesperidin-rich products, either aqueous extracts or pectin tablets. The uptake of this process on a relevant scale is urged, in order to achieve large-scale production and distribution of hesperidin-rich products. Meanwhile, experimental and clinical studies could determine the effective doses either for therapeutic and preventive purposes.
REVIEW | doi:10.20944/preprints202211.0320.v1
Subject: Biology And Life Sciences, Anatomy And Physiology Keywords: aging; longevity; supplements; geroprotectors; SIRT1; NAD+; NMN; resveratrol; nutraceuticals; age-related diseases; flavonoids; senolytics; healthspan
Online: 17 November 2022 (02:51:11 CET)
Disrupted biological function, manifesting through the hallmarks of aging, poses as one of the largest threats to healthspan and risk of disease development, such as metabolic disorders, cardiovascular ailments, and neurodegeneration. In recent years, numerous geroprotectors, senolytics, and other nutraceuticals have emerged as potential disruptors of aging and may be viable interventions in the immediate state of human longevity science. In this review, we focus on the decrease of nicotinamide adenine dinucleotide (NAD+) with age and the supplementation of NAD+ precursors, such as nicotinamide mononucleotide (NMN) or nicotinamide riboside (NR), in combination with other geroprotective compounds to restore youthful NAD+ levels. Furthermore, these geroprotectors may enhance the efficacy of NMN supplementation while concurrently providing their own numerous health benefits. By analyzing the prevention of NAD+ degradation through inhibition of CD38 or supporting protective downstream agents of SIRT1, we provide a potential framework of the CD38/NAD+/SIRT1 axis through which geroprotectors may enhance the efficacy of NMN supplementation and reduce the risk of age-related diseases, thereby potentiating healthspan in humans.
REVIEW | doi:10.20944/preprints202106.0305.v1
Subject: Medicine And Pharmacology, Immunology And Allergy Keywords: dietary flavonoids; cardioprotective effects; ROS scavenging; myocardial dysfunction; bioavailability and drug metabolism; toxicity; drug discovery
Online: 11 June 2021 (08:44:01 CEST)
Flavonoids comprise a large group of structurally diverse polyphenolic compounds of plant origin and are abundantly found in human diet such as fruits, vegetables, grains, tea, dairy products, red wine and so on. Major classes of flavonoids include flavonols, flavones, flavanones, flavanols, anthocyanidins, isoflavones, and chalcones. Owing to their potential health benefits and medicinal significance, flavonoids are now considered as an indispensable component in a variety of medicinal, pharmaceutical, nutraceutical, and cosmetic preparations. However, flavonoids play a significant role in preventing cardiovascular diseases (CVDs), which could be mainly due to their antioxidant, antiatherogenic, and antithrombotic effects. Epidemiological and in vitro/in vivo evidences of antioxidant effects support the cardioprotective function of dietary flavonoids. Further, the inhibition of LDL oxidation and platelet aggregation following regular consumption of food containing flavonoids and moderate consumption of red wine might protect against atherosclerosis and thrombosis. A study suggests that daily intake of 100 mg of flavonoids through diet may reduce the risk of developing morbidity and mortality due to coronary heart disease (CHD) by approximately 10%. This review summarizes dietary flavonoids with their sources and potential health implications in CVDs including various redox-active cardioprotective (molecular) mechanisms with antioxidant effects. Pharmacokinetic (oral bioavailability, drug metabolism), toxicological and therapeutic aspects of dietary flavonoids are also addressed herein with future directions for the discovery and development of useful drug candidates/ therapeutic molecules.
ARTICLE | doi:10.20944/preprints202008.0106.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: citrus pectin; lemon; grapefruit; IntegroPectin; flavonoids; citrus terpenes; polyphenols; antimicrobial resistance; Staphylococcus aureus; Pseudomonas aeruginosa
Online: 5 August 2020 (03:34:49 CEST)
Grapefruit and lemon pectin obtained from the respective waste citrus peels via hydrodynamic cavitation in water only are powerful, broad-scope antimicrobial alternatives to antibiotics against Gram-negative and -positive pathogens. Dubbed IntegroPectin, these pectic polymers functionalized with citrus flavonoids and terpenes show superior antimicrobial activity when compared to commercial citrus pectin. Similarly to commercial pectin, lemon IntegroPectin determined ca. 3 log reduction of Staphylococcus aureus cells, while an enhanced activity of commercial citrus pectin was detected in the case of Pseudomonas aeruginosa cells with a minimal bactericidal concentration (MBC) of 15 mg mL-1. Although grapefruit and lemon IntegroPectin share equal MBC in the case of P. aeruginosa cells, grapefruit IntegroPectin shows boosted activity upon exposure of S. aureus cells with a 40 mg mL-1 biopolymer concentration being sufficient to achieve complete killing of the bacterial cells. Insight on the mechanism of action of these biocompatible antimicrobials and their effect on bacterial cells, at the morphological level, were obtained indirectly through Fourier Transform Infrared spectroscopy and directly through scanning electron microscopy. In the era of antimicrobial resistance, these results are of great societal and sanitary relevance as they open new avenues to develop innovative antimicrobials for the treatment of polymicrobial infections unlikely to develop drug resistance.
ARTICLE | doi:10.20944/preprints201904.0177.v1
Subject: Chemistry And Materials Science, Chemical Engineering Keywords: lipid peroxidation; membrane elasticity; mesoporous silica nanoparticles; myricetin; myricitrin; nanomechanics; protective effects of flavonoids; quercetin
Online: 16 April 2019 (09:54:03 CEST)
Flavonoids, polyphenols with anti-oxidative activity have high potential as novel therapeutics for neurodegenerative disease, but their applicability is rendered by their poor water solubility and chemical instability under physiological conditions. In this study, this is overcome by delivering flavonoids to model cell membranes (unsaturated DOPC) using prepared and characterized biodegradable mesoporous silica nanoparticles, MSNs. Quercetin, myricetin and myricitrin have been investigated in order to determine the relationship between flavonoid structure and protective activity towards oxidative stress i.e. lipid peroxidation induced by addition of hydrogen peroxide and/or Cu2+ ions. Among investigated flavonoids, quercetin showed the most enhanced and prolonged protective anti-oxidative activity. The nanomechanical (Young modulus) measurement of the MSNs treated DOPC membranes during lipid peroxidation confirmed attenuated membrane damage. By applying combination of experimental techniques (AFM, force spectroscopy, ELS, DLS), this work generated detailed knowledge about the effects of flavonoid loaded MSNs on the elasticity of model membranes, especially under oxidative stress conditions. Results from this study will pave the way towards the development of innovative and improved markers for oxidative stress-associated neurological disorders. In addition, the obtained could be extended to designing effective delivery systems of other high potential bioactive molecules with an aim to improve human health in general.
ARTICLE | doi:10.20944/preprints202103.0707.v1
Subject: Chemistry And Materials Science, Analytical Chemistry Keywords: Grape processing waste; Polyphenols; Green extraction; Microwave-hydrodiffusion and gravity, Enocyanin; Resveratrol; Flavonoids; Anthocyanins; Wine pomace
Online: 29 March 2021 (16:06:18 CEST)
The extraction of grape processing waste (wine pomace) via microwave-hydrodiffusion and gravity (MHG) from three different cultivars grown in Sicily (Syrah, Perricone and Nero d’Avola) rapidly affords aqueous extracts highly concentrated in valued biophenols including flavonoids, anthocyanins and phenolic acids. The method does not employ organic solvent, acid or base and does not require grinding or freeze drying of the wine pomace nor separation of the grape skins from seeds and stem. All the extracts have a pronounced stability as shown by their red-violet color fully retained after storage for more than a year (15 months) in freezer under air. Concentrations of phenolics up to 2000 ppm were detected in the aged extracts of Sicily’s local cultivar Perricone, which also has the highest content of flavonoids. These findings provide a simple and economically viable extraction route to biophenol-rich red extracts that can be used as food colorants as well as to formulate nutraceutical, cosmetic and personal care products starting from an agricultural by-product available in >10 million tonne yearly amount.
REVIEW | doi:10.20944/preprints202105.0131.v1
Subject: Biology And Life Sciences, Anatomy And Physiology Keywords: rhizobia; legume; rhizobium-legume symbiosis; exopolysaccharide synthesis; quorum sensing (QS); nodulation; nod regulon; flavonoids; RosR/MucR; SyrM
Online: 7 May 2021 (09:29:45 CEST)
Abstract: Rhizobia are soil proteobacteria able to engage in a nitrogen-fixing symbiotic interaction with legumes which involves root rhizobial infection and bacterial invasion of new organs formed by the plant in response to the presence of appropriate bacterial partners. This interaction relies on a complex molecular dialogue between both symbionts. Bacterial N-acetyl-glucosamine oligomers called Nod factors are indispensable in most cases for early steps of the symbiotic interaction. In addition, different rhizobial surface polysaccharides, such as exopolysaccharides (EPS), may also be symbiotically relevant. EPS are acidic polysaccharides located out of the cell with little or no cell association that carry out important roles both in free-life and in symbiosis. EPS production is very complexly modulated and, frequently, co-regulated with that of Nod factors, but the type of co-regulation varies depending on the rhizobial strain. Many studies point out a signalling role of EPS-derived oligosaccharides in root infection and nodule invasion but, in certain symbiotic couples, EPS can be dispensable for a successful interaction. In summary, the complex regulation of the production of rhizobial EPS varies in different rhizobia and the relevance of this polysaccharide in symbiosis with legumes depends on the specific interacting couple.
ARTICLE | doi:10.20944/preprints202006.0023.v1
Subject: Chemistry And Materials Science, Analytical Chemistry Keywords: Nymphaea lotus L.; stamen; ultrasound-assisted extraction; macroporous resin (MPR) purification; in vitro; in cellulo; antioxidant; flavonoids
Online: 4 June 2020 (03:59:58 CEST)
Nymphaea lotus L. is the medicinal plant that has long been used as food, cosmetic and traditional medicines in Africa and Asia since the ancient time. Its flavonoids and other interesting phytochemical compounds from rhizome, leaf, and the whole flowers have been reported in the previous published researches. However, stamens, which are essential for reproductive functions, may also represent new alternative sources of potential antioxidant flavonoids as investigated in this study. The innovative green chemistry method i.e. ultrasound-assisted extraction (USAE) as well as macroporous resin (MPR) purification procedure were employed in this current research. The optimal ultrasound-assisted extraction condition is 90 % (v/v) aqEtOH with 34.65 khz ultrasonic frequency and 46 minutes of extraction time. Comparing with heat reflux extraction (HRE) conventional method, the significant gain of 1.35 total flavonoids content was obtained using optimized USAE conditions, jumping to 2.80 when this USAE associated with MPR purification. Not only in vitro cell free antioxidant activity of N. lotus stamen extracts, but also in cellulo antioxidant investigation using yeast model showed the same trend to indicate that the best antioxidant flavonoid can be found in USAE coupled with MPR purification. Moreover, the key antioxidant genes expression in yeast model such as SIR2 and SOD2 were also expressed at the highest level in yeast cell treated with the extract from USAE together with MPR purification. Consequently, it can be seen that the USAE combined with MPR purification can help to enhance the flavonoids antioxidant potential of the stamens extract from this medicinal species.
REVIEW | doi:10.20944/preprints202310.2051.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: higher plants; reactive oxygen species; antioxidants; isoprenoids; plastoquinone; carotenoids; tocopherol; ubiquinone; flavonoids; ascorbic acid; glutathione; transgenesis; CRISPR/Cas9
Online: 31 October 2023 (12:21:23 CET)
Plants are exposed to a variety of abiotic and biotic stresses leading to increased formation of reactive oxygen species (ROS) in plant cells. ROS are capable of oxidizing proteins, pigments, lipids, nucleic acids, and other cell molecules, disrupting their functional activity. During the process of evolution, numerous antioxidant systems were formed in plants, including antioxidant enzymes and low-molecular-weight non-enzymatic antioxidants. Antioxidant systems perform neutralization of ROS and therefore prevent oxidative damage of cell components. In the present review, we focus on the biosynthesis of non-enzymatic antioxidants in higher plant cells such as ascorbic acid (vitamin C), glutathione, flavonoids, isoprenoids, including carotenoids, tocopherol (vitamin E), ubiquinone and plastoquinone. Their functioning and their reactivity with respect to individual ROS are described. The review is also devoted to the modern genetic engineering methods, which are widely used to change the quantitative and qualitative content of the non-enzymatic antioxidants in cultivated plants. These methods allow to obtain various plant lines with given properties in a rather short time. The most successful approaches for plant transgenesis and plant genome editing for the enhancement of the biosynthesis and the content of these antioxidants are discussed.
ARTICLE | doi:10.20944/preprints202308.0064.v1
Subject: Chemistry And Materials Science, Medicinal Chemistry Keywords: Pomegranate Peels; Green Extraction; Food-Waste Valorization; Polyphenols; Antioxidant Activity; Flavonoids; Anthocyanins; Green Metrics; Energetic Evaluation; Biological Activity
Online: 1 August 2023 (10:41:00 CEST)
Pomegranate (Punica granatum L.) is well known for its high content in bioactives including polyphenols, flavonoids and tannins, which have been shown to exhibit a wide range of biological activity such as antioxidant, antimicrobial and anticancer effects. It is worth noting that the majority of these molecules are found in the peels (PP), which are usually disposed of after processing, causing a significant amount of waste, amounting to more than 3.6 million t/y. This work investigates MW-assisted extraction (MAE) in water for the recovery of antioxidants from PP, including the optimization of temperature and extraction times. The total phenolics, anthocyanin, flavonoid and tannin contents of the recovered extracts have been determined, as have their antioxidant activities, which were found to be 356.35 mgGAE/gextr., 303.97 µgCy3G/gextr., 37.28 mgQE/gextr., 56.48 mgGAE/gextr. and 1.43 µmolTE/gextr., respectively (according to the adopted reference). All results have been compared with those obtained using a conventional protocol. In addition, the potential for water recycling by means of nanofiltration downstream in optimized MAE has been investigated, leading to overall water reuse of approx. 75%. Energy consumption (20.92W/mgGAE) and the common green metrics, RME, E-Factor and PMI (PME), have been considered in evaluating the proposed PP valorization strategy. Finally, the biological activity of the main products has been assessed. The antimicrobial properties of the PP extracts against three Gram-positive and three Gram-negative bacteria, and their antiproliferative activity towards human cancer cells have been tested. The S. aureus bacteria was the most susceptible to the PP extracts. All tested products displayed antiproliferative activity in HeLa cells when higher concentrations were tested, with D-PP/NF being the most effective. This result was also confirmed in a clonogenic analysis, which generally indicated the possible anti-cancer activity of pomegranate peel extracts obtained using this green approach.
ARTICLE | doi:10.20944/preprints201812.0175.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: Abies Alba Mill.; antioxidant activity; coniferous trees; essential oils; flavonoids; food preservation; green extraction; hydrodynamic cavitation; nutraceutics; polyphenols
Online: 17 December 2018 (07:07:56 CET)
Extracts from parts of coniferous trees have received increased interest due to their valuable bioactive compounds and properties, useful for plenty of experimental and consolidated applications, in fields comprising nutraceutics, cosmetics, pharmacology, food preservation, and stimulation of plant growth. However, the variability of the bioactive properties, the complexity of the extraction methods, and the use of potentially harmful synthetic chemicals, still represent an obstacle to the spreading of such valuable natural compounds. Hydrodynamic cavitation is emerging as a promising innovative technique for the extraction of precious food components and by-products from waste raw material of the agro-food production chain, which can improve processing efficiency, reduce resource consumption, and produce healthy, high-quality products. In this study, a process based on controlled hydrodynamic cavitation was applied for the first time to the production of aqueous solutions of silver fir (Abies Alba Mill.) needles with enhanced antioxidant activity. The observed levels of the in vitro antioxidant activity, comparable or higher than those found for reference substances, pure extracts, and other water extracts and beverages, highlight the very good potential of the HC process for the creation of solvent-free, aqueous solutions endowed with bioactive compounds extracted from silver fir needles.
REVIEW | doi:10.20944/preprints202306.1113.v1
Subject: Medicine And Pharmacology, Pathology And Pathobiology Keywords: Inflammatory bowel disease; Colitis-associated colorectal cancer; exogenous frees hemoglobin alpha chain; Fenton reaction; DNA damage; haptoglobin; deferoxamine; flavonoids; hydrogen peroxide; hygiene; iron; nanomedicine; oxidative stress; polyphenol; pharmaceutical therapy
Online: 16 June 2023 (07:11:38 CEST)
The aggregate aftermath of persistent inflammation in patients with inflammatory bowel disease (IBD) places them at increased risk for the advancement to colitis-associated colorectal cancer (CACRC). CACRC is preceded by IBD, the highly heterogenous, pharmacologically incurable, pertinacious, reverting/worsening, and immune-mediated inflammatory pathologies of the colon and rectum. The molecular and immunological basis of CACRC is highly correlated with the length/duration and stringency/severity of colon inflammation predisposed by the exogenous/free hemoglobin alpha chain (HbαC) the byproduct of infiltrating immune cells, extravasated erythrocytes, and macrophage erythrophagocytosis. The exogenous free HbαC prompts oxygen-free radical-arbitrated DNA damage (DNAD) through increased cellular reactive oxygen species (ROS) exacerbated by decreased tissue antioxidant defenses. Mitigation of Fenton reaction via pharmaceutical therapy would attenuate the ROS, promote apoptosis, DNAD repair, and subsequent prevent the incidence of CACRC. Three pharmaceutical options that attenuate hemoglobin toxicity include haptoglobin, deferoxamine, and flavonoids (vitamins C/E). Haptoglobin’s clearance rare from plasma is inversely correlated with its size; the smaller the size, the faster the clearance. Thus, the administration of Hp1-1 may prove to be beneficial. Furthermore, deferoxamine’s hydrophilic structure limits its ability to cross cell membranes. Thus, it may be beneficial if administered intracellularly to avoid the higher plasma concentrations and longer incubation periods associated with extracellular administration. Finally, the effectiveness of flavonoids and natural herb antioxidants is associated with high reactivity of hydroxyl substituents. Multiple analyses are currently underway to assess the clinical context of CACRC and outline the molecular basis of HbαC-induced ROS pathogenesis by exposing colonocytes and/or colonoids to HbαC. These cells are then treated with haptoglobin, deferoxamine (DFO), and flavonoids in order to separate free HbαC and measure their impact on hydroxyl radical formation therapies. The molecular pathogenesis of sporadic colorectal cancer (SCRC) i.e., “inflammation-dysplasia-carcinoma” progression sequence is well described, but the immunopathogenesis of CACRC herein reviewed is broadly still in prodromal stage/phase to be validated and understood. Therefore this timely review outlines the molecular and immunological basis of disease pathogenesis and the pharmaceutical intervention as a protective measure for CACRC.