Determination Of Antioxidant Capacity Research Articles

Total Phenolic and Flavonoid Content, and Antioxidant Capacity of Red Ginger (Zingiber officinale var. Rubrum) Ethanolic Extract and Fraction

Determination of total phenolic, total flavonoid, and antioxidant capacity of ethanolic extract and fractions from red ginger (Zingiber officinale var. Rubrum) has been done. Red gingers contain the highest oleoresins among other ginger varieties. Oleoresins are component that had the most responsibility for pharmacological effect of red ginger, one of them is as antioxidant. Phenolic and flavonoid are highly contributing to the antioxidant effect of red ginger. The aim of this research is to determine the antioxidant capacity of extract and fractions of red ginger, and to investigate the correlation between antioxidant capacity with both total phenolic and total flavonoid. Ethanolic extracts are fractinationed with n-hexane, chloroform, ethyl acetate, n-butanol, and methanol solvent. Antioxidant capacity, total phenolic, and total flavonoid of all the samples are measured. Highest antioxidant capacity, total phenolic, and total flavonoid obtained from ethyl acetate fraction with TEAC 2143.9 ± 0.9 µmol/g (CUPRAC) and 4526.4 ± 3.0 (DPPH), GAE 229.9 ± 1.3 mg/g, and QE 46,6 ± 1,8 mg/g. One way ANOVA and post hoc analysis show significant result with p value <0,01. Pearson correlation shows high positive correlation . Determination of total phenolic, total flavonoid, antioxidant capacity from ethanolic extract and fractions of red ginger (Zingiber officinale var. Rubrum) has been done. Red ginger contain the highest oleoresins among other ginger varieties. Oleoresins are component that had the most responsibility for pharmacological effect of red ginger, one of them is as antioxidant. Phenolic and flavonoid are highly contribute to the antioxidant effect of red ginger. The aim of this research is to determine the antioxidant capacity of extract and fractions of red ginger, and to investigate the correlation between antioxidant capacity with both total phenolic and total flavonoid. Ethanolic extracts are fractinationed with n-hexane, chloroform, ethyl acetate, n-butanol, and methanol solvent. Antioxidant capacity, total phenolic, and total flavonoid of all the samples are measured. Highest antioxidant capacity, total phenolic, and total flavonoid obtained from ethyl acetate fraction with TEAC 2143,893 ± 0,890 µmol/g, GAE 229,878 ± 1,330 mg/g, and QE 46,564 ± 1,804 mg/g. One way ANOVA and post hoc analysis show significant result with p value <0,01. Pearson correlation shows high positive correlation.

Protective effect of chloroform extract of Stereospermum chelonoides bark against amyloid beta42 induced cell death in SH-SY5Y cells and against inflammation in Swiss albino mice.

Background This study was designed to evaluate the free radical scavenging property of chloroform extract of the bark of Stereospermum chelonoides (SCBC) and to investigate its potential in Alzheimer's disease and inflammation, two oxidative stress related disorders. Methods Preliminary phytochemical analysis and in vitro antioxidant potential of SCBC were evaluated using 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay, ferric reducing antioxidant power (FRAP) assay, cupric reducing antioxidant capacity (CUPRAC) and total antioxidant capacity determination assay. Total phenol and total flavonoid contents were also determined. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) based cytotoxicity and cyto-protective assays were performed on human neuroblastoma SH-SY5Y cells. Thioflavin-T assay and caspase activation measurement assay were carried out to elucidate the mechanism of cytoprotection of SCBC observed here. In vivo anti-inflammatory potential was measured using croton oil and xylene induced ear edema tests. Results Phytochemical screening of SCBC revealed the presence of various phytoconstituents. Dose-dependent in vitro antioxidant activity was observed. The extract was enriched in flavonoids and polyphenolic compounds too. SCBC was found to inhibit amyloid-β peptide 1-42 (Aβ42) induced cell death in a dose-dependent manner. Encouraged by the cyto-protective effect, its effects on Aβ42 fibrillogenesis and caspase-3 activated apoptosis were observed. SCBC significantly slowed down the Aβ42 fibrillogenesis and caspase-3 activation in a concentration-dependent manner indicating its probable mechanism of rendering cyto-protection. SCBC has been able to reduce inflammation significantly in croton oil induced ear edema in both doses. Conclusions Thus, this study could form the basis for further study for the potential use of SCBC in oxidative stress associated cell death and inflammation.

Simple scanometric assay based on DPPH immobilized on pharmaceutical blister for determination of antioxidant capacity in the herbal extracts

Simple scanometric assay based on DPPH immobilized on pharmaceutical blister for determination of antioxidant capacity in the herbal extracts

Taflan (Prunus laurocerasus L) Yaprağı ve Çekirdeğinin Ferrotiyosiyanat Metoduyla Total Antioksidan Kapasitesinin Belirlenmesi

Taflan veya karayemiş olarak da bilinen Prunus laurocerasus Karadeniz bölgesinde yaygın olarak bulunmaktadır. Ordu ilinden 2016 Ağustos ayında yaprakları ve meyveleri toplanan P. laurocerasus bitkisinin toplam antioksidan kapasitesini belirlemek amacıyla bu çalışma yapılmıştır. Toplanan örnekler yaprak ve meyvenin çekirdeği olmak üzere ayrılmış, metanol ve etanol çözücüleri içerisinde çözülerek ayrı ekstraktlar elde edilmiştir. Toplam antioksidan kapasitesi ferrotiyosiyanat metoduna göre hazırlanan ekstraktlarda 12 saatte bir olmak üzere spektrofotometrik olarak ölçülmüştür. En yüksek inhibisyon yüzdesi metanol ekstraktları için 84. saatte gerçekleşmiştir. P. laurocerasus metanol ekstraktının yaprağı için yüzde inhibisyon değeri 66,97, çekirdeği için 67,10 olarak belirlenmiştir. Yaprak ve çekirdeklerinin etanol ekstraktları ise 48. saatte en yüksek yüzde inhibisyon göstererek 94,67 ve 91,06 değerlerine ulaşmışlardır. Butilen hidroksi toluene (BHT) ve troloksun yüzde inhibisyon değerleri 48. Saatte 39,85 ve 43,81 olarak hesaplanmıştır. P. laurocerasus yaprağı ve çekirdeğinin standart antioksidanlara göre yüksek antioksidan aktivite gösterdiği tespit edilmiştir. Ayrıca etanol ekstraktının da metanol ekstraktına göre daha yüksek antioksidan aktivite verdiği görülmüştür. P. laurocerasus çekirdeğinin ise yaprağına göre daha yüksek antioksidan kapasiteye sahip olduğu söylenebilir.

Determination of Antioxidant Capacity and Total Polyphenol Content of the Extracts from Three Different Parts of Olive Plant and the Green Production of Iron Nano Particles (GInPs)

Determination of Antioxidant Capacity and Total Polyphenol Content of the Extracts from Three Different Parts of Olive Plant and the Green Production of Iron Nano Particles (GInPs)

Synthesis and Biological Activity of New Schiff Bases of Benzylideneamine Bearing Thiophene, 1,2,4-triazolone, 1,3,4-oxadiazole, Morpholine Moieties

Background: Schiff bases have a broad spectrum of biological activities including antiviral, antibacterial, antifungal, antimalarial, anti-inflammatory antiproliferative and antipyretic properties. 1,3,4-oxadiazoles have been reported to show spectrum of biological activities including such as antiviral, fungicidal, antineoplastic, antimicrobial anti-HIV, antitubercular, antihypoglycemic, antimalarial, antioxidant, analgesic, anti-inflammatory, anticonvulsant, anticancer and inhibition of tyrosinase, antitumor and antiproliferative. Morpholine is known as a valuable structure for the synthesis of more efficacious antimicrobial agents. Therefore, the study presents the synthesis, antimicrobial and antioxidant evaluation of a series of 1,3,4 substituted oxadiazole derivatives. Methods: Synthesis of compounds 2(a-d): 0.01 mol 4-amino-1-((5-mecapto-1,3,4-oxadiazol-2-yl) methyl)-3-(thiophen-2-ylmethyl)-1H-1,2,4-triazol-5(4H)-one (1) and 0.01 mol aromatic aldehydes were heated in oil bath without solvent for 2-3 h at 160-180 0C. Then on completion of the reaction, followed by TLC examination, allowed to cool to room temperature. The separated solid was filtered and crystallized from a mixture of DMSO and water (1:2). Synthesis of compounds 3(a-d). A mixture of formaldehyde (0.02 mol) and morpholine (0.02 mol) in DMF was added to solution of compound 2 (0.01 mol) in DMF. The resulting mixture was stirred overnight at room temperature. The precipitated solids were filtered, washed with water and recrystallized from DMF/water. Determination of Antioxidant Activity: The FRAP method was used for the determination of total antioxidant capacity, based on the reduction of yellow Fe3+ -TPTZ complex to the blue Fe2+ -TPTZ complex by electron donating substance under acidic condition. Radical scavenging activity of compounds against 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical was spectrophometrically at 517 nm. The assay is based on the color change of the DPPH solution from purple to yellow as the radical is deactivated by the antioxidants. Briefly, the stock solutions of each extract were prepared in DMSO and if necessary sequential dilutions were made. Results: All of the compounds synthesized in this study, except 3c, showed antioxidant activity in the free-radical scavenging (DPPH) and ferric reducing (FRAP) tests at different grades (Figs. 1 and 2). The antioxidant activities of the compounds were differentially influenced in the DPPH and FRAP tests from the substituents of Schiff and Mannich bases. It has been determined that the effects of the substituent type of the thiophene ring on the activity were different for Schiff bases (2ad) and Mannich bases (3a-d). High-to-low activity sequencing was H-CN-NO2-Br (in DPPH assay) and NO2-H-CN-Br (FRAP assay) on schiff bases while Br- H- NO2-CN (in DPPH assay) and H-Br- NO2-CN (in FRAP assay) on mannich bases. Similarly, in DPPH and FRAP assay, the Schiff bases (2a-d) were more active when compared with the Mannich bases (3a-d). Conclusion: In the work, new eight Schiff bases bearing thiophene, 1,2,4-triazolone, 1,3,4-oxadiazole, morpholine moieties were synthesized. The new compounds, well characterized by elemental analyses, IR, 1H NMR and 13C NMR were tested for their antioxidant and antimicrobial activities. In DPPH and FRAP assay, the compounds 2(a-d) with Schiff base were more active when compared with the compounds 3(a-d) containing Schiff base and morpholine substituent and 2(a-c) had a respectable antioxidant potential. The lowest MIC value, i.e. the highest antimicrobial activity, were observed in compound 2a against Bacillus cereus RSKK 709 with a MIC value of 31.25 µg/mL. Keywords: Schiff base, mannich base, morpholine, antimicrobial, antioxidant activities, MIC.

Evaluation of effect of different solvent mixtures on the phenolic compound extraction and antioxidant capacity of bitter melon (Momordica charantia)

The effect of 13 solvent combinations was evaluated on the determination of total phenolic content and antioxidant capacity of bitter melon (pulp, peel and seeds) using ultrasound. Among all solvents used, the ethanol/water combination (80:20, v/v) showed the best results for extraction process, with higher TPC content for all parts of the studied fruit. The highest antioxidant capacity by DPPH was observed in the extracts with pure acetone for pulp (2.18 ± 0.04 mg ET g−1), and ethanol/water (80:20, v/v) for the peel (7.20 ± 0.09 mg ET g−1) and for seeds (3.01 ± 0.05 mg ET g−1). As for ORAC assay the highest antioxidant capacities were noted in extracts with ethanol/water (80:20, v/v) for all parts of studied fruit. The recovery assays of ethanol/water (80:20, v/v) varied from 81.35 to 108.70% in all parts of fruit. A total of eight phenolic compounds were noted in bitter melon fruit, highlighting the pulp with 477.74 ± 14.49 μg g−1 of 4-hydroxybenzoic acid. Thus, the type of solvent used significantly affected the phenolic compounds extraction and the antioxidant capacity of all parts of bitter melon (pulp, peel and seeds). Bitter melon fruit is a source of antioxidants compounds, mainly the health-benefiting.

Supplementation with l-glutathione improves oxidative status and reduces protein nitration in myenteric neurons in the jejunum in diabetic Rattus norvegicus

Diabetes mellitus is a syndrome with multiple etiologies, characterized by chronic hyperglycemia that increases the production of reactive oxygen species and decreases antioxidant defenses. The present study evaluated oxidative stress parameters and protein nitration in myenteric neurons in the jejunum in diabetic rats supplemented with l-glutathione. Rats (90 days of age) were distributed into four groups (n = 6/group): normoglycemic (N), normoglycemic supplemented with l-glutathione (NGT), diabetic (D), and diabetic supplemented with l-glutathione (DGT). At 210 days of age, the animals were sacrificed, and the jejunum was collected, washed, and subjected to various procedures: tert-butyl hydroperoxide chemiluminescence (CL), determination of total antioxidant capacity (TAC), determination of catalase activity, quantification of nitric oxide (NO), and double-labeling of HuC/D-immunoreactive myenteric neurons and nitrotyrosine (3-NT). Diabetes increased oxidative stress in the jejunum in the D group, reflected by increases in lipid peroxidation, TAC, catalase activity, and NO. The D group exhibited an increase in the percentage of myenteric neurons that were double-labeled with 3-NT. Supplementation with l-glutathione did not cause differences in the average CL curves between the D and DGT groups, but reductions of TAC and catalase activity were observed. Supplementation with l-glutathione promoted a reduction of neurons that contained 3-NT in the DGT group. Diabetes mellitus promoted oxidative stress in the jejunum, and supplementation with l-glutathione improved oxidative status by preventing protein nitration in myenteric neurons in diabetic animals that received supplementation.

Programmable electrochemical flow system for high throughput determination of total antioxidant capacity

The aim of this work was to develop a programmable flow system for rapid assessment of total antioxidant capacity (TAC). Novel features of the prototype include a single pressure-driven source, versatile manipulation of fluid flows, ability to adapt to different TAC assays, and compatibility with microfluidic design. Antioxidant activity was determined by electrochemical measurement of residual 2,2-diphenyl-2-picrylhydrayl hydrate (DPPH•) free radicals in the solution. The overall performance of the device was validated by the spectrophotometric method. The results indicated that dosing of reagents and samples could be controlled by pressure (R2 = 0.992) and time (R2 = 0.999) with high accuracy, and the mixing uniformity of the device was equivalent to that of the batch mixing (R2 = 0.994). TAC assays of a standard antioxidant, ascorbic acid, as well as selected samples such as orange and pomegranate juices, white wine, and green tea by the device were comparable to traditional measurement techniques. Due to the short incubation time, the approach may be more suitable for fast, rather than slow reacting antioxidant compounds. The developed system could be used for rapid TAC screening of food and biological samples.

Urtica dioica L. leaf extract modulates blood pressure and oxidative stress in spontaneously hypertensive rats

BackgroundUrtica dioica L. (Stinging nettle) has been used for centuries for the treatment of numerous health issues. PurposeThis study investigates the antioxidant capacity and the most abundant phenolic compounds of Urtica dioica L. leaf extract (UE), and its antihypertensive and antioxidative effects in vivo. Study designSpontaneously hypertensive rats were supplemented with 10, 50, and 200 mg/kg/day of UE and 10 mg/kg/day of losartan during 4-week period. MethodsIn this study, HPLC analysis of UE was performed, as well as the determination of antioxidant capacity, superoxide radical scavenging activity, and metal chelating ability. Hemodynamic parameters were measured directly in anesthetized rats. Also, antioxidant enzyme activity and concentration in erythrocytes were determined, as well as systemic oxidative stress and plasma antioxidant status. ResultsUE showed higher ferric reducing antioxidant power and Trolox equivalent antioxidant capacity than BHT, but lower than vitamin C. Furthermore, UE showed good metal chelating ability, but weak superoxide radical scavenging activity. All three tested UE doses managed to reduce systolic and diastolic blood pressure, as well as cardiac index, and to improve the antioxidative defense by increasing the activity of superoxide dismutase and catalase, without changing the concentration of the enzymes. Moreover, UE supplementation increased plasma antioxidant capacity and reduced systemic oxidative stress. ConclusionChronic UE dietary supplementation had beneficial effects in the experimental model of essential hypertension.

Flow Injection Amperometric System Coupled with a Well-Plate for Fast Screening of Total Antioxidant Capacity

ABSTRACTA flow injection (FI) system with an amperometric detection in combination with a 96-well-plate has been developed for high throughput screening of total antioxidant capacity. It is based on the reaction between dichromate and antioxidants Chromium reducing antioxidant capacity (CHROMAC) assay. Antioxidant reduces dichromate leading to a decrease of dichromate concentration, in which reacts further with triiodide reagent. The slow reaction between antioxidant and dichromate takes place in parallel in a 96-well microplate, with the reaction time sufficiently long to reach steady state conditions. Microliter volumes of the remaining dichromate solution were manually injected into the FI amperometric system. Reaction with iodide in acidic medium produces triiodide which undergoes electrochemical reduction on a glassy carbon working electrode at 200 mV versus a Ag/AgCl reference electrode. The decrease of electrical current was directly proportional to the antioxidant capacity. The optimum conditions have been achieved as follow: 160 mg L−1 of potassium dichromate, pH of dichromate solution of 2.82, 0.005 mol L−1 of potassium iodide, 0.20 mol L−1 of hydrochloric acid, and 3.0 mL min−1 total flow rate. The developed method was applied for the determination of total antioxidant capacity of tea and herbal infusions and fruit juice samples. The results obtained indicated that the developed method had good correlation with the batch CHROMAC spectrophotometric method and 1,1-diphenyl-2-picrylhydrazyl scavenging assay. The proposed method provides fast and high throughput analysis, convenient operation, and low consumption of chemical reagents and samples.

The Correlation Between Serum Vitamin D Level and Total Antioxidant Capacity in diabetic and Non-diabetic Subjects in Iran

Increase in intraand extracellular glucose levels can cause oxidative stress, and theprolonged imbalance between prooxidants and antioxidantscan lead to cell damage and the associated complications in patients with diabetes. Vitamin D acts as a strong antioxidant in the body and several studies emphasized on its important role to preventoxidative stress in prediabeticand diabetic subjects. The current study aimed at determining and comparingthe total antioxidant capacity (TAC) in individuals with hemoglobin A1c(HbA1c) below and above 6.5%, and its correlation with vitamin D levels. The current cross sectional study was conducted on a total of 107patients with diabetes (HbA1c >6.5%) and 107 non-diabetic subjects (HbA1c<6.5%)referred toRassoolAkram Hospital, Tehran, Iranfrom2015 to 2016, as the sample population. The two groups were compared regarding their TAC and vitamin D serum levels and the association between vitamin D concentration and TAC was evaluated. Age and body mass index (BMI)were significantly higher in patients with diabetes,comparedwiththe serum levels of vitamin D and TAC (P<0.001 for both). Both TAC and vitamin D levels were significantly lower in the group with diabetesand a weak significant correlation was observedbetween the two factors (r=0.2, P=0.003). In multivariate regression model, the duration of diabetes was also significantly associated with TAC level (beta coefficient=-0.82, P <0.001). The low serum levels of TAC and vitamin D in patients with diabetescould be indicative of oxidative stress in the presence of high blood glucose levels. Supplementation of vitamin D in patients with diabetes might be effective to control thenegative impacts of the disease and decreasecells' exposure to oxidative environment in prediabetes.

Fast Determination of Antioxidant Capacity of Food Samples Using Continuous Amperometric Detection on Polyester Screen‐printed Graphitic Electrodes

AbstractThe determination of antioxidant capacity of food samples using disposable polyester screen‐printed graphitic macroelectrodes (SPGE) coupled with a batch‐injection cell based on the measurement of the consumption of 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH.) is reported. The SPGEs are organic‐resistant electrodes and thus compatible with food samples and organic solvents used to dissolve DPPH.. A micropipette controlled the release (193 μL s−1) of sample (150 μL) upon the sensor/working electrode immersed in electrolyte (1 : 1 ethanol/methanol containing 0.05 mol L−1 LiCl). The first demonstration of this protocol was devoted to the analysis of edible oils. The remaining DPPH. was amperometrically detected at +0.1 V (vs. pseudo AgCl). The antioxidant capacity (percentage of DPPH. scavenging and mg equivalent of tocopherol) was obtained using the proposed and spectrophotometric methods. The results were in agreement according to t‐test (confidence level of 95 %). The method is precise (RSD=2.3 %, n=12), fast (180 h−1), presents low detection limit of DPPH. (1 μmol L−1), and allows on‐site analysis. Moreover, the proposed method can be extended to the analysis of antioxidant capacity of other samples of agricultural and food interests.

Content of endogenous sulfur dioxide in wines

Content of free and total endogenous sulfur dioxide were evaluated by classical iodometric titration in must, during winemaking processes and in bio-wine. No exogenous sulfur dioxide was added in any technological operations to simplify the evaluations. In addition, the results were corrected on the content of reductons (total content of reducing substances). The results confirmed formation of endogenous sulfur dioxide from sulfur containing substances (sulfur containing amino acids etc.) in both experiments. Microbial sulfur dioxide is preferably bound to carbonyl substances. Only minor part is present in the free (active) form of the sulfur dioxide. In addition, total content of polyphenols (TPC) and total antioxidant capacity (TAC) were determined by spectrophotometry at the same time. A procedure OIV-MA-AS323-O4B: R 2009 was used. Contents of "free" and "total" sulfur dioxide (with/without correction on contents of reductons) and total content of reductones were determined after complexing the sulfur dioxide with formaldehyde. A standard spectrophotometric method using Folin-Ciocalteu reagent was applied for determination of total content of polyphenolics (TPC) at 765 nm after 60 min incubation. The results were expressed as tannin equivalents (in mg.L-1). A standard DPPH (2,2´-difenyl-1-picrylhydrazyl dissolved in methanol) spectrophotometric method was applied for determination of total antioxidant capacity (TAC) at 515 nm. Depletion of the color intensity was measured after 60 min incubation against blank (methanol) and absorbance decrease Δ(A) = (A0 - A1)/A0 was calculated and used for construction of calibration curve. The TAC values were expressed as ascorbic acid concentrations (in mg.L-1).

Determination of antioxidant capacity of thiol-containing compounds by electron spin resonance spectroscopy based on Cu2+ ion reduction

Electron spin resonance spectroscopy was applied to determining the antioxidant capacity of eight thiol-containing compounds, including reduced glutathione, N-acetyl-L-cycsteine, methimazole, captopril, and tiopronin with one thiol group, 1,4-dithioerythritol and 2,3-dimercapto-1-propanol with two thiol groups, as well as L-cystine with no free thiol group. Cu2+ ion gives an electron spin resonance signal and is reduced to Cu+ ion with no electron spin resonance signal by the free thiol group in the compounds. Trolox equivalent antioxidant capacity (TEAC) was used to evaluate the reducing ability of the thiol-containing compounds and the TEAC values were found to be relevant to the number of thiol groups contained in the compounds. For the purpose of comparison, the UV-vis spectrophotometry, cupric reducing antioxidant capacity (CUPRAC) method, and Ellman assay were applied to the determination of the antioxidant capacity of the thiol-containing compounds. The TEAC values obtained by the present method were very close to those obtained by UV-vis method. However, compared with CUPRAC method, for methimazole the present method gave a more reasonable TEAC value. The present method was also applied to the quantification of N-acetyl-L-cycsteine, methimazole, captopril, and tiopronin in their pharmaceutical formulations.

The protective effect of melatonin on sperm quality in rat after radioiodine treatment.

This study was designed to investigate the potential radioprotective impact of melatonin on the testicular tissue and sperm quality in rat given radioactive iodine (RAI) therapy. Thirty-six male Wistar albino rats were randomly divided into three groups as untreated control (Group 1); oral radioiodine group (RAI, 111 MBq, administrated rats); and RAI+melatonin group (oral radioiodine and intraperitoneal 12 mg/kg/day melatonin, starting 2days before and continuing for 1week after oral RAI administration). Twenty-four hours after the injection of the last melatonin dose, blood samples were taken for hormone analyses and the determination of the total antioxidant capacity. Sperm samples taken from the cauda epididymis were examined for spermatological parameters. Tissue samples taken from the rat testes were stained by TUNEL assay and with haematoxylin-eosin to detect apoptosis and histological alterations. It was demonstrated a significant decrease in epididymal spermatozoa viability and motility in all of the treatment groups, in comparison with the control group (p<.001). A significant decrease was also detected in sperm DNA fragmentation, follicle-stimulating hormone (FSH) level and the index of apoptotic germ cells in the RAI+melatonin group when compared to the radioiodine group. It was concluded that melatonin prevents the adverse affects of RAI on apoptosis and spermatozoa quality.

Determination of triterpenoids, carotenoids, chlorophylls, and antioxidant capacity in Allium ursinum L. at different times of harvesting and anatomical parts

Triterpenoids, carotenoids, chlorophylls, and antioxidant capacity of individual parts of wild garlic at different times of harvesting were studied. Leaves, flowers, bulbs, and stems of Allium ursinum were used in this study. The contents of triterpenoids, carotenoids, and chlorophylls were determined by UPLC–PDA-Q/TOF-MS, and the antioxidant capacity was determined by ABTS and FRAP assay. A total of 21 compounds including 3 triterpenoids, 11 carotenoids, and 7 chlorophylls were identified in anatomical parts of A. ursinum in March and June 2016. These compounds present in individual anatomical parts of wild garlic were determination in this study for the first time ever. The average content of total triterpenoids ranged from 750.7 to 4159.5 mg/kg dry matter (dm) and that of carotenoids and chlorophylls ranged from 14.4 to 14,424.5 mg/kg dm for bulbs and leaves. The average level of the antioxidant capacity ranged from 37.1 to 91.7 µmol Trolox/g dm in bulbs and leaves, respectively. The leaves, flowers, and stems of wild garlic are a good source of health-promoting compounds. They can be used as functional food ingredients, dietary supplements, and additives.

Square wave voltammetric analysis of polyphenol content and antioxidant capacity of red wines using glassy carbon and disposable carbon nanotubes modified screen-printed electrodes

The polyphenols present in different French red wines were characterized electrochemically using square wave voltammetry (SWV). The voltammetric measurements were carried out using a glassy carbon electrode and disposable screen-printed carbon electrodes unmodified and modified with single- and multi-walled carbon nanotubes. The single-walled carbon nanotubes-modified screen-printed carbon electrode (SWCNTs-SPCE) showed the best results for the voltammetric analysis of polyphenols in red wine samples, allowing using disposable electrodes to perform measurements. The obtained voltammograms contained three characteristic oxidation peaks. The first peak at the lowest potential was ascribed to oxidation of catechol and galloyl groups of polyphenols (on the flavonoid B-ring), the second peak to the oxidation of malvidin anthocyanins and the third peak was due mainly to the second oxidation wave of flavonoid phenolic groups. The total polyphenols content was determined by spectrophotometric and chromatographic methods as well as antioxidant capacity by the ABTS method, and were in good agreement with the SWCNTs-SPCE results. Thus, SWV is a satisfying fast electrochemical technique for the polyphenol characterization and antioxidant capacity determination of red wine compared to the more frequently used cyclic voltammetry or differential pulse voltammetry, especially using SWCNTs-SPCE.

Phenolic compounds, antioxidant capacity and physicochemical properties of Brazilian Apis mellifera honeys

Forty-nine honey samples from five monofloral (eucalyptus, mastic, wildflower, Japanese grape and quitoco) and six polyfloral honeys were analyzed for their physicochemical and antioxidant compounds. Levels of total phenolics and flavonoids as well as individual composition were analyzed by HPLC. The oxygen radical absorption capacity (ORAC), the ferric reducing antioxidant power (FRAP), and the 2,2-diphenyl-1-picrylhydrazyl free radical assays (DPPH) were performed to determine antioxidant capacity. The highest antioxidant capacity was observed in eucalyptus and mastic honeys; gallic acid levels were greatest in both of them while p-coumaric acid was highest in Japanese grape honey. Physicochemical and antioxidant properties of honey were found to be dependent on its botanical origin. Linear discriminant analysis was able to differentiate 90% of honeys in terms of the seasons when they were collected and the main discriminant responses were p-coumaric acid, titratable acidity, diastase activity, and total flavonoids content. LDA correctly classified 96% of honeys according to their botanical origin.

Determination of Antioxidant Capacity, Flavonoids and Total Phenolic Content of Extracts from Atractylis flava Desf

objective: The aim of the present study was to evaluate the ability of different extracts (PE, DCM, EtAOc and n-BuOH) obtained from Atractylis flava Desf to prevent oxidation using several methods in vitro. Materials and Methods: The capacity of samples for scavenging free radicals (ABTS+, DPPH), preventing lipid peroxidation (s-carotene), chelating metal ions, CUPRAC, reducing power. The quantification of total phenols was performed using Folin-Ciocalteu reagent and the total flavonoid content was performed by the trichloroaluminum method. Results: The highest concentrations of total polyphenols and flavonoids were found in the n-BuOH extract (122,74 ± 0,78 µg GAE/ml and 66,75±6,12 µg QE/ml, respectively). EtAOc and n-BuOH extracts were the most active for scavenging DPPH (IC50 = 158,41±3,24 and IC50 = 427,53±4,69 µg/mL, respectively), and EtAOc extract was also the best for scavenging ABTS+ radicals (IC50 = 15,57±2,93 µg/mL). EtAOc extract possessed the best capacity for preventing lipid peroxidation (IC50 = 16,52±1,87 µg/mL) and CUPRAC assay (A0.50 = 28,58±0,65 µg/mL). The results of ferric reducing power ability of all the tested samples were affected in a dose-dependent manner. Conclusions: These results suggest that Atractylis flava Desf have strong antioxidant potential. Further study is necessary for isolation and characterization of t of the active antioxidant agents, which can be used to treat various oxidative stress-related diseases.