ARTICLE | doi:10.20944/preprints202010.0181.v1
Subject: Chemistry, Analytical Chemistry Keywords: Ethiopia; milk; aflatoxin; Awi zone; HPLC-FLD; Aspergillus
Online: 8 October 2020 (15:53:52 CEST)
The aim of this study, therefore, provides information about Aflatoxin levels in raw cow’s milk in Injibara Town of Awi Administrative zone by using HPLC-FLD. A good linearity of standard calibration was found for AFM1 at a range of 0.5–7 µg/L. Regression coefficient (R2) values were 0.9999, whereas slope and intercept were 2.5278 and 0.1012, respectively. The average recoveries for the spiked samples were range from76.62– 90.98 % and the RSD values ranged between 2.55–7.36 %. The results showed that 15 % of samples (3 out of 20) were contaminated with AFM1 in the range of 0.046–0.22 µg/L. The average contamination level was 0.121 µg/L. The determined mean values of AFM1 in the collected milk samples were above the standard limit of the European Commission and lower than the level established by United States regulations. Further monitoring of Aflatoxin in milk samples from different regions of the country is justified to conclusively determine the actual safe/risks and possibly low Aflatoxins-risk milk production areas.
ARTICLE | doi:10.20944/preprints202009.0607.v1
Subject: Chemistry, Analytical Chemistry Keywords: Milk Serum; whey proteins; RP-HPLC-UV; free amino acids; RP-HPLC-FLD; antimicrobial study
Online: 25 September 2020 (11:45:09 CEST)
The aim of this study was characterization of some dairy drinks based on Milk Serum regarding major whey proteins (WP) and free amino acids (FAAs) using reversed phase high performance liquid chromatographic (RP-HPLC) methods. The studied WP, -lactalbumin (-La), bovine serum albumin (BSA), -lactoglobulin A (-Lg A) and -lactoglobulin B (-Lg B) were separated on Aeris XB-C18 column at 214 nm detection. The RP-HPLC method was validated by selectivity, linearity (R2 ≥0.99), sensitivity (LOQ, 1.35–10.08 µg mL−1), accuracy (recovery 96.79-103.07%) and precision (% RSD ≤ 4.13%). The total studied WP in studied dairy drinks varied between 1.42 and 3.047 g·L-1. The chromatographic profile of FAAs (aspartic acid, glutamic acid, serine, histidine, arginine, glycine, threonine, alanine, tyrosine, cysteine, tryptophan, methionine, valine, phenylalanine, isoleucine, leucine and lysine) was determined in lyophilized concentrate of Milk Serum by RP-HPLC using pre-column derivatization reaction with orthophthalaldehyde (OPA). The total studied FAAs in studied samples varied between 1.103 and 1.119 mg·g-1. Moreover, the Milk Serum showed bacteriostatic activity against two bacterial strains Escherichia coli and Staphylococcus aureus. The obtained results confirm that dairy drinks based on the Milk Serum constitutes a valuable sources of bioactive components with benefits for human healthy nutrition.
REVIEW | doi:10.20944/preprints202201.0277.v1
Subject: Medicine & Pharmacology, Pharmacology & Toxicology Keywords: HPLC; TDM; ceftriaxone; daptomycin; linezolid
Online: 19 January 2022 (14:29:36 CET)
Under the Japanese health insurance system, medicines undergoing therapeutic drug monitoring (TDM) can be billed for medical fees if they meet the specified requirements. In Japan, TDM of vancomycin, teicoplanin, aminoglycosides, and voriconazole, which are used for the treatment of infectious diseases, is common practice. This means the levels of antimicrobial agents are measured in-house using chromatography. This review describes personalized medicine based on the use of chromatography as a result of the current situation in Japan.
SHORT NOTE | doi:10.20944/preprints201703.0219.v1
Online: 30 March 2017 (16:58:33 CEST)
We cultured Parmelina carporrhizans and P. quercina in Corn Meal Agar and 0.2% glucose Malt Yeast Agar for 160 days. Chemosyndrome of natural thalli and mycobiont cultures were analyzed by HPLC. Lecanoric acid, atranorin, chloratranorin and ergosterol were detected in P. carporrhizans thalli, while lecanoric acid, chloratranorin and aliphates were found in P. quercina thalli. The secondary methabolites pattern between thalli and mycobiont culture was completely different in both species. Both species secreted the phenalenone myeloconone C in culture media and was also detected in P. quercina mycobiont aggregates. Interestingly, the phenolic compounds produced by the mycobiont culture of P. carporrhizans are related to those produced by natural thallus by the same biosynthetic pathway, while the chemosyndrome of P. quercina mycobiont implies switch of biosynthetic pathway from acetate-polymalonate pathway to shikimic acid pathway, with pulvinic acid as major compound of mycobiont culture. The role of Myelochonone C, confluentic acid and pulvinic acid produced by mycobiont culture is discussed as possible adaptive vantage in field as photoprotective agent or as byproduct result of stressing artificial culture conditions.
ARTICLE | doi:10.20944/preprints202201.0405.v1
Subject: Chemistry, Food Chemistry Keywords: mangosteen; phenolic components; HPLC; quantification; fingerprint
Online: 26 January 2022 (18:46:41 CET)
The extracts of Garcinia mangostana L. (mangosteen) are traditionally used for medicinal purposes in Asia. Phenols and xanthones are the two main phenolic compounds with anti-inflammatory activities in the pericarps of mangosteen. A simple and economic reverse-phase high-performance liquid chromatography (RP-HPLC) method has been developed for the simultaneous quantification of phenols (catechin, epicatechin, and procyanidin B2) in mangosteen. The mobile phase was acetonitrile: water (12:88) at 30°C, the flow rate was 1 mL/min, and the detection wavelength was 230 nm. The results showed good linear relationships for catechin from 50-250 ng and for epicatechin and procyanidin B2 from 250-1250 ng. The RP-HPLC fingerprint determination method of total xanthones in mangosteen was also established to provide a new method for quality control of mangosteen extract. The mobile phase was a methanol-water gradient elution at 30°C, the flow rate was 1 mL/min, and the detection wavelength was 320 nm. The similarity of fingerprints of 10 batches of total xanthones was more than 0.90. These methods had good precision, reproducibility, and stability and can be applied in the quality control of mangosteen extracts for medicinal purposes.
ARTICLE | doi:10.20944/preprints201611.0075.v3
Subject: Chemistry, Analytical Chemistry Keywords: azithromycin; HPLC; robust; isocratic; drug stability; degradation products
Online: 4 January 2017 (10:08:52 CET)
A simple, isocratic and robust RP-HPLC method for the analysis of azithromycin was developed, validated and applied for the analysis of bulk samples, tablets and suspensions. The optimum chromatographic conditions for separation were established as mobile phase comprising of acetonitrile-0.1M KH2PO4 pH 6.5-0.1M tetrabutyl ammonium hydroxide pH 6.5-water (25:15:1:59% v/v/v/v) delivered at a flow rate of 1.0 ml/min. The stationary phase consisted of reverse-phase XTerra® (250 mm× 4.6 mm i.d., 5 µm particle size) maintained at a temperature of 43 °C with a UV detection at 215 nm. The method was found to be linear in the range 50-150% (r2=0.997). The limits of detection and quantification were found to be 0.02% (20 µg) and 0.078% (78 µg) respectively with a 100.7% recovery of azithromycin. Degradation products of azithromycin in acidic and oxidative environments at 37 °C were resolved from the active pharmaceutical ingredient and thus the method is fit for the purpose of drug stability confirmation.
ARTICLE | doi:10.20944/preprints202211.0072.v1
Online: 3 November 2022 (07:47:15 CET)
Artic root is a well-known plant adaptogen with multipotential pharmacological properties. Thin-layer chromatography (TLC) – screening followed by diode-array high-performance liquid chromatography and nuclear magnetic resonance spectroscopy proved to be a reliable and convenient method for simultaneous determination of quality of various herbal raw materials and supplements. This combination allowed for comparing and differentiating arctic root samples as well as defining their authenticity. The study provided information on the chemical and biological properties of the seven chosen samples as well as qualitative and quantitative evaluation of the quality markers: rosavin, salidroside, and p-tyrosol. The absence of rosavin, salidroside, and p-tyrosol in three samples was detected using TLC-screening and confirmed by HPLC-DAD and NMR. The paper highlighted the importance of quality control and strict regulation for herbal medicine supplements and preparations.
ARTICLE | doi:10.20944/preprints202107.0229.v1
Subject: Medicine & Pharmacology, Allergology Keywords: HPLC; NSAIDs; Isocratic; Short column; Drug mixture
Online: 9 July 2021 (15:23:57 CEST)
Nonsteroidal anti-inflammatory drugs (NSAIDs), which block the activity of cyclooxygenase (COX) isoenzymes and inhibit the synthesis of prostaglandin, have been used for pain relief. We have developed a method to separate a mixture of three NSAIDs, such as aspirin, paracetamol, and naproxen, using reverse-phase high-performance liquid chromatography (RP-HPLC). An isocratic mobile phase consisting of acidic water and acetonitrile was selected to run at a low flow rate, such as 0.8 mL/min. The mixture of three NSAIDs was injected at a low volume into a C18 column that was 150 mm in length and characterized using a UV detector at 230 nm. We identified three peaks in the chromatogram indicating the three compounds. The elution time of the peaks was less than 10 minutes. To identify multiple peaks on the isocratic flow using a short column, further studies are required regarding the proposed method to generate microfluidic devices for nanoLC.
ARTICLE | doi:10.20944/preprints202008.0025.v1
Subject: Chemistry, Analytical Chemistry Keywords: HPLC method; Curcumin; Quercetin; Thermal analysis; Nanoemulsion
Online: 2 August 2020 (12:15:13 CEST)
Biphasic oily/water nanoemulsions have been proposed as delivery systems for the intranasal administration of curcumin (CUR) and quercetin (QU), due to their high drug entrapment efficiency, the possibility of simultaneous drug administration and protection of the encapsulated compounds from the degradation. To better understand the physicochemical and biological performance of the selected formulation simultaneously co-encapsulating CUR and QU, a stability test of the compounds mixture was firstly carried out using X-ray powder diffraction and thermal analyses, such as differential scanning calorimetry (DSC) and thermogravimetric analyses (TGA). The determination and quantification of the encapsulated active compounds was then required being an essential tool for the development of innovative nanomedicines. Thus, a new HPLC–UV/Vis method for the simultaneous determination of CUR and QU in the nanoemulsions and their evaluation in stability studies in simulated biological fluids was developed and validated. The X-ray diffraction analyses demonstrated that no interaction between the mixture of active ingredients, if any, is strong enough to take place in the solid state. Moreover, the thermal analysis demonstrated that the CUR and QU are stable in the nanoemulsion production temperature range. The proposed analytical method for the simultaneous quantification of the two actives was selective and linear for both compounds in the range of 0.5 – 12.5 µg/mL (R2 > 0.9997), precise (RSD below 3%), robust and accurate (recovery 100 ± 5 %). The method was validated in accordance with ICH Q2 R1 “Validation of Analytical Procedures” and CDER-FDA 2validation of chromatographic methods” guideline. Furthermore, the low detection (LOD < 0.005 µg/mL for CUR and <0.14 µg/mL for QU) and quantification limits (LOQ < 0.017 µg/mL for CUR and < 0.48 µg/mL for QU) of the method were suitable for the application to drug release and permeation studies planned for the development of the nanoemulsions. The method was then applied for the determination of nanoemulsions CUR and QU encapsulation efficiencies (> 99%), as well as for the stability studies of the two compounds in simulated biological fluids over time. The proposed method represents, to our knowledge, the only method for the simultaneous quantification of CUR, and QU in nanoemulsions.
ARTICLE | doi:10.20944/preprints202206.0126.v1
Online: 8 June 2022 (11:03:04 CEST)
The aim of this study, for determination of verteporfin in real samples (simulated body fluid, and simulated tears, 0.9% isotonic sodium chloride solution, Lactated Ringer IV solution for infusion, 5% dextrose IV solution for infusion, lemon juice and drinking water) was the method validation and to examined by HPLC-DAD-UV. Metod validation parameters such as specificity, linearity, precision, accuracy, robustness, limit of detection (LOD) and limit of quantitation (LOQ) for verteporfin were validated and developed according to the International Conference on Harmonization (ICH) Q2 R1 guidelines. The LOD and LOQ for verteporfin were found 0.06 µg/L and 0.2 µg/L, respectively. The recovery values of the optimization and validation for verteporfin were found in the range of 97.5-100.7%. The relative standard deviations (RSD) for vertepofin were <1%. The developed method was successfully applied to real samples with high accuracy and the recoveries (%) from real samples were 99.9, 100, 98.2, 99.2, 99.4, 98.8 and 99.4, respectively.
ARTICLE | doi:10.20944/preprints201806.0178.v1
Subject: Biology, Animal Sciences & Zoology Keywords: NSAIDs; salicylic acid; sodium salicylate; HPLC; sheep; pharmacokinetics
Online: 12 June 2018 (09:35:41 CEST)
The pharmacokinetics of salicylic acid (SA) in sheep was evaluated following intravenous (IV) and oral administration of sodium salicylate (sodium salt of salicylic acid) at different doses. Six healthy sheep were administered sodium salicylate (SS) IV at doses of 10, 50, 100 and 200 mg/kg body weight and another six sheep were drenched with 100 and 200 mg/kg of SS orally. Both studies were randomised crossover trials. A one-week washout period between each treatment was allowed in both studies. Blood samples were collected at 0, 15, 30 minutes and 1, 2, 4 and 6 hours after IV and oral SS administrations. Plasma SA concentrations were determined using high performance liquid chromatography with diode array detection method. Pharmacokinetic variables were calculated in a non-compartmental model. The elimination half-life (T1/2 el) of SA after IV administration of 200 mg/kg SS was 1.16 ± 0.32 hours. Mean bioavailability of SA was 64%, and mean T1/2 el was 1.90 ± 0.35 hours, after 200 mg/kg of oral SS. The minimum plasma SA concentration (16.8 µg/mL) required to produce analgesia in humans was achieved after IV administration of 100 and 200 mg/kg SS in sheep for about 0.17 hour in this study. Experiments on pharmacokinetic-pharmacodynamics modelling are required to determine the actual effective plasma concentration range of SA in sheep.
ARTICLE | doi:10.20944/preprints201802.0161.v2
Subject: Chemistry, Analytical Chemistry Keywords: Guayule; Parthenium argentatum Gray; resin; guayulins; RP-HPLC
Online: 22 March 2018 (03:19:59 CET)
Guayule (Parthenium argentatum Gray) is a shrub native of the arid regions of Mexico. In the last decades, significant attention for its cultivation has risen because it is the raw material for the production of hypoallergenic natural rubber. Guayule biomass contains also high amounts of resin, which is not normally exploited in any way. Among other sesquiterpenic esters, guayulins (i.e. the parteniol esters of cinnamic acid, guayulin A, or of anisic acid, guayulin B) are contained in resin. In addition, minor amounts of guayulin C and guayulin D are formed by degradation/oxidation of guayulins A and B, respectively. Guayulins likely act as cinnamate and p-anisate reservoirs for Guayule shrub, in addition, it has been postulated that they might have a key role in the chemical defense system of Guayule. Furthermore, it seems reasonable that guayulins may possess significant biological properties (e.g. antibacterial and anticancer activities), in close analogy with those shown by sesquiterpene lactones contained in many other species of Parthenum genus. As a matter of fact, guayulins A and B play an important role in the synthesis of antineoplastics used in breast cancer treatment. In this contribution we propose an original and validated RP-HPLC approach to the simultaneous quantification of guayulins A, B, C and D. The procedure of resin extraction from Guayule biomass has been optimized in terms of both extraction method and solvent. RP-HPLC separation has been accomplished by an Ascentis® C18 column under isocratic elution with a 80:20 (v:v) acetonitrile:water mixture. Validation was carried out in terms of limits of detection and quantification, linearity, precision, and trueness. Finally, the method was tested with a number of fresh and seasoned samples of spontaneous Guayule shrub from Mexico.
ARTICLE | doi:10.20944/preprints201803.0051.v1
Subject: Medicine & Pharmacology, Nutrition Keywords: glutamine; perioperative period; bypass surgery; intestine surgery; HPLC
Online: 7 March 2018 (05:21:29 CET)
Glutamine is the main amino acid which is substrate for gluconeogenesis in postoperative period. It is suggested that this leads to a substantial and a long-term decline in glutamine concentration. Glutamine is a source of energy for the synthesis of nucleotides, lymphocytes and cells of gastrointestinal tract. In this study, 79 patients were qualified to a coronary artery bypass surgery (Group I) or a surgery in the large intestine area (Group II). The objectives of this study were: evaluation of the impact of surgical procedures on the serum concentration of glutamine of the operated patients, assessment of gender, weight and BMI impact on glutamine concentration and analysis of the correlation between glutaminę serum concentration and laboratory parameters. The mean concentration of glutamine before surgery, the 3rd and 5th day after surgery was higher in Group I. CRP level in the 3rd and 5th postoperative day was higher in Group II. There were no significant differences betweengroups when it comes to BMI and the concentration of CRP (p <0.05). Glutamine concentration depends on the severity of inflammation, the operated body cavity and the intensified catabolism which results from different pathophysiology of digestive system diseases and coronary arterial disease.
ARTICLE | doi:10.20944/preprints201703.0194.v1
Subject: Chemistry, Food Chemistry Keywords: aromatic plants; HPLC; antioxidant capacity; DPPH; Rancimat test
Online: 27 March 2017 (09:57:43 CEST)
The antioxidant properties and polyphenol content of some selected aromatic plants grown in Greece were studied. Plants were refluxed with 60% methanol after acid hydrolysis. The phenolic substances were quantified by HPLC-DAD. The antioxidant capacity of the extracts was determined with the Rancimat test using sunflower oil as substrate. Free radical scavenging activity was measured using the stable free radical 1, 1-diphenyl-2-picrylhydrazyl (DPPH). Results were compared with standard BHT and ascorbic acid. Total phenol concentration of the extracts was estimated with Folin-Ciocalteu reagent using gallic acid as standard.
COMMUNICATION | doi:10.20944/preprints201610.0106.v1
Subject: Chemistry, Analytical Chemistry Keywords: vanillyl butyl ether; HPLC; method validation; cosmetic product
Online: 25 October 2016 (09:43:18 CEST)
A specific HPLC method has been developed and validated for the determination of vanillyl butyl ether in cosmetic products. The extraction procedure with an isopropanol water 1:1 mixture is described. The method uses a RP-C-18 column with isocratic elution and a UV detector. The mobile phase consists of a mixture of acetonitrile and buffer (Na2HPO4 20mM in water) (30:70 v/v) with a variable flow rate. The method was validated with respect to accuracy, precision (repeatability and reproducibility), specificity and linearity. The procedure described here is simple, selective and reliable for routine quality control analysis and stability tests of commercially available cosmetic products.
ARTICLE | doi:10.20944/preprints202211.0577.v1
Subject: Materials Science, General Materials Science Keywords: Recombinant Human Erythropoietin; Stability-indicating; Reverse phase; HPLC-UV
Online: 30 November 2022 (14:14:51 CET)
An HPLC method for indicating stability was developed, created, and confirmed for the quantification measurement of recombinant human erythropoietin in large quantities as well as dosage forms. An isocratic separation was accomplished using a Thermo Biobasic C18 (250 mm 4.6 mm i.d., 300Ao, 5 m) column with a flow rate of 1.0 mL min-1 as well as a UV detector to monitor the eluate at 278 nm. Acetonitrile, 0.05 mM potassium dihydrogen phosphate (80:20 v/v), and orthophosphoric acid adjusted to 4.0 made up the mobile phase. The drug was exposed to oxidative stress, hydrolysis, and photodegradation to simulate stress conditionsRecombinant Human Erythropoietin, the parent compound, was eluted at roughly 6.675 minutes, as well as all byproducts have been entirely disconnected inside an overall analytical run time of about 15 minutes. To identify quantification limits of 0.05 and 0.2 g mL-1, respectively, the method was linear over a concentration range of 1-6 g mL-1 (r = 0.9989). Recombinant Human Erythropoietin can be measured accurately, selectively, sensitively, and precisely using this method both in dosage form and in bulk. Stress-induced degradation products did not interact with the identification of Recombinant Human Erythropoietin, indicating that the assay is stable.
ARTICLE | doi:10.20944/preprints201906.0308.v1
Subject: Life Sciences, Biochemistry Keywords: chrysanthemum; HPLC; phenolic compounds; principal component analysis; antioxidant capacity
Online: 30 June 2019 (08:55:38 CEST)
This study investigated the phenolic compounds of 15 Chrysanthemum morifolium Ramat cv. ‘Hangbaiju’, including 6 ‘Duoju’ and 9 ‘Taiju’ using high performance liquid chromatography. The antioxidant activities of these ‘Hangbaiju’ were estimated by DPPH, ABTS and FPAR assays. Results showed that a total of 14 phenolic compounds were detected in these flowers, including 3 mono-caffeoylquinic acids, 3 di-caffeoylquinic acids, 1 phenolic acid and 7 flavonoids. ‘Duoju’ and ‘Taiju’ possessed different concentration of phenolic compounds, and ‘Taiju’ exhibited higher caffeoylquinic acids and stronger antioxidant activities than ‘Duoju’. Caffeoylquinic acids showed a strong correlation with the antioxidant activities of the samples. Principal component analysis revealed an obvious separation between ‘Duoju’ and ‘Taiju’ using phenolic compounds as variables. Apigenin-7-O-glucoside, 3,5-di-O-caffeoylquinic acid, luteolin and acacetin were found to be the key phenolic compounds to differentiate ‘Duoju’ from ‘Taiju’.
ARTICLE | doi:10.20944/preprints201905.0319.v1
Subject: Life Sciences, Microbiology Keywords: cyanobacteria; protease inhibitors; digestive enzyme; daphnia; HPLC; UV/Vis
Online: 27 May 2019 (12:56:49 CEST)
Cyanobacterial mass developments in eutrophic ponds and lakes are a major concern for lake management, as many cyanobacteria produce a huge variety of toxic secondary metabolites, e.g. microcystins. The aim of this research was to culture a strain of the cyanobacterium Microcystis sp strain BM25, to observe its biomass production and to isolate and purify protease inhibitors from this cyanobacterial biomass. Different secondary metabolites were isolated following a standard bioassay-guideline. Isolation was performed, with an enzymatic protease assay as bioassay. High performance liquid chromatography was used to identify different fractions of secondary metabolite from the strain BM25. Moreover, protease homogenates were isolated from Daphnia magna in order to test the inhibitors against naturally occurring major digestive proteases trypsin and chymotrypsin. It was measured that 60% MeOH and the 80% MeOH C18-SPE fraction inhibits chymotrypsin activity 98% (6 nmol pNA min-1 mg-1) and 99 % (4 nmol pNA min-1 mg-1), respectively. In contrast, trypsin activity was not inhibited by methanolic extracts of this cyanobacterium strain.
ARTICLE | doi:10.20944/preprints201901.0290.v1
Subject: Chemistry, Analytical Chemistry Keywords: Fiore Sardo PDO; biogenic amines; sheep’s cheese; RP-HPLC
Online: 29 January 2019 (09:32:26 CET)
This contribution is aimed to measure for the first time the amount of biogenic amines (BAs) in one of the most ancient and traditional sheep cheese produced in Sardinia, Italy: the Protected Designation of Origin (PDO) Fiore Sardo. For doing this, an original RP-HPLC-DAD-UV method has been developed, completely validated in terms of LoD, LoQ, linearity, precision and trueness, and tested on 36 real Fiore Sardo PDO cheese samples produced by four different cheesemakers and marketed by four stores. The average total concentration of the eight BAs (i.e. tyramine, tryptamine, histidine, putrescine, cadaverine, 2-phenylethylamine, spermine and spermidine) measured in Fiore Sardo cheese was 700 mg/kg, with a range between 170 mg/kg and 1100 mg/kg. A great variability in the total amount of BAs has been evidenced among the Fiore Sardo marketed in the four stores as well as for the cheeses purchased in different times in the same store. Tyramine (350 mg/kg), putrescine (150 mg/kg), histamine (80 mg/kg) and cadaverine (30 mg/kg) are the most abundant BAs found in this matrix. Among many factors concurring, the dominant microflora of Fiore Sardo PDO is likely the principal cause of the qualitative and quantitative distribution of BAs in this matrix. Finally, the total amount of BAs found in Fiore Sardo PDO is not able to cause any situation of health alert for consumers.
ARTICLE | doi:10.20944/preprints201810.0037.v1
Subject: Biology, Other Keywords: Knufia petricola A95, HPLC analysis, carotenoids, black yeasts, didehydrolycopene
Online: 2 October 2018 (22:39:22 CEST)
Black yeasts are a highly specified group of fungi, which are characterized by a high resistance against stress factors. There are several factors enabling the cells to survive harsh environmental conditions. One aspect is the pigmentation, besides the melanin black yeasts often display a highly diverse carotenoid spectrum. Determination and characterization of carotenoids depend on an efficient extraction and separation, therefore especially for black yeast, characterized by thick cell walls specific protocols are needed to ensure analyses regarding stress responses in these fungi. Here we present both, a method to extract and analyze carotenoids and the unusual carotenoid composition of the black yeast Knufia petriola A95. Mechanical treatment combined with an acetonitrile extraction gave us very good extraction rates with a high reproducibility. The presented extraction and elution protocol allows the separation of the main carotenoids (7) in K. petricola A95 and should be suitable for the detection of additional carotenoids in other species. K. petricola A95 displays an unusual carotenoid composition, with mainly didehydrolycopene, torulene and lycopene. The pigment composition varied in dependency to oxidative stress but remained relatively constant if the cells were cultivated under low temperature. Black yeasts are a promising source for carotenoid production and other substances. To unravel the potential of these fungi new methods and studies are needed. The established protocol allows the determination carotenoid composition in black yeasts. Oxidative stress results in an adaptation in pigment composition in K. petricola A95. Future experiments have to be carried out to determine if didehydrolycopene functions as a protective agent itself or if it serves as a precursor for antioxidative pigments like torulene and torularhodin, which could be produced after induction under stress conditions.
ARTICLE | doi:10.20944/preprints202108.0096.v1
Subject: Chemistry, Food Chemistry Keywords: Qinling mountains; Wild Chinese prickly ashes; HPLC fingerprint; Resource evaluation.
Online: 3 August 2021 (15:55:32 CEST)
Wild Chinese prickly ash with elevated antioxidants is a valuable genetic resource for Zanthoxylum bungeanum Maxim improvement. There are rich wild germplasm resources in the Qinling Mountains. In a study with wild germplasm resources from different altitudes and six cultivated varieties, the phenolic and flavonoid compounds were analyzed by high performance liquid chromatography (HPLC). The chromatograms of them were basically the same, although their chemical composition content was greatly different. The thirty samples were divided into three categories through the hierarchical clustering analysis. And catechin, hyperoside and quercitrin were considered to be key compound for the quality evaluation, by contrast, the wild samples with an altitude of 2300±50 m (Ⅳ group) had the highest content of key compounds, and showed stronger antioxidant activity and antibacterial ability, indicating that these wild samples could be used as an excellent breeding resource. This is the first time to evaluate the quality of wild Chinese prickly ash in different altitude areas of Qinling Mountains. These excellent wild germplasm resources provided substantial potential accessions for use directly in Chinese prickly ash breeding programs.
ARTICLE | doi:10.20944/preprints202103.0652.v1
Subject: Chemistry, 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.
ARTICLE | doi:10.20944/preprints201910.0073.v1
Subject: Biology, Agricultural Sciences & Agronomy Keywords: leds; elicitor; gynura procumbens; callus; hplc; lc-ms; cyanidin-monoglucosides
Online: 7 October 2019 (12:30:26 CEST)
Conventional fluorescent lamps used in tissue culture are costly light sources showing excessive wavelength emission-bandwidth that must be replaced by alternative, less costly and much lower power-consuming energy sources. The use of Light-Emitting Diodes (LEDs) is the best option due to their potential role as elicitors of secondary metabolite production in many plant models. Gynura procumbens(G. procumbens) is widely used for treating various diseases. Here, leaf explants were cultivated in MS medium supplemented with 0.5 mg/L of NAA and 2.0 mg/L of BAP for 30 days under white, blue, and red LEDs. Secondary metabolites were analyzed by HPLC and LC-MS. Blue LEDs elicited the highest antioxidant activity, total flavonoid, and phenolic content. Furthermore, the content of cyanidin-monoglucosides increased significantly increased under blue light.
ARTICLE | doi:10.20944/preprints201908.0263.v1
Subject: Chemistry, Physical Chemistry Keywords: 3-MBA; gold clusters; ESI-MS; HPLC-MS; bidentate binding
Online: 26 August 2019 (11:08:56 CEST)
Gold clusters protected by 3-MBA ligands (MBA = mercaptobenzoic acid, -SPhCO2H) have attracted recent interest for their unusual structures and advantageous ligand-exchange and bioconjugation properties. Azubel et al. first determined the core structure of an Au68-complex, which was estimated to have 32 ligands (3-MBA groups). To explain the exceptional structure-composition and reaction properties of this complex, and its larger homologs, Tero et al. proposed a “dynamic stabilization” via carboxyl O-H--Au interactions. Herein, we report the first results of an integrated LC/MS analysis of unfractionated samples of gold / 3-MBA clusters, spanning the narrow size range 13.4 to 18.1 kDa. Using high-throughput procedures adapted from bio-macromolecule analyses, we show that integrated capillary HPLC-ESI-MS, based upon aqueous-methanol mobile phases and ion-pairing reverse-phase chromatography, can separate several major components from the nanoclusters mixture that may be difficult to resolve by standard native gel electrophoresis due to their similar size and charge. For each component, one obtains a well-resolved mass spectrum, nearly free of adducts or signs of fragmentation. A consistent set of molecular mass determinations is calculated from detected charge-states tunable from 3- (or lower), to 2+ (or higher). One thus arrives at a series of new compositions (n, p) specific to the Au/3-MBA system. The smallest major component is assigned to the previously unknown (48, 26); the largest one is evidently (67, 30), vs. the anticipated (68, 32). Various explanations for this discrepancy are considered. A prospective is given for the several members of this novel series, along with a summary of the advantages and present limitations of the micro-scale integrated LC/MS approach to characterize such metallic-core macro-molecules, and their derivatives.
ARTICLE | doi:10.20944/preprints201805.0175.v1
Subject: Medicine & Pharmacology, Pharmacology & Toxicology Keywords: Tamarix nilotica; Tamaricaceae; polyphenols; HPLC/HRESI/MS/MS; antifibrotic activity
Online: 11 May 2018 (05:18:58 CEST)
Tamarix nilotica (Ehrenb.) Bunge (Tamaricaceae), an indigenous plant to the Middle East region, is well-known as a medicinal plant for treating many human ailments. The current study aimed at exploring the polyphenols profile of T.nilotica alcohol soluble fraction of aqueous extract, assessing its in-vivo antifibrotic activity and the possible underlying mechanism, to unravel the impact of quantitative difference of sulphated polyphenols content on the antifibrotic activity of T.nilotca grown in two different habitats. Polyphenols profiling of T. nilotica extracts was performed using HPLC-HRESI-QTOF-MS-MS. The major polyphenol components included sulphated flavonoids, phenolic acids and free aglycones. The antifibrotic activity was evaluated through carbon tetrachloride-induced liver fibrosis in rats. Biochemical evaluations revealed that both fractions ameliorated the increased levels of hepatic aminotransferases, lipid peroxidation, hydroxyproline, α-smooth muscle actin (α-SMA), tumor necrosis factor-α (TNF-α), cyclooxygenase-2 (COX-2) and nuclear factor kappa B (NF-κB). Moreover, both fractions reduced catalase activity (CAT) and enhanced hepatic glutathione (GSH) content. Histopathological imaging undoubtedly confirmed such results. In conclusion, T. nilotica polyphenols rich fraction exhibited potential antifibrotic activity in rats. Significant alterations in GSH levels were recorded based on sulphated polyphenol metabolites content.
ARTICLE | doi:10.20944/preprints201705.0113.v1
Subject: Biology, Agricultural Sciences & Agronomy Keywords: Solanum nigrum; anthocyanins purification; HPLC-MS/MS; antioxidant capacity; SnMYB
Online: 15 May 2017 (17:31:53 CEST)
Solanum nigrum fruits have been conventionally available as a material of beverage due to its nutritional substances such as minerals, vitamins, amino acids, proteins, sugars, polyphenols and anthocyanins. Here has rarely reported on the characterizaton of the components and the regulatory mechanism of Anthocyanins in S. nigrum. In this study, we determined that the peel and flesh of S. nigrum fruits shared the similar HPLC profiles, but the different contents and total antioxidant activities for Anthocyanins. After an efficient purification method mainly including extraction with pH 1.0 distilled water and then desorption with pH 1.0 95% ethanol after a DM-130 resin adsorption step to obtain more pure anthocyanins extracts, the purity of anthocyanins extract from S. nigrum fruits reached to 56.1%. Moreover, eight anthocyanins from S. nigrum fruit were identified with HPLC-MS/MS for the first time. A typical R2R3-MYB transcription factor gene, SnMYB, was also cloned for the first time by RACE-PCR from S. nigrum. Moreover, the contents of anthocyanins was shown a good correlation (r = 0.93) with the expression levels of SnMYB during the fruits developmental stages. Most significantly, SnMYB successfully produced high anthocyanins contents (1.03 mg/g) when SnMYB was transiently expressed in tobacco leaves. Taken together, S. nigrum fruits are a promising resource for anthocyanins extraction and SnMYB is an activator that positively regulates anthocyanins biosynthesis in S. nigrum.
ARTICLE | doi:10.20944/preprints202009.0055.v1
Subject: Life Sciences, Other Keywords: mortiño; Vaccinium floribundum; HPLC-MS/MS; anthocyanins; antioxidant; antimicrobial; toxicity; Zebrafish.
Online: 3 September 2020 (04:43:08 CEST)
Andean blueberries are wild berries grown and consumed in Ecuador which contain high values of bioactive compounds, mainly anthocyanins, with powerful antioxidant activity. The aim of this study was to evaluate the profile and contents of (poly)phenols and carotenoids in Andean blueberry by HPLC-DAD-MSn and determine a wide range of its biological activities. The antioxidant capacity of this fruit was evaluated in vitro by three different methods and in vivo using the zebrafish animal model, also the toxicity effect was determined by the zebrafish embryogenesis test. Besides, the antimicrobial activity and the capacity of Andean blueberry to produce hemagglutination in blood cells were evaluated. Finally, the bioaccessibility of (poly)phenols and related antioxidant capacity were determined in the different phases of an in vitro digestion. The global results indicated no toxicity of Andean blueberry, weakly bacteriostatic activity, and high contents of anthocyanins and antioxidant capacity, which were partially bioaccesible in vitro (~ 50 % at the final intestinal step), contributing to the knowledge of its health benefits for consumers and its potential use in the food and pharmaceutical industry as functional ingredient.
ARTICLE | doi:10.20944/preprints201911.0257.v1
Subject: Chemistry, Other Keywords: Papaver somniferum L.; lipoxygenase; purification; lipoxygenase products; positional specificity; HPLC analysis
Online: 22 November 2019 (07:20:28 CET)
Opium poppy (Papaver somniferum L.) is an ancient medicinal plant producing pharmaceutically important benzylisoquinoline alkaloids. In the present work we focused on the study of enzyme lipoxygenase (LOX, EC 126.96.36.199) from opium poppy cultures. LOX is involved in lipid peroxidation and lipoxygenase oxidation products of polyunsaturated fatty acids have a significant role in regulation of growth, development and plant defence responses to biotic or abiotic stress. The purpose of this study was to isolate and characterize LOX enzyme from opium poppy callus cultures. LOX was purified by ammonium sulphate precipitation followed by hydrophobic chromatography using Phenyl-Sepharose CL-4B and hydroxyapatite chromatography using HA Ultrogel sorbent. SDS-PAGE analysis and immunoblotting revealed that LOX from opium poppy cultures was a single monomeric protein showing the relative molecular weight of 83 kDa. To investigate the positional specificity of the LOX reaction, purified LOX was incubated with linoleic acid and the products were analysed by high-performance liquid chromatography. LOX converted linoleic acid primarily to 13-hydroperoxy-(9Z,11E)-octadecadienoic acids (78%) and to a lesser extent to 9-hydroperoxy-(10E,12Z)-octadecadienoic acids (22%). Characterization of LOX from opium poppy cultures provided valuable information in understanding of LOX involvement in regulation of signalling pathways leading to biosynthesis of secondary metabolites with significant biological activity.
ARTICLE | doi:10.20944/preprints201904.0156.v1
Subject: Life Sciences, Other Keywords: quercetin; eugenol; organic compounds; rumen; environment; HPLC-DAD; polyphenols-containing plants
Online: 13 April 2019 (05:23:35 CEST)
This study had the objective to evaluate the effect of Piper betle L. powder (PP) at 5 different doses in substrate incubated by sunflower oil as secondary function of PUFA using in vitro gas production technique. The treatments of this study were run as a 2X5 factorial arrangement in a completely randomised design using the PROC GLM procedure of SAS 9.4: (1) control (S1) without supplementation of PP; (2) 15 mg PP (S2); (3) 30 mg PP (S3); (4) 45 mg PP (S4); and (5) 60 mg PP (S5), while sunflower oil was supplemented in all treatments: low 15 mg/incubation and high 30 mg/incubation. A 500 mg of TMR (hay: concentrate, 50:50) was assigned to basal substrate. The PP containing 1.84 mg/g DM quercetin and 1.00 mg/g DM eugenol altered rumen fermentation without change pH (p < 0.001) and methane production was lesser (p < 0.001) about -30% and -25% for DM and OM measurement, respectively. Gas kinetic, degradability, and ammonia level was significantly affected by supplementing PP (p < 0.01). Overall, this study suggested quercetin and eugenol deriving from PP acted three major accelerations: assembled carbon dioxide, behaved antimicrobial role and performed the balance water molecules in the rumen kinetic. This study suggests that PP promotes changing in vitro rumen fermentation and diminishing methane production within recommended doses, 0.1-15 mg/incubation in DM.
ARTICLE | doi:10.20944/preprints201807.0552.v1
Subject: Chemistry, Medicinal Chemistry Keywords: Hedgehog signaling; Veratrum californicum; cyclopamine; HPLC-MS; Shh-Light II cells
Online: 28 July 2018 (23:25:31 CEST)
Veratrum californicum is a rich source of steroidal alkaloids such as cyclopamine, a known inhibitor of the Hedgehog (Hh) signaling pathway. Here we provide a detailed analysis of the alkaloid composition of V. californicum by plant part through quantitative analysis of cyclopamine, veratramine, muldamine and isorubijervine in the leaf, stem and root/rhizome of the plant. To determine if additional alkaloids in the extracts contribute to Hh signaling inhibition, we replicated the concentrations of these alkaloids observed in extracts using commercially available standards and compared the inhibitory potential of the extracts to alkaloid standard mixtures using Shh-Light II cells. Alkaloid combinations enhanced Hh signaling pathway antagonism compared to cyclopamine alone, and significant differences were observed in the Hh pathway inhibition between the stem and root/rhizome extracts and their corresponding alkaloid standard mixtures, indicating that additional alkaloids present in these extracts contribute to Hh signaling inhibition.
REVIEW | doi:10.20944/preprints202108.0383.v1
Subject: Chemistry, Analytical Chemistry Keywords: Bacterial carotenoids; Cell disruption; HPLC separation; MS analysis; Food and textile applications
Online: 18 August 2021 (14:09:35 CEST)
Natural carotenoids are secondary metabolites that exhibit antioxidant, anti-inflammatory and anti-cancer properties. These types of compounds are in high demand by pharmaceutical, cosmetic, textile and food industries, leading to the search for new natural sources of carotenoids. In recent years, the production of carotenoids from bacteria has become of great interest for industrial applications. In addition to carotenoids with C40-skeletons, some bacteria have the ability to synthesize characteristic carotenoids with C30-skeletons. In this regard, a great variety of methodologies for the extraction and identification of bacterial carotenoids has been reported and this is the first review that condenses much of this information. To understand the diversity of these carotenoids, we present their biosynthetic origin in order to focus on the methodologies employed in their extraction and characterization. Special emphasis has been made on high-performance liquid chromatography-mass spectrometry (HPLC-MS) for the analysis and identification of bacterial carotenoids. We end up this review showing their potential commercial use of bacterial carotenoids. This review is proposed as a guide for the identification of these metabolites, which are frequently reported in new bacteria strains.
ARTICLE | doi:10.20944/preprints202010.0475.v1
Subject: Life Sciences, Biochemistry Keywords: Rosmarinus officinalis; Salvia officinalis; natural antioxidant; antibacterial activity; total phenolic compounds; HPLC; TBARS.
Online: 23 October 2020 (09:48:36 CEST)
This study aimed to evaluate the antioxidant activities (AA) of lyophilized rosemary extract and lyophilized sage extract and their effects on the oxidative stability of poultry pátê. For this purpose, four poultry pátê formulations with rosemary, sage, sodium erythorbate, and a control (without antioxidants) were produced. The rosemary and sage were characterized according to total phenolic compounds (TPC), and AA by several methods. The poultry pátês stored at 4°C were evaluated by the lipid oxidation. High concentrations of TPC were detected in rosemary extract and sage extract (46.48 and 41.61 mg GAE/g: Gallic acid equivalent respectively). The AA of rosemary and sage extracts by free radical-scavenging were 4745.72 and 2462.82 µmol Trolox/g, respectively. The high concentration of catechin, rutin, myricetin and p-coumaric acids in these extracts may be responsible for the strong inhibitory action against food pathogens. Besides these compounds can be responsible for the best performance in inhibiting lipid oxidation in poultry pátês during the storage. This study suggests that rosemary and sage extracts may be used as a natural antioxidant in meat products.
ARTICLE | doi:10.20944/preprints201901.0041.v1
Subject: Biology, Physiology Keywords: nonalcoholic fatty liver disease; high fat-sucrose diet; metabolomics; HPLC-QTOF-MS; quercetin
Online: 4 January 2019 (14:04:13 CET)
As metabolomics is widely used in the study of disease mechanisms, more and more studies have found that metabolites play an important role in the occurrence of diseases. The aim of this study is to investigate the effects and mechanisms of quercetin in high-fat-sucrose diet (HFD)-induced nonalcoholic fatty liver disease (NAFLD) development using nontargeted metabolomics. A rat model of NAFLD was established by feeding with a HFD for 30 and 50 days. Results indicated quercetin exhibited hepatoprotective activity in HFD-induced NAFLD rats in 30 days by regulating fatty acids related metabolites (adrenic acid, etc.), inflammation related metabolites (arachidonic acid, etc.), oxidative stress related metabolites (2-hydroxybutyric acid) and other differential metabolites (citric acid, etc.). However, quercetin couldn’t improve NAFLD in 50 days maybe it couldn’t reverse the inflammation condition induced by long-term high-fat diet. These data indicate that dietary quercetin may be beneficial to NAFLD at early stages. Furthermore, combining metabolomics and experimental approaches opens up avenues of effects and mechanisms of drugs for complex diseases.
ARTICLE | doi:10.20944/preprints202103.0675.v1
Subject: Biology, Anatomy & Morphology Keywords: Fruit ripening; gingerglycolipid A; HPLC-HRMS; melatonin; nitric oxide; phytosphingosin; quercetin; transcriptomics; L-tryptophan
Online: 26 March 2021 (15:44:51 CET)
Plant species are precursors of a wide variety of secondary metabolites that, besides having useful activity for themselves, can also be used by humans for their consumption and economic benefit. Pepper (Capsicum annuum L.) fruit is not only a common food and spice source, but it also stands out for containing high amounts of antioxidants (such as vitamins C and A), polyphenols and capsaicinoids. Particular attention has been paid to capsaicin, whose anti-inflammatory, antiproliferative and analgesic activities, have been proven. Due to the potential interest in pepper metabolites for human use, in this project, we carried out an investigation to identify new bioactive compounds of this crop is carried out. To achieve this, we developed a metabolomic approach, using an HPLC (high-performance liquid chromatography) separative technique coupled to metabolite identification by high resolution mass spectrometry (HRMS). After chromatographic analysis and data processing against metabolic databases, 12 differential bioactive compounds were identified in sweet pepper fruits, including quercetin and its derivatives, L-tryptophan, phytosphingosin, FAD, gingerglycolipid A, tetrahydropentoxylin, blumenol C glucoside, colnelenic acid and capsoside A. The abundance of these metabolites varied depending on the ripening stage of the fruits, either immature green or ripe red. We also studied the variation of these 12 metabolites upon treatment with exogenous nitric oxide (NO), a free radical gas involved in a good number of physiological processes in higher plants such as germination, growth, flowering, senescence, and fruit ripening, among others. Overall, it was found that the content of the analysed metabolites was modulated by the ripening stage and by the presence of NO. The metabolic pattern followed by quercetin and its derivatives, as a consequence of the ripening stage and NO treatment, was also corroborated by transcriptomic analysis of genes involved in the synthesis of these compounds. This opens new research windows on the pepper fruit’s bioactive compounds with nutraceutical potentiality, where biotechnological strategies can be applied for optimizing the level of these beneficial compounds.
ARTICLE | doi:10.20944/preprints202109.0071.v1
Subject: Medicine & Pharmacology, Pharmacology & Toxicology Keywords: lysophospholipids; lysophosphatidic acids; cardiovascular diseases; HPLC-MS/MS; rodent models; pulmonary hypertension; chronic heart failure; hypertension
Online: 3 September 2021 (15:19:54 CEST)
Cardiovascular diseases (CVD) are the leading cause of premature death and disability in humans. Increasing data suggest that CVD is closely related to lipid metabolism and signaling. This study aimed to assess whether circulating lysophospholipids (LPL), lysophosphatidic acids (LPA) and monoacylglycerols (MAG) may be considered as biomarkers of CVD. For this objective, the evolution of the plasma levels of 22 compounds (13 LPL, 6 LPA and 3 MAG) was monitored by liquid chromatography coupled with tandem mass spectrometry (HPLC/MS²) in different rat models of CVD, i.e. angiotensin-II-induced hypertension (HTN), ischemic chronic heart failure (CHF) and sugen/hypoxia(SuHx)-induced pulmonary hypertension (PH). On one hand, there was modest changes on the monitored compounds in HTN (LPA 16:0, 18:1 and 20:4), LPC 16:1) and CHF (LPA 16:0, LPC 18:1 and LPE 16:0 and 18:0) models compared to control rats but these changes were no longer significant after correction for multiple testing. On the other hand, PH was associated with important changes in plasma LPA with a significant increase in the 16:0, 18:1, 18:2, 20:4 and 22:6 species. A deleterious impact of LPA was confirmed on isolated human pulmonary smooth muscle cells with an increase in their proliferation. This study demonstrates that circulating LPA species are increased in rats with PH and may contribute to the pathophysiology of this disease. Additional experiments are needed to assess whether the modulation of LPA signaling in PH may be of interest.
ARTICLE | doi:10.20944/preprints201906.0275.v1
Subject: Life Sciences, Molecular Biology Keywords: ketogenic diet; breast cancer; xenograft; untargeted metabolomics; HPLC-MS; reversed phase chromatography; hydrophilic interaction liquid chromatography
Online: 27 June 2019 (05:35:28 CEST)
Ketogenic diet (KD) is getting in the focus as auxiliary cancer therapy, since it provides sufficient energy supply for healthy cells, while impairing energy production in tumor cells underlying the Warburg effect. Thereby, it can assist in inhibiting tumor growth and simultaneously counteract cachexia, which is frequently observed in cancer patients under chemotherapy. In order to provide molecular evidence for the proposed synergistic inhibition of tumor growth, we applied untargeted quantitative metabolome analysis on a breast cancer xenograft mouse model. Healthy mice and such bearing breast cancer xenografts and receiving chemotherapy were compared after treatment with control diet and KD. Metabolomic profiling was performed on plasma samples, applying high-performance liquid chromatography coupled to tandem mass spectrometry. Statistical analysis revealed metabolic fingerprints comprising numerous significantly regulated features in the group of mice bearing breast cancer. This fingerprint disappeared after treatment with KD, resulting in recovery to the metabolic status observed in healthy mice receiving control diet. Moreover, amino acid metabolism as well as fatty acid transport were found to be affected by both, the tumor and the applied KD. Our results provide clear evidence of a significant molecular effect of KD in the context of tumor growth inhibition.
ARTICLE | doi:10.20944/preprints202209.0026.v1
Subject: Chemistry, Medicinal Chemistry Keywords: Bacopa procumbens HPLC characterization; effect of polyphenolic compounds; in vitro and in vivo skin wound; collagen organization
Online: 1 September 2022 (15:44:09 CEST)
Wounds represents a medical problem that contribute importantly to patient morbidity and to the healthcare costs in several pathologies. In Hidalgo, Mexico, Bacopa procumbens plant has been traditionally used for wound healing care for several generations; in vitro and in vivo experiments were design to evaluate the effects of bioactive compounds obtained from B. procumbens aquoethanolic extract and to determine the key pathways involved in wound regeneration. Bioactive compounds were characterized by HPLC- QTOF-MS and proliferation, migration, adhesion, and differentiation studies were done on NIH/3T3 fibroblasts. Polyphenolic compounds from Bacopa procumbens (PB) regulated proliferation and cell adhesion; enhanced migration reducing the artificial scratch area; and modulated cell differentiation. PB compounds were included in a hydrogel for topical administration on rat excision wound model. Histological, histochemical and mechanical analysis showed that PB treatment accelerates wound closure in at least 48 h; reduce inflammation, increasing cell proliferation and deposition and organization of collagen in earlier times. These changes resulted in the formation of a scar with better tensile properties. Immunohistochemistry and RT-PCR molecular analyses demonstrated that treatment induces: i) overexpression of transforming growth factor beta (TGF-β); and ii) the phosphorylation of Smad 2/3 and ERK1/2, suggesting the central role of some PB to enhance wound healing, modulating TGF-β activation.
ARTICLE | doi:10.20944/preprints201811.0548.v1
Subject: Chemistry, Food Chemistry Keywords: Persimmon, Diospyrus kaki Thunb., var. Rojo Brillante, astringent, carotenoids, carotenoid esters, HPLC-PDA-MS (APCI+), processing effects
Online: 22 November 2018 (14:26:40 CET)
Carotenoid and carotenoid esters profiles of peel, pulp and whole fruit tissues of astringent persimmon (Diospyrus kaki Thunb., var. Rojo Brillante) have been characterized in detail and quantified for the first time. Carotenoids were determined by HPLC-PDA-MS/MS (APCI+), using a reverse phase C30 column. A total of 38 carotenoids were identified and quantified, corresponding to 21 free carotenoids (13 xanthophylls and 8 hydrocarbon carotenes) and a total of 17 carotenoid esters. The qualitative profiles are very similar among tissues, differing only in the carotenoids concentration. The most important identified free xanthophylls were (all-E)-β-cryptoxanthin, (all-E)-antheraxanthin, (all-E)-lutein, (all-E)-zeaxanthin and (all-E)-violaxanthin . Hydrocarbon carotenoids found were (all-E)-β-carotene, (all-E)-α-carotene, (9Z)-β-carotene, (13Z)-β-carotene, (9Z)-α-carotene, and lycopene. The most abundant carotenoid esters were (all-E)-lutein-3-O-palmitate, (all-E)-zeaxanthin myristate, (all-E)-zeaxanthin palmitate and (all-E)-cryptoxanthin laurate. Processing by high pressures produced no regular effect on persimmon carotenoids and pasteurization affected negatively the content of all carotenoids from all studied persimmon tissues. This work will contribute to the development of scientific research about the bioaccessibity and bioavailabity of each individual free or esterified persimmon carotenoids in order to a better understanding of the carotenoid compounds impact in human health.
ARTICLE | doi:10.20944/preprints202102.0211.v1
Subject: Chemistry, Analytical Chemistry Keywords: microplastics; marine sediment; pet; nylon 6; nylon 6,6; reversed-phase HPLC; polyolefin; polystyrene; Pyr-GC/MS; polymer degradation
Online: 8 February 2021 (13:13:37 CET)
Microplastics (MPs) quantification in benthic marine sediments is typically performed by time-consuming and moderately accurate mechanical separation and microscopy detection. In this paper we describe the results of our innovative Polymer Identification and Specific Analysis (PISA) of microplastic total mass, previously tested on either less complex sandy beach sediment or less demanding (because of the high MPs content) wastewater treatment plant sludges, applied to the analysis of benthic sediments from a sublittoral area north-west of Leghorn (Tuscany, Italy). Samples were collected from two shallow sites characterized by coarse debris in a mixed seabed of Posidonia oceanica, and by a very fine silty-organogenic sediment, respectively. After sieving at <2 mm the sediment was sequentially extracted with selective organic solvents and the two polymer classes polystyrene (PS) and polyolefins (PE and PP) were quantified by pyrolysis-GC/MS. A contamination in the 8-65 ppm range by PS could be accurately detected. Acid hydrolysis on the extracted residue to achieve total depolymerization of all natural and synthetic polyamides, tagging of all aminated species in the hydrolyzate with a fluorophore, and reversed-phase HPLC (RP-HPLC) analysis, allowed to quantify within the 137-1523 ppm range the individual mass of contaminating Nylon 6 and Nylon 6,6, based on the detected amounts of the respective monomeric amines 6-aminohexanoic acid (AHA) and hexanediamine (HMDA). Finally, alkaline hydrolysis of the residue from acid hydrolysis followed by RP-HPLC analysis of the purified hydrolysate showed contamination by polyethylene terephthalate (PET) in the 12.1-2.7 ppm range, based on the content of its comonomer, terephthalic acid.
ARTICLE | doi:10.20944/preprints201804.0309.v1
Subject: Chemistry, Analytical Chemistry Keywords: phenyltin derivatives; tetraphenyltin; triphenyltin chloride; triphenyltin acetate; triphenyltin hydroxide; fabric phase sorptive extraction (FPSE), high performance liquid chromatography (HPLC)
Online: 24 April 2018 (07:45:23 CEST)
This paper reports a novel fabric phase sorptive extraction-high performance liquid chromatography-ultra violet detection (FPSE-HPLC-UV) method for the simultaneous extraction and analysis of four phenyltin derivatives that include triphenyltin hydroxide, triphenyltin acetate, triphenyltin chloride and tetraphenyltin in environmental water (agricultural waste water and municipal waste water) and canned food samples. The selected analytes were well resolved by Waters Nova pack C18 column (3.9 x 150 mm, 4 µm particle size) in isocratic elution mode within 15 minutes. The new microextraction media has been analytically evaluated using phenyltin derivatives as model compounds. The factors affecting the extraction efficiency of FPSE have been evaluated and the optimum extraction conditions were determined. Under these optimum conditions, the limits of detection (LODs) for sol-gel C18 coated fabric phase sorptive extraction (FPSE) media in combination with HPLC-UV for the analysis of the phenyltin derivatives were in the range of 10-100 ng/mL with high precision (low relative standard deviation) at 10 ng/mL concentration with good absolute recoveries. To the best of our knowledge, this is the first FPSE extraction procedure applied to environmental water and canned food samples for the simultaneous determination of phenyltin derivatives and could be readily adopted as a rapid and robust green analytical tool for routine environmental and food analytical laboratories.
ARTICLE | doi:10.20944/preprints201804.0073.v1
Subject: Chemistry, Food Chemistry Keywords: Rossa da inverno sel. Rojo Duro onion cultivar; geographical origin; amino acids content; HPLC analysis; statistical evaluations; food traceability
Online: 6 April 2018 (09:04:47 CEST)
In the frame of a broader project, we were interested at comparing the amino acid profile in a specific variety of onion, Rossa da inverno sel. Rojo Duro, produced in two different Italian sites: Cannara (Umbria region) and Imola (Emilia Romagna region). In both places, onions were cultivated and harvested in the same way, and irrigated by water sprinkler method. A further group of Cannara onions, growth by microirrigation, was also evaluated. After the extraction of free amino acid mixture from onion samples, an ion-pairing RP-HPLC method allowed the separation and the evaporative light scattering detection of almost all underivatized proteinogenic amino acids. However, only the peaks corresponding to Leu, Phe, Trp, were present in all the investigated samples and unaffected from matrix interfering peaks. The application of the beeswarm/box plots with the ANOVA/TukeyHSD statistical approach revealed a content of Leu and Phe markedly influenced by the geographical origin of the onions, while not by the irrigation procedure. The developed HPLC method was validated in terms of specificity, linearity, LOD and LOQ, accuracy and precision, before the quantitative assay of Leu, Phe and Trp in the onion samples. Although further studies are necessary, these preliminary findings can represent a good starting point for considering the quantity of specific amino acids in the Rossa da inverno sel. Rojo Duro variety as a fingerprint of its geographical origin. In principle, the developed approach might be applied to other onion varieties, thus contributing to their characterization and traceability, also contributing to limit commercial frauds.
ARTICLE | doi:10.20944/preprints202103.0298.v1
Subject: Life Sciences, Biochemistry Keywords: Affinity chromatography; matrix; solid support; resin; support materials; glass filter; glass frit; high-pressure; HPLC; FPLC; antibodies; immunoglobulins; purification; downstream processing; protein purification; preparative; analytical; separation; clean-up; automation
Online: 11 March 2021 (08:37:01 CET)
A novel stationary phase for affinity separations is presented. This material is based on sintered borosilicate glass readily available as semi-finished filter plates with defined porosity and surface area. The material shows fast binding kinetics and excellent long-term stability under real application conditions due to lacking macropores and high mechanical rigidity. The glass surface can be easily modified with standard organosilane chemistry to immobilize selective binders or other molecules used for biointeraction. In this paper, the manufacturing of the columns and their respective column holders by 3D printing is shown in detail. The model system protein A/IgG was chosen as an example to examine the properties of such monolithic columns under realistic application conditions. Several specifications, such as (dynamic) IgG capacity, pressure stability, long-term performance, productivity, non-specific binding, and peak shape, are presented. It could be shown that due to the very high separation speed, 250 mg antibody per hour and column can be collected, which surpasses the productivity of most standard columns of the same size. The total IgG capacity of the shown columns is around 4 mg (5.5 mg/mL), which is sufficient for most tasks in research laboratories. The cycle time of an IgG separation can be less than 1 minute. Due to the glass material's excellent pressure resistance, these columns are compatible with standard HPLC systems. This is usually not the case with standard affinity columns, limited to manual use or application in low-pressure systems. The use of a standard HPLC system also improves the ability for automation, which enables the purification of hundreds of cell supernatants in one day. The sharp peak shape of the elution leads to an enrichment effect, which might increase the concentration of IgG by a factor of 3. The final concentration of IgG can be around 7.5 mg/mL without the need for an additional nanofiltration step. The purity of the IgG was > 95% in one step and nearly 99% with a second polishing run.