ascorbic-acid and 2-2--azino-di-(3-ethylbenzothiazoline)-6-sulfonic-acid

The study of antioxidants and their implications in various fields, from food engineering to medicine and pharmacy, is of major interest to the scientific community. The present paper is a critical presentation of the most important tests used to determine the antioxidant activity, detection mechanism, applicability, advantages and disadvantages of these methods. Out of the tests based on the transfer of a hydrogen atom, the following were presented: the Oxygen Radical Absorption Capacity (ORAC) test, the Hydroxyl Radical Antioxidant Capacity (HORAC) test, the Total Peroxyl Radical Trapping Antioxidant Parameter (TRAP) test, and the Total Oxyradical Scavenging Capacity (TOSC) test. The tests based on the transfer of one electron include the Cupric Reducing Antioxidant Power (CUPRAC) test, the Ferric Reducing Antioxidant Power (FRAP) test, the Folin-Ciocalteu test. Mixed tests, including the transfer of both a hydrogen atom and an electron, include the 2,2'-Azinobis-(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) test, and the [2,2-di(4-tert-octylphenyl)-1-picrylhydrazyl] (DPPH) test. All these assays are based on chemical reactions and assessing the kinetics or reaching the equilibrium state relies on spectrophotometry, presupposing the occurrence of characteristic colours or the discolouration of the solutions to be analysed, which are processes monitored by specific wavelength adsorption. These assays were successfully applied in antioxidant analysis or the determination of the antioxidant capacity of complex samples. As a complementary method in such studies, one may use methods based on electrochemical (bio)sensors, requiring stages of calibration and validation. The use of chemical methods together with electrochemical methods may result in clarification of the operating mechanisms and kinetics of the processes involving several antioxidants.

Topics: Animals; Antioxidants; Ascorbic Acid; Benzothiazoles; Biological Assay; Biphenyl Compounds; Electrochemical Techniques; Free Radical Scavengers; Humans; Hydrogen; Hydroxyl Radical; Kinetics; Oxygen; Phenols; Picrates; Reactive Oxygen Species; Sulfonic Acids; Superoxide Dismutase

Considering the pathologic importance of oxidative stress and altered lipid metabolism in osteoarthritis (OA), this study aimed to investigate the effect of l-carnitine supplementation on oxidative stress, lipid profile, and clinical status in women with knee OA. We hypothesized that l-carnitine would improve clinical status by modulating serum oxidative stress and lipid profile. In this randomized double-blind, placebo-controlled trial, 72 overweight or obese women with mild to moderate knee OA were randomly allocated into 2 groups to receive 750 mg/d l-carnitine or placebo for 8 weeks. Dietary intake was evaluated using 24-hour recall for 3 days. Serum malondialdehyde (MDA), total antioxidant capacity (TAC) and lipid profile, visual analog scale for pain intensity, and patient global assessment of severity of disease were assessed before and after supplementation. Only 69 patients (33 in the l-carnitine group and 36 in the placebo group) completed the study. l-Carnitine supplementation resulted in significant reductions in serum MDA (2.46 ± 1.13 vs 2.16 ± 0.94 nmol/mL), total cholesterol (216.09 ± 34.54 vs 206.12 ± 39.74 mg/dL), and low-density lipoprotein cholesterol (129.45 ± 28.69 vs 122.05 ± 32.76 mg/dL) levels compared with baseline (P < .05), whereas these parameters increased in the placebo group. Serum triglyceride, high-density lipoprotein cholesterol, and TAC levels did not change significantly in both groups (P > .05). No significant differences were observed in dietary intake, serum lipid profile, MDA, and TAC levels between groups after adjusting for baseline values and covariates (P > .05). There were significant intragroup and intergroup differences in pain intensity and patient global assessment of disease status after supplementation (P < .05). Collectively, l-carnitine improved clinical status without changing oxidative stress and lipid profile significantly in women with knee OA.

Topics: Ascorbic Acid; Benzothiazoles; Body Mass Index; Carnitine; Cholesterol, HDL; Cholesterol, LDL; Dietary Fats; Dietary Proteins; Dietary Supplements; Double-Blind Method; Energy Intake; Female; Humans; Lipid Metabolism; Malondialdehyde; Middle Aged; Motor Activity; Nutrition Assessment; Obesity; Osteoarthritis, Knee; Overweight; Oxidative Stress; Selenium; Sulfonic Acids; Thiobarbiturates; Triglycerides; Vitamin A; Vitamin E; Zinc

Physalis peruviana L. fruit contains nutritional and bioactive compounds of immense importance to public health and represents a potential ingredient for the development of functional foods and beverages.. This study aimed to determine the chemical and nutritional composition as well as the antioxidant capacity of the P. peruviana L. fruit grown in Peru in three areas of the Central Andean region.. Proximal and physicochemical analyses and estimation of mineral content, vitamin C, total carotenoids, total polyphenols, and antioxidant capacity (2, 2-diphenyl-1-picrylhydrazyl [DPPH] and 2, 2'-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) [ABTS] assays) were performed using standardized methods.. The fruits were collected from three regions of the Peruvian Andes (Ancash, Cajamarca, and Cusco). The results showed that the content of potassium (306.54-327.60 mg/100 g) and iron (12.93-14.47 mg/kg) was prominent. The Physalis fruit had high levels of vitamin C (47.20-52.20 mg/100 g), total polyphenols (68.17-83.40 mg equivalents of gallic acid/100 g), and carotenoids (1.12-1.73 mg β-carotene/100 g). Higher values for antioxidant capacity were obtained with the ABTS method (896-1003.33 μmol Trolox/100 g) than with the DPPH method (290-309 μmol Trolox/100 g).. This study confirms that the P. peruviana fruit has properties that could provide important health benefits and that it could be used for the development of functional foods and food supplement.

Topics: Antioxidants; Ascorbic Acid; Carotenoids; Fruit; Humans; Peru; Physalis; Plant Extracts; Polyphenols; Vitamins

This study reported the isolation and identification of bioactive compounds from Dioscorea nipponica Makino, a plant used in traditional medicine for various ailments. Nine compounds were isolated, including a new compound named as diosniposide E, which was elucidated by analyzing its

Topics: Antioxidants; Ascorbic Acid; Dioscorea; Magnetic Resonance Spectroscopy

Topics: Acetylcholinesterase; Actinidia; Antioxidants; Ascorbic Acid; Catechin; Cholinergic Antagonists; Fruit; Plant Extracts; Polyphenols

An unrecorded wild mushroom Lactarius hatsudake from Nanyue mountainous region in China was identified. Subsequently, comparative investigation on the nutritional value, elemental bioaccumulation, and antioxidant activity was performed in the fruiting body (FB) and mycelium (MY) samples of this species. It revealed that the contents of moisture (87.66 ± 0.16 g/100 g fw) and ash (6.97 ± 0.16 g/100 g dw) were significantly higher in FB, and the total carbohydrate, fat, and protein concentrations of FB were similar to those in MY. Among nutritionally important elements, FB possessed higher concentrations of potassium (37808.61 ± 1237.38 mg/kg dw), iron (470.69 ± 85.54 mg/kg dw), and zinc (136.13 ± 5.16 mg/kg dw), whereas MY was a better source of magnesium (1481.76 ± 18.03 mg/kg dw), calcium (2203.87 ± 69.61 mg/kg dw), and sodium (277.44 ± 22.93 mg/kg dw). According to the health risk estimation, FB might pose an aluminum-related health problem when a prolonged period of exposure, while MY was risk-free for consumers. The results of antioxidant capacity (1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-Azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) assays) in FB and MY were within the range of 104.19 ± 5.70 mg ascorbic acid equivalents (AAE)/g to 169.50 ± 4.94 mg AAE/g, and half maximal effective concentration EC50 values ranged from 0.23 ± 0.01 mg/mL to 0.62 ± 0.05 mg/mL. The aqueous extracts of MY demonstrated a strong ABTS radical scavenging capacity with the highest AAE value.

Topics: Antioxidants; Ascomycota; Ascorbic Acid; Bioaccumulation; Fruiting Bodies, Fungal; Mycelium; Nutritive Value

Developing functional foods by utilizing plants can often lead to compromised sensory properties. Thus this study investigates the combination of plants to produce synergistic effects and to incorporate these plant powders into a pasta formulation without affecting its sensory acceptance. Six common Brunei medicinal plants were evaluated for their in vitro antioxidant activity determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity (IC. Fortification of pasta with the plant powder blends resulted a significant increase in DPPH antioxidant activity, while successfully maintaining indistinguishable features from the control pasta, including minimal cooking loss, agreeable measure of cohesiveness, springiness and chewiness, with good overall sensory acceptability. © 2022 Society of Chemical Industry.

Topics: Amaranthus; Antioxidants; Ascorbic Acid; Brunei; Gallic Acid; Plant Extracts; Plants, Medicinal; Powders; Triticum

The use of higher plants for the production of plant growth biostimulants is receiving increased attention among scientists, farmers, investors, consumers and regulators. The aim of the present study was to examine the possibility of converting plants commonly occurring in Europe (St. John's wort, giant goldenrod, common dandelion, red clover, nettle, valerian) into valuable and easy to use bio-products. The biostimulating activity of botanical extracts and their effect on the chemical composition of celeriac were identified. Plant-based extracts, obtained by ultrasound-assisted extraction and mechanical homogenisation, were tested in field trials. It was found that the obtained formulations increased the total yield of leaves rosettes and roots, the dry weight of leaves rosettes and roots, the content of chlorophyll

Topics: Antioxidants; Apium; Ascorbic Acid; Benzothiazoles; Biphenyl Compounds; Carotenoids; Chemistry, Pharmaceutical; Chlorophyll; Chlorophyll A; Europe; Fatty Acids; Horticulture; Nitrates; Photosynthesis; Picrates; Pigmentation; Plant Extracts; Plant Leaves; Plant Roots; Polyphenols; Sulfonic Acids; Ultrasonics

Twelve N-hydroxycinnamoyl amino acid amide ethyl esters (CAES) were synthesized by using l-amino acid ethyl ester hydrochloride and corresponding cinnamic acid (ferulic acid, acetylferulic acid and caffeic acid) as raw materials in the presence of a catalytic amount of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide-hydrochloride (EDC) and 1-hydroxybenzotriene (HOBt). The 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activities of CAES were evaluated. The anti-tyrosinase activities of N-feruloyl amino acid ethyl esters and the hydroxyl (OH) free radical scavenging activities of N-caffeoyl amino acid ethyl esters were also examined. DPPH free radical scavenging activity was shown in all CAES, of which N-caffeoyl amino acid ethyl esters demonstrated higher radical scavenging activity than N-feruloyl amide derivatives, and (E) -N-(caffeic acid)-l-glycinate ethyl ester (c

Topics: Agaricales; Amides; Antioxidants; Benzothiazoles; Cinnamates; Dose-Response Relationship, Drug; Enzyme Inhibitors; Molecular Structure; Monophenol Monooxygenase; Structure-Activity Relationship; Sulfonic Acids

Among several potential applications, sigma receptors (σRs) can be used as neuroprotective agents, antiamnesic, antipsychotics and against other neurodegenerative disorders. On the other hands, antagonists of the GluN2b-subunit-containing-N-methyl-D-aspartate (NMDA) receptors are of major interest for the same purpose, being this subunit expressed in specific areas of the central nervous system and responsible for the excitatory regulation of nerve cells. Under these premises, we have synthesized and biologically tested novel hybrid derivatives obtained from the combination of phenyloxadiazolone and dihydroquinolinone scaffolds with different amine moieties, peculiar of σ2R ligands. Most of the new ligands exhibited a pan-affinity towards both σR subtypes and high affinity against GluN2b subunit. The most promising compounds belong to the dihydroquinolinone series, with the best affinity profile for the cyclohexylpiperazine derivative 28. Investigation on their biological activity showed that the new compounds were able to protect SH-SY5Y cells against oxidative stress induced by hydrogen peroxide treatment. These results proved that our dual σR/GluN2b ligands have beneficial effects in a model of neuronal oxidative stress and can represent strong candidate pharmacotherapeutic agents for minimizing oxidative stress-induced neuronal injuries.

Topics: Antioxidants; Benzothiazoles; Cell Line, Tumor; Dose-Response Relationship, Drug; Drug Discovery; Humans; Hydrogen Peroxide; Ligands; Models, Molecular; Molecular Structure; Neuroprotective Agents; Oxadiazoles; Oxidative Stress; Quinolones; Receptors, N-Methyl-D-Aspartate; Receptors, sigma; Structure-Activity Relationship; Sulfonic Acids

Bistorta amplexicaulis is a popular medicinal plant and reported as rich source of antioxidant compounds. The present study was designed for antioxidant and anticancer potential of polarity based fractions of B. amplexicaulis and its correlation to the secondary metabolites quantified by HPLC-UV/VIS.Crude extract was prepared by maceration method and polarity based fractions were prepared by solvent-solvent extraction. Antioxidant and anticancer potential was investigated by using various physiological and non-physiological assays while secondary metabolites rutin, naringin and quercetin present in extract and fractions were quantified by using HPLC- UV/VIS. All extracts showed Antioxidant potential but highest activity was obtained with ethyl acetate fraction (DPPH IC50 5.76±0.03 µg/ml, ABTS IC50 0.74±0.1 µg/ml, Total Antioxidant Assay 72.55±0.098 Ascorbic acid equivalents, Super oxide radical scavenging assay IC506.86±0.1909 µg/ml, Hydroxyl radical scavenging assay IC50 0.96±0.1690 µg/ml). The cytotoxicity of fractions against HepG2 cell lines showed lowest ell viability in n-hexane fraction (11%). The results revealed that ethyl acetate fraction of B. amplexicaulis can be a potential source of novel antioxidant compounds while n hexane fraction could provide anticancer compounds. A new method of simultaneous quantification of three flavonoids by using UV/VIS detector is reported in this study.

Topics: Antineoplastic Agents; Antioxidants; Ascorbic Acid; Benzothiazoles; Chemical Fractionation; Chromatography, High Pressure Liquid; Flavonoids; Free Radical Scavengers; Free Radicals; Hep G2 Cells; Humans; Lipid Peroxidation; Phenols; Plant Extracts; Polygonaceae; Reference Standards; Rhizome; Secondary Metabolism; Sulfonic Acids; Ultraviolet Rays; Vitamin E

This study investigates the effects of bovine serum albumin (BSA) on blueberry anthocyanins and their interaction. Findings showed that BSA could protect blueberry anthocyanins against degradation and retain their antioxidant activity at an ideal concentration of 0.15 mg/mL under three deteriorating treatments: illumination, vitamin C + illumination, and sucrose + illumination. The fluorescence and UV absorption spectra showed that malvidin-3-o-galactoside (M3G), the major monomer in blueberry anthocyanins, led to a static quenching of BSA and the binding site of M3G to BSA was approximately one. Further, the interaction was a spontaneous process with electrostatic interactions being the main force. CD spectra and synchronous fluorescence spectra presented alterations in the secondary structure and microenvironment of Trp and Tyr residues of BSA, respectively, upon interaction with M3G. Finally, molecular docking analysis showed that M3G mainly bound the II and III domains of BSA by hydrogen bonds and electrostatic interaction. In conclusion, our study highlights the protective effects of BSA on the stability and anti-oxidant activity of blueberry anthocyanins and their interaction analysis.

Topics: Anthocyanins; Antioxidants; Ascorbic Acid; Benzothiazoles; Binding Sites; Blueberry Plants; Circular Dichroism; Hydrogen Bonding; Light; Molecular Docking Simulation; Serum Albumin, Bovine; Spectrometry, Fluorescence; Spectrophotometry, Ultraviolet; Static Electricity; Sucrose; Sulfonic Acids; Thermodynamics; Tryptophan; Tyrosine

Parkinson's disease (PD) is a neurodegenerative disorder characterised by the death of dopaminergic neurons in the substantia nigra pars compacta (SNpc) region of the brain and formation of α-synuclein-containing intracellular inclusions. Excess intraneuronal iron in the SNpc increases reactive oxygen species (ROS), which identifies removing iron as a possible therapeutic strategy. Desferrioxamine B (DFOB, 1) is an iron chelator produced by bacteria. Its high Fe(iii) affinity, water solubility and low chronic toxicity is useful in removing iron accumulated in plasma from patients with transfusion-dependent blood disorders. Here, lipophilic analogues of DFOB with increased potential to cross the blood-brain barrier (BBB) have been prepared by conjugating ancillary compounds onto the amine terminus. The ancillary compounds included the antioxidants rac-6-hydroxy-2,5,7,8-tetramethylchromane-2-carboxylic acid (rac-trolox, rac-TLX (a truncated vitamin E variant)), R-TLX, S-TLX, methylated derivatives of 3-(6-hydroxy-2-methylchroman-2-yl)propionic acid (α-CEHC, γ-CEHC, δ-CEHC), or 4-(5-hydroxy-3-methyl-1H-pyrazol-1-yl)benzoic acid (carboxylic acid derivative of edaravone, EDA). Compounds 2-8 could have dual function in attenuating ROS by chelating Fe(iii) and via the antioxidant ancillary group. A conjugate between DFOB and an ancillary unit without antioxidant properties (3,5-dimethyladamantane-1-carboxylic acid (AdA

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; Animals; Antioxidants; Ascorbic Acid; Benzothiazoles; Blood Proteins; Deferoxamine; Disease Models, Animal; Iron; Iron Chelating Agents; Mice; Nerve Degeneration; Neurons; Parkinson Disease; Sulfonic Acids

Nanozymes are metal nanoparticles with catalytic properties that can be used to oxidise peroxidase substrates giving a colorimetric response which can be detected using UV-vis, and recently, Raman spectroscopy. Due to their ease of synthesis and increased stability, nanozymes are being increasing investigated to replace conventional enzymes for the detection of biomolecules. Here we exploit the catalytic activity of iron oxide (Fe

Topics: Antioxidants; Ascorbic Acid; Benzothiazoles; Chlorogenic Acid; Ferric Compounds; Glutathione; Nanoparticles; Sulfonic Acids

This study aimed to characterize the effects of chitosan-g-caffeic acid (CTS-g-CA) on improving the quality and extending the shelf life of postharvest mulberry fruit during storage at 4 °C for 18 d. CTS-g-CA was enzymatically synthesized using laccase from Pleurotus ostreatus as a catalyst. The synergistic effects of CTS-g-CA treatment on mulberry fruit were evaluated using a co-toxicity factor (cf). The results showed that the rotting rate of CTS-g-CA-treated fruit was 37.67% (compared with that of the control at 97.67%) on day 18. The weight loss and malondialdehyde (MDA) contents of the CTS-g-CA-treated mulberry fruit were significantly lower (P < 0.05) than those of the control, CA, CTS, and CA+CTS treatments. Moreover, the DPPH and ABTS radical scavenging activities of the CTS-g-CA treatment were both higher than those of the control. Furthermore, the CTS-g-CA treatment also maintained higher levels of main active substances, such as anthocyanins, ascorbic acid, polyphenols and flavones, in mulberry fruit than the other treatments. Therefore, CTS-g-CA could be used to improve the quality and extend the shelf life of postharvest mulberry fruit during cold storage.

Topics: Anthocyanins; Antioxidants; Ascorbic Acid; Benzothiazoles; Biphenyl Compounds; Caffeic Acids; Chitosan; Cold Temperature; Food Handling; Food Preservation; Food Storage; Fruit; Humans; Malondialdehyde; Morus; Picrates; Polyphenols; Refrigeration; Sulfonic Acids

Syzygium jambos has been used as a traditional medicine for the treatment of inflammatory diseases in Bangladesh. The study investigates the high performance liquid chromatography (HPLC) profiling of phenolic compounds, and evaluates the antioxidant and anti-inflammatory activities of ethanol extract of S. jambos available in Bangladesh.. The extract was subjected to HPLC for the identification and quantification of the major bioactive polyphenols present in S. jambos. Antioxidant activity was determined using 2, 2'-azino bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical scavenging, reducing power assay, total antioxidant capacity, total phenolic and flavonoid content. Furthermore, the anti-inflammatory effect of the extract in rats for two different test models: carrageenan and histamine-induced paw edema was inspected.. High levels of catechin hydrate and rutin hydrate (99.00 and 79.20 mg/100 g extract, respectively) and moderate amounts of ellagic acid and quercetin (59.40 and 69.30 mg/100 g extract, respectively) were quantified in HPLC. Catechin hydrate from this plant extract was determined for the first time through HPLC. For ABTS scavenging assay, the median inhibition concentration (IC50) value of S. jambos was 57.80 µg/ml, which was significant to that of ascorbic acid (12.01 µg/ml). The maximum absorbance for reducing power assay was found to be 0.4934. The total antioxidant capacity, phenolic and flavonoid contents were calculated to be 628.50 mg/g of ascorbic acid, 230.82 mg/g of gallic acid and 11.84 mg/g of quercetin equivalent, respectively. At a dose of 400 mg/kg, a significant acute anti-inflammatory activity (P < 0.01) was observed in rats for both the test models with a reduction in the paw volume of 58.04 and 53.95 %, in comparison to those of indomethacin (62.94 and 65.79 %), respectively.. The results suggest that the phenolic and flavonoid compounds are responsible for acute anti-inflammatory and antioxidant activities of S. jambos.

Topics: Animals; Anti-Inflammatory Agents; Antioxidants; Ascorbic Acid; Bangladesh; Benzothiazoles; Chromatography, High Pressure Liquid; Edema; Ethanol; Flavonoids; Free Radical Scavengers; Histamine; Indomethacin; Male; Oxidation-Reduction; Plant Extracts; Polyphenols; Rats, Wistar; Sulfonic Acids; Syzygium

Two new indole alkaloids chaetocochin J (1) and chaetoglobinol A (8), along with chetomin (2), chetoseminudin A (3), cochliodinol (9), and semicochliodinol (10), were isolated from the rice culture of the fungus Chaetomium globosum. Their structures were elucidated by spectral analysis. Three new epipolythiodioxopiperazines, chaetocochins G-I (5-7), were identified by the combination of UPLC and mass spectrometric analysis. Chaetocochin I contained two sulfur bridges, one formed by three sulfur atoms between C-3 and C-11a, and the other formed by four sulfur atoms between C-3' and C-6'. Chaetocochin I was readily transformed into chetomin (2), chetoseminudin A (3), chaetocochin D (4), chaetocochin G (5), and chaetocochin H (6) by losing sulfur atoms. Compounds 1-3, and 8 exhibited antibacterial activities against Bacillus subtilis with MICs of 25, 0.78, 0.78, and 50 μg/mL, respectively, but not against Gram-negative bacterium (Escherichia coli). Compounds 2 and 8 were inactive against Candida albicans, Fusarium graminearum, Fusarium vasinfectum, Saccharomyces cerevisiae, and Aspergillus niger even at the high concentrations of 200 and 100 μg/mL, respectively. Compound 8 showed free radical scavenging capacity against the 1,1-diphenyl-2-picryl-hydrazyl (DPPH) and 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid radical (ABTS(+•)), with IC50 values of 143.6 and 45.2 μM, respectively. The free radical scavenging capacity rates of compounds 1-3 on the DPPH and ABTS(+•) were less than 20% at the test concentrations (89.9-108.3 μM). The superoxide anion radical scavenging assay indicated that compounds 1-3, and 8 showed 14.8% (90.9 μM), 18.1% (90.9 μM), 51.5% (88.3 μM), and 30.4% (61.3 μM) superoxide anion radical scavenging capacity, respectively.

Topics: Anti-Bacterial Agents; Bacillus subtilis; Benzothiazoles; Biphenyl Compounds; Chaetomium; Escherichia coli; Indole Alkaloids; Microbial Sensitivity Tests; Molecular Structure; Nuclear Magnetic Resonance, Biomolecular; Oryza; Picrates; Piperazines; Sulfonic Acids

The objective of this study was to evaluate the effect of Curcuma longa powder and ascorbic acid on some quality traits of rabbit burgers. The burgers (burgers control with no additives; burgers with 3.5 g of turmeric powder/100g meat; burgers with 0.1g of ascorbic acid/100g meat) were analyzed at Days 0 and 7 for pH, color, drip loss, cooking loss, fatty acid profile, TBARS, antioxidant capacity (ABTS, DPPH and FRAP) and microbial growth. The addition of turmeric powder modified the meat color, produced an antioxidant capacity similar to ascorbic acid and determined a lower cooking loss than other formulations. Turmeric powder might be considered as a useful natural antioxidant, increasing the quality and extending the shelf life of rabbit burgers.

Topics: Animals; Antioxidants; Ascorbic Acid; Benzothiazoles; Biphenyl Compounds; Color; Cooking; Curcuma; Food Handling; Food Preservation; Food Preservatives; Food Storage; Humans; Meat; Meat Products; Picrates; Plant Extracts; Powders; Rabbits; Sulfonic Acids; Thiobarbituric Acid Reactive Substances; Water

This research aimed to compare antioxidant and anticancer activities of the essential oil from various habitats of Selaginella doederleinii Hieron. The results showed that antioxidative activities of the essential oil were the best from Guizhou province in 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, 2,2'-azinobis-(3-ethylbenzthiazoline-6-sulphonate) (ABTS) radical scavenging, ferric reducing and ferric reducing antioxidant power (FRAP), while those of the essential oil from Sichuan province were the weakest among different habitats. The anticancer results showed that antitumor effects of the essential oil from Guizhou province were the best against A549 cell line and 7721 cell line, while those of the essential oil from Sichuan province were the weakest among different habitats. Proliferative and antioxidant activities were correlated. The correlation coefficients (R2) between antioxidant and anticancer capacities varied from 0.71 to 0.94. The results of tests indicated that the antioxidant and anticancer activities of the essential oil from various habitats were great differences that might be affected by environmental variation, harvest seasons and so on. Investigation in vitro revealed that the essential oil of S. doederleinii were found to be effective in suppressing the oxidative activity and proliferation of cancer cells. This experiment provides scientific foundation for further utilization of S. doederleinii.

Topics: Antineoplastic Agents; Antioxidants; Ascorbic Acid; Benzothiazoles; Biphenyl Compounds; Butylated Hydroxytoluene; Cell Line, Tumor; Cell Proliferation; Cisplatin; Ecosystem; Humans; Oils, Volatile; Picrates; Selaginellaceae; Sulfonic Acids; Tetrazolium Salts; Thiazoles

A variety of bis heterocycles, oxazolyl/thiazolyl/imidazolyl oxadiazoles having a styryl sulfonylmethyl group at the 5-position of oxadiazole and tris heterocycles having a pyrrolyl/pyrazolyl sulfonylmethyl group at the 5-position of oxadiazole were prepared adopting simple and versatile synthetic methodologies. All the compounds were screened for their antioxidant activities. Compound 5b displayed radical scavenging activity in all the three methods greater than the standard ascorbic acid, whereas compounds 8b and 14b showed activities equal to the standard ascorbic acid.

Topics: Ascorbic Acid; Benzothiazoles; Biphenyl Compounds; Drug Design; Free Radical Scavengers; Heterocyclic Compounds; Molecular Structure; Nitric Oxide; Picrates; Structure-Activity Relationship; Sulfonic Acids

Loess Plateau is a typical rain-fed farming region, facing the threat of drought. Irrigation method is among the most important factors affecting jujube quality. This study investigated the response of Ziziphus jujuba Mill. cv. Lizao quality to three different irrigation methods (drip-, pipe- and surge spring root irrigation) combining two water levels (20 m(3)/hm(2) and 120 m(3)/hm(2)). The effects of the trials were evaluated by taking into account the physical-chemical characteristics of jujubes and the antioxidant activity. Concomitant to this, the concentration of some taste-related (viz. glucose, fructose, TSS and malic acid) and health-related compounds/parameters (viz. catechin and epicatechin) were generally much greater in jujube fruit treated with drip irrigation (120 m(3)/hm(2)). Different irrigation treatments had no significant effects on antioxidant capacity, total phenolics and proanthocyanidins (except for pipe irrigation 20 m(3)/hm(2)). The best compromise between quality and irrigation of jujube fruit was achieved with drip irrigation (120 m(3)/hm(2)).

Topics: Agricultural Irrigation; Antioxidants; Ascorbic Acid; Benzothiazoles; Biomass; Biphenyl Compounds; Carbohydrates; Carboxylic Acids; China; Ecosystem; Fruit; Humidity; Phenols; Picrates; Plant Roots; Proanthocyanidins; Solubility; Sulfonic Acids; Water Supply; Ziziphus

The chelation behavior of N-{[(allylamino) thiomethyl] hydrazinocarbonylmethyl} trimethylammonium chloride (H3ATHC) towards VO(2+), Co(2+), Ni(2+), Cu(2+), Zn(2+) and UO2(2+) ions have been studied. The structures of the complexes were elucidated using elemental analyses, spectral (IR, UV-visible, (1)H NMR and ESR and mass) as well as magnetic and thermal measurements. The ligand acted as ON bidentate, ONS tridentate donor forming mononuclear complexes. A tetrahedral geometry for Co(2+), square-planar for Ni(2+) and Cu(2+), an octahedral for Zn(2+) and a square-pyramidal arrangement for VO(2+) complexes were proposed, respectively. The EPR spectra of Cu(2+) and VO(2+) complexes confirmed the suggested geometries with values of α(2) and β(2) indicating that the in-plane σ-bonding and in-plane π-bonding are appreciably covalent, and were consistent with very strong in-plane σ bonding in the complexes. Also, the bond length, bond angle, HOMO, LUMO, dipole moment and charges on the atoms have been calculated. Also, the thermal behavior and kinetic parameters were determined using Coats-Redfern and Horowitz-Metzger methods. Furthermore, the synthesized compounds were screened for their superoxide-scavenging activity in the PMS/NADH-NBT system as well as their scavenging effect on ABTS (2,2'-azino-bis(3-ethyl benzthiazoline-6-sulfonic acid) and 2,2-diphenyl-1-picrylhydrazyl(DPPH) radicals. Among these compounds, the ligand and Zn(2+) complex, exhibited the potent ABTS (2,2'-azino-bis(3-ethyl benzthiazoline-6-sulfonic acid) radical scavenging activity, comparable to that of vitamin C.

Topics: Antioxidants; Ascorbic Acid; Benzothiazoles; Biphenyl Compounds; Cations, Divalent; Metals; Models, Chemical; Models, Molecular; Picrates; Semicarbazides; Sulfonic Acids

From the n-BuOH-soluble fraction of a MeOH extract of the fruits of Rosa soulieana, one new phenolic glucoside (1) was isolated along with five known compounds, comprising two lignin glycosides, two flavonoid glycosides and a phenolic glycoside. The chemical structure of the new compound was elucidated by extensive spectroscopic analyses, including ESI-MS, UV, IR, (1)H and (13)C NMR, DEPT and 2D NMR (HSQC and HMBC). All the isolated compounds were evaluated for their antioxidant activity by using ABTS (2,2'-azino-bis(3-ethylbenzoline-6-sulfonic acid)) assay. Among these compounds, 1, 3 and 6 exhibited strong scavenging activity in ABTS(·+)(SC50 = 102.10, 193.85, 65.38 μmol/L, respectively) compared with the positive control l-ascorbic acid (Vc) (SC50 = 117.16 μmol/L).

Topics: Ascorbic Acid; Benzothiazoles; Drugs, Chinese Herbal; Fruit; Glycosides; Hydroxybenzoates; Molecular Structure; Nuclear Magnetic Resonance, Biomolecular; Rosa; Sulfonic Acids

In the present study the structure of proanthocyanidins from Polyalthia longifolia leaves was characterized with (13)C nuclear magnetic resonance, high performance liquid chromatography electrospray ionization mass spectrometry, and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry analyses. The results showed that the proanthocyanidins were mixture of homopolymers of B-type procyanidins with degree of polymerization up to 14-mer. Furthermore, the antioxidant activity of the proanthocyanidins was studied through 2,2-diphenyl-1-picrylhydrazyl and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) free-radical scavenging activities, and ferric reducing/antioxidant power assays. In addition, antityrosinase activity of the proanthocyanidins was investigated. The IC50 for 2,2-diphenyl-1-picrylhydrazyl and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) free-radical scavenging activity of the proanthocyanidins were 89.32 ± 12.07 and 76.79 ± 5.88 μg/mL, respectively; the ferric reducing/antioxidant power value was 710.54 ± 142.82 mg ascorbic acid equivalent/g dry weight. The IC50 for antityrosinase activity was 773.09 ± 1.47 μg/mL. In conclusion, the proanthocyanidins from P. longifolia leaves exhibited potent antioxidant and antityrosinase activities. This research would provide scientific evidence for the use of proanthocyanidins from P. longifolia leaves as antioxidant and antityrosinase agents.

Topics: Antioxidants; Ascorbic Acid; Benzothiazoles; Biflavonoids; Biphenyl Compounds; Catechin; Chromatography, High Pressure Liquid; Enzyme Inhibitors; Free Radical Scavengers; Inhibitory Concentration 50; Magnetic Resonance Spectroscopy; Monophenol Monooxygenase; Oxidation-Reduction; Picrates; Plant Leaves; Polyalthia; Proanthocyanidins; Reducing Agents; Spectrometry, Mass, Electrospray Ionization; Sulfonic Acids

In this study, we evaluated total phenolics, condensed tannins, ascorbic acid, lycopene, β-carotene, total antioxidant activity, reducing power, ferric-reducing antioxidant power, and radical scavenging activity (RSA) on ABTS and DPPH as well as metal chelating activity of methanolic and aqueous extract from caps and stipes of Calocybe indica and Pleurotus sajor-caju mushrooms. Per gram of extract, the different mushroom extracts contained 18.09-27.47 mg gallic acid equivalent of phenolics, 5.06-8.89 mg catechins of tannins, and 0.15-0.21 mg ascorbic acid. Principal component analysis (PCA) revealed that methanolic extract from caps of C. indica and P. sajor-caju contained higher ascorbic acid, total antioxidant activity, β-carotene and radical scavenging activity (RSA) on 2,2-diphenyl-1-picrylhydrazyl (DPPH) than did the stipes. The aqueous extract from cap and stipe of P. sajor-caju had higher total phenolics and RSA on 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) as well as higher metal-chelating activity and ferric-reducing antioxidant power. The antioxidant potential is higher in the caps of P. sajor-caju and C. indica than in the stipes; the cap contributes most to antioxidant activity.

Topics: Antioxidants; Ascorbic Acid; Basidiomycota; Benzothiazoles; beta Carotene; Biphenyl Compounds; Carotenoids; Chelating Agents; Fluorescence Recovery After Photobleaching; India; Lycopene; Picrates; Polyphenols; Sulfonic Acids; Tannins

An 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS)-immobilized carbon nanotube (CNT) electrode was used to simultaneously detect dopamine (DA) and uric acid (UA) in the presence of ascorbic acid (AA) with differential pulse voltammetry. When ABTS was immobilized onto the CNT electrode in the presence of DA, UA and 100 μM AA, the sensitivity to DA increased from 0.600 (±0.013) to 1.334 (±0.010) μA/μM in the concentration ranges of 0.90-10 μM and 1.87-20 μM, respectively, and the sensitivity to UA increased from 0.030 (±0.005) to 0.078 (±0.006) μA/μM in the concentration ranges of 2.16-240 μM and 3.07-400 μM, respectively. These findings demonstrate that the ABTS-immobilized CNT electrode attained a higher sensitivity to UA and also a wider linear range of concentrations.

Topics: Ascorbic Acid; Benzothiazoles; Dielectric Spectroscopy; Dopamine; Dopamine Agents; Electrochemical Techniques; Electrodes; Humans; Nanotubes, Carbon; Sensitivity and Specificity; Sulfonic Acids; Uric Acid

A new class of acetamidomethylsulfonyl bis heterocycles-oxazolyl-1,3,4-oxadiazoles, -thiazolyl-1,3,4-oxadiazoles, and -imidazolyl-1,3,4-oxadiazoles were synthesized from the synthetic intermediates, methyl 2-((4-aryloxazol-2-ylcarbamoyl)methylsulfonyl)acetate, methyl 2-((4-arylthiazol-2-ylcarbamoyl)methylsulfonyl)acetate, and methyl 2-((4-aryl-1H-imidazol-2-ylcarbamoyl)methylsulfonyl)acetate. All the title compounds were tested for their antioxidant activity. The oxadiazolylmethylsulfonyloxazolylacetamide displayed excellent radical-scavenging activity when compared with the standard ascorbic acid.

Topics: Antioxidants; Ascorbic Acid; Benzothiazoles; Biphenyl Compounds; Imidazoles; Molecular Structure; Nitric Oxide; Oxadiazoles; Picrates; Structure-Activity Relationship; Sulfonic Acids

A series of pyrazolotriazone derivatives 8-10 were obtained via coupling of 3-(3,5-dimethyl-1H-pyrazol-1-yl)-3-oxopropanenitrile (1) with 3-pyrazole diazonium chlorides 2-4, followed by heating of the formed hydrazones 5-7 in acetic acid, respectively. Moreover, coupling reaction of 1 with the aryl diazonium salts 15a-c afforded hydrazones 16a-c. Furthermore, treatment of 1 with 2-hydroxy-1-aldehydes 18-20 afforded the corresponding coumarins 21-23, respectively. Finally, compound 1 reacted with 1-nitrosonaphthalen-2-ol (26) and 6-amino-5-nitroso-2-thioxo-2,3-dihydropyrimidin-4(1H)-one (28) to give 3-oxo-3H-naphtho[2,1-b][1,4]oxazine-2-carbonitrile (25) and pyridazinopyrimidine (29), respectively. The newly synthesized compounds were screened for their ABTS antioxidant activity. Compounds 7 (90.39%), 10 (85.88%), and 16a (91.95%) exhibited promising activities. The most potent compound, 16a, has the ability to protect DNA from the damage induced by bleomycin.

Topics: Antioxidants; Ascorbic Acid; Benzothiazoles; Bleomycin; Coumarins; DNA Damage; Drug Design; Molecular Structure; Pteridines; Structure-Activity Relationship; Sulfonic Acids; Triazines

p-coumaric acid (4-hydroxycinnamic acid), a phenolic acid, is a hydroxyl derivative of cinnamic acid. It decreases low density lipoprotein (LDL) peroxidation and reduces the risk of stomach cancer. In vitro radical scavenging and antioxidant capacity of p-coumaric acid were clarified using different analytical methodologies such as total antioxidant activity determination by ferric thiocyanate, hydrogen peroxide scavenging, 1,1-diphenyl-2-picryl-hydrazyl free radical (DPPH) scavenging, 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) radical scavenging activity and superoxide anion radical scavenging, ferrous ions (Fe(2+)) chelating activity and ferric ions (Fe(3+)) reducing ability. p-Coumaric acid inhibited 71.2% lipid peroxidation of a linoleic acid emulsion at 45μg/mL concentration. On the other hand, butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), α-tocopherol and ascorbic acid displayed 66.8%, 69.8%, 64.5% and 59.7% inhibition on the peroxidation of linoleic acid emulsion at the same concentration, respectively. In addition, p-coumaric acid had an effective DPPH scavenging, ABTS(+) scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging, ferric ions (Fe(3+)) reducing power and ferrous ions (Fe(2+)) chelating activities. Also, those various antioxidant activities were compared to BHA, BHT, α-tocopherol and ascorbic acid as references antioxidant compounds. These results suggested that p-coumaric acid can be used in the pharmacological and food industry because of these properties.

Topics: alpha-Tocopherol; Antioxidants; Ascorbic Acid; Benzothiazoles; Butylated Hydroxyanisole; Butylated Hydroxytoluene; Chelating Agents; Coumaric Acids; Free Radical Scavengers; Hydrogen Peroxide; Iron; Oxidation-Reduction; Propionates; Reference Standards; Spectrum Analysis; Sulfonic Acids; Superoxides; Thiocyanates

Increasing demand for more jujube (Ziziphus jujube Mill.) production requires understanding the specific fertilization needs of jujube trees. This study was conducted to compare fruit yields, phenolic profiles and antioxidant activity of jujube in response to different fertilizers. Application of organic fertilizer appeared to enhance the phenolics and antioxidant activity accumulation of jujubes, compared to conventional fertilized jujubes. Amongst inorganic fertilizers, supplemental potassium as an individual nutrient improved the accumulation of phenolics in jujubes. Our results demonstrate that phenolics levels and antioxidant activity of jujube can be manipulated through fertilizer management and tracked by following proanthocyanidin concentrations. In a practical production context, the combination of organic fertilizers and inorganic fertilizers such as more supplemental individual potassium, and less supplemental individual nitrogen and phosphorus, might be the best management combination for achieving higher phenolic concentration, stronger antioxidant activity and a good harvest.

Topics: Ascorbic Acid; Benzothiazoles; Biphenyl Compounds; Fertilizers; Flavonoids; Free Radical Scavengers; Free Radicals; Fruit; Oxidation-Reduction; Phenols; Picrates; Proanthocyanidins; Sulfonic Acids; Ziziphus

Hardy kiwifruit (Actinidia arguta) is a new species, commercially grown in recent years. Total phenolics (TPC), vitamin C (TAA) content, antioxidant activity (AA) and their year-to-year variability in seven hardy kiwifruit clones were evaluated. TPC was determined using the Folin-Ciocalteu reagent assay. TAA was estimated by determination of l-ascorbic acid and l-dehydroascorbic acid levels using high-performance liquid chromatography. AA was measured using diphenyl-1-picryl-hydrazyl (DPPH), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and OH radicals.. The highest content of vitamin C, in all seasons, was found in D11 (1447-2181 mg kg(-1) fresh weight) and phenolics for D11 and M1 clones (2583-3312 and 2228-3414 mg gallic acid equivalents kg(-1) fresh weight, respectively). TPC and TAA content showed significant differences between hardy kiwifruit clones and showed significant year-to-year variability. Each year, the level of AA was significantly higher for D11 (DPPH, ABTS). AA was strongly correlated with TPC and TAA content in Actinidia fruit.. Hardy kiwifruit are an important source of vitamin C and phenolics, which resulted in their good antioxidant potential. A significantly higher content of these compounds was found in fruit of hybrid origin, which suggests that A. purpurea × A. arguta clones may be useful genetic resources for further interspecific hybridization.

Topics: Actinidia; Antioxidants; Ascorbic Acid; Benzothiazoles; Biphenyl Compounds; Chimera; Diet; Fruit; Humans; Hydroxyl Radical; Phenols; Picrates; Seasons; Species Specificity; Sulfonic Acids

Twelve Colorado-grown specialty potato clones were evaluated for total phenolic content, antioxidant activity and ascorbic acid content at harvest and after 2, 4, 6 and 7 months cold storage at 4 °C. Potato clones were categorized as pigmented ('CO97226-2R/R', 'CO99364-3R/R', 'CO97215-2P/P', 'CO97216-3P/P', 'CO97227-2P/P', 'CO97222-1R/R', 'Purple Majesty', 'Mountain Rose' and 'All Blue'), yellow ('Yukon Gold') and white fleshed ('Russet Nugget', 'Russet Burbank'). Folin-Ciocalteu reagent was used to estimate total phenolic content, and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS(•+) ) and 2,2-diphenyl-1-picrylhydrazyl (DPPH(•) ) radical scavenging assays were used to estimate antioxidant capacity.. Pigmented potato genotypes had significantly higher total phenolic content and antioxidant activity at all data points than yellow- and white-fleshed cultivars. Vitamin C content was higher in 'Yukon Gold' than in the other clones. The highest level of vitamin C in all clones was at harvest and after 2 months in cold storage. Vitamin C content in all potato clones dropped rapidly with longer intervals of cold storage. Although total phenolic content and antioxidant activity fluctuated during cold storage, after 7 months of cold storage their levels were slightly higher than at harvest. Total phenolic content was better correlated with Trolox equivalent antioxidant capacity (TEAC)/ABTS(•+) than the TEAC/DPPH(•) radical scavenging assay.. Pigmented potato clones had significantly higher total phenolic content and antioxidant activity, while the yellow-fleshed potato cultivar 'Yukon Gold' had significantly higher vitamin C content. Vitamin C content decreased in all potato clones during cold storage, while total phenolics increased in pigmented clones.

Topics: Antioxidants; Ascorbic Acid; Benzothiazoles; Biphenyl Compounds; Cold Temperature; Diet; Food Storage; Humans; Phenols; Picrates; Pigments, Biological; Plant Tubers; Solanum tuberosum; Species Specificity; Sulfonic Acids

The occurrence of three known benzophenones, namely annulatophenonoside, acetylannulatophenonoside and annulatophenone as well as a flavonol O-glycoside guajaverin in the aerial parts of Hypericum maculatum Crantz was established. In addition, hyperoside, isoquercitrin and miquelianin were isolated from this plant, as well. Radical scavenging and antioxidant activities of the isolated compounds were examined using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt (ABTS) free radicals, ferric reducing antioxidant power (FRAP) assay and inhibition of lipid peroxidation in linoleic acid system by the ferric thiocyanate method. Isoquercitrin demonstrates the highest DPPH radical scavenging (96.6 ± 0.3%), FRAP (23.8 ± 0.2 Trolox equivalent, TE mol⁻¹) and antioxidant activity in linoleic acid system. Guajaverin and acetylannulatophenonoside show significantly strong ABTS radical scavenging activity (93.9 ± 0.4% and 93.4 ± 0.6%, respectively), which is comparable to that of ascorbic acid (96.2 ± 0.4%).

Topics: Antioxidants; Ascorbic Acid; Benzophenones; Benzothiazoles; Biphenyl Compounds; Flavonoids; Hypericum; Picrates; Sulfonic Acids

The aim of this study was to evaluate the in vitro antioxidant potential of hydro-ethanolic extract of a novel phytococktail comprising of sea buckthorn, apricot, and Rhodiola (SAR) from trans-Himalaya. The 1,1-diphenyl-2-picrylhydrazyl (DPPH) activity of the extract increased in a dose-dependent manner (upto 0.1 mg/mL), and was found to be about 38% of that of ascorbic acid at 0.1 mg/mL. The hydro-ethanolic extract of SAR also scavenged the ABTS(.+) radical generated by ABTS/potassium persulfate (PPS) system and was found to be about 62% of that of ascorbic acid at 0.1 mg/ mL. The total antioxidant power of the extract was determined by ferric reducing antioxidant power (FRAP) assay. Total phenolic content was found to be 1.28016 × 10(-3) mol gallic acid equivalent (GAE)/g extract. Total flavonoid and flavonol contents were estimated to be 2.5970 × 10(-4) mol and 4.87 × 10(-4) mol quercetin equivalent/g extract, respectively. The hydro-ethanolic extract of this phytococktail indicated presence of essential phytoconstituents of polyphenols, flavonoids, flavonols, and ascorbic acid, which contributed significantly to its antioxidant capacity. The combination of the 3 plants may well support their use in traditional medicine to combat oxidative stress and high-altitude sickness.

Topics: Antioxidants; Ascorbic Acid; Benzothiazoles; Ethanol; Fruit; Gallic Acid; Hippophae; Plant Extracts; Polyphenols; Prunus; Rhodiola; Sulfonic Acids

In this study, leaves of three indigenous varieties of Mulberry namely, Morus alba L., Morus nigra L. and Morus rubra L. were investigated for their antioxidant potential and their proximate composition was determined. The yields of 80% methanolic extracts ranged between 8.28-13.89%. The contents of total phenolics (TPC), total flavonoids (TFC) and ascorbic acid (AA) ranged between 16.21-24.37 mg gallic acid equivalent (GAE)/g, 26.41-31.28 mg rutin equivalent (RE)/g and 0.97-1.49 mg/g, respectively. The antioxidant activity of leaf extracts was evaluated by measuring 1,1-diphenyl-2-picrylhydrazyl (DPPH(•)) radical scavenging actity, 2,2'-azino-bis-(3-ethylbenzthiazoline-6-sulphonic acid (ABTS(•+)) radical cation scavenging capacity and ferric ion reducing power and values ranged between 1.89-2.12, 6.12-9.89 and 0.56-0.97 mM Trolox equivalent/g of dried leaves, respectively. The investigated features reveal good nutritive and antioxidant attributes of all the varieties with mutually significant differences.

Topics: Antioxidants; Ascorbic Acid; Benzothiazoles; Biphenyl Compounds; Cations; Flavonoids; Free Radical Scavengers; Free Radicals; Lipids; Methanol; Morus; Phenol; Phenols; Picrates; Plant Extracts; Plant Leaves; Rutin; Species Specificity; Sulfonic Acids

In the present study, antioxidant properties of flavonoids and polysaccharides from tobacco (Nicotiana tabacum L.) leaves were evaluated in several in vitro systems, e.g., scavenging activities on hydroxyl, superoxide anion, 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) radicals, and reducing power. Flavonoids showed much better activity than polysaccharides in scavenging activities on free radicals. When compared to the positive control, ascorbic acid, both showed weaker antioxidant potential. However, flavonoids possessed comparable superoxide anion, DPPH and ABTS radical scavenging abilities to ascorbic acid at high concentration (600 μg/mL). Meanwhile, it was found that flavonoids had prominent effects on the reducing power, which was equivalent to ascorbic acid, and was significantly higher than polysaccharides. These results clearly indicate that flavonoids are effective in scavenging free radicals and have the potential to be powerful antioxidants. Thus, tobacco leaves could be considered as a potential source of natural antioxidants for food, pharmaceutical, cosmetics or nutraceutical industries.

Topics: Antioxidants; Ascorbic Acid; Benzothiazoles; Biphenyl Compounds; Flavonoids; Free Radical Scavengers; Free Radicals; Hydroxyl Radical; Nicotiana; Oxidation-Reduction; Picrates; Plant Extracts; Plant Leaves; Polysaccharides; Sulfonic Acids; Superoxides

Three new diterpenes Amijiol acetate (3), dolabellane, Dolabellatrienol (4), and dolastane, Amijiol-7, 10-diacetate (9) were isolated together with the previously described Pachydictyol A (1), Isopachydictyol A (2), 8β-hydroxypachydictyol A (5), Amijiol (6), Isodictyohemiacetal (7) and Dictyol C (8) from the Red Sea brown alga Dictyota dichotoma var. implexa. The structures and relative stereochemistry of the new diterpenoids were proposed on the basis of their spectral data. Compounds 3 and 9 have potent activity against DNA damage, cytotoxicity against WI-38, HepG2, and MCF-7 cell lines, and antioxidant using ABTS and erythrocytes hemolysis.

Topics: Animals; Antineoplastic Agents; Antioxidants; Benzothiazoles; Cell Line, Tumor; Cell Survival; Chlorocebus aethiops; Diterpenes; DNA Damage; Erythrocytes; Hemolysis; Humans; Phaeophyceae; Sulfonic Acids; Vero Cells

4-Schiff base-7-benzyloxy-coumarins 5a(1)-5h(2) and its derivative 6 were designed and synthesized based on the 7-benzyloxy-coumarin structure as novel antioxidants. The in vitro antioxidant activities screening revealed that 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activities of compounds 5b(1), 5d(1), 5f(1), 5f(2), 5g(1) and 5g(2), and 2,2'-azinobis-(3-ethylbenzthiazoline-6-sulfonate) cation (ABTS(+)) radical scavenging activities of compounds 5a(1), 5b(1), 5c(1), 5c(2), 5d(1), 5e(1), 5e(2), 5f(2), 5g(1), 5g(2) and 5h(1) were better than that of the commercial antioxidant butylated hydroxytoluene (BHT), while the superoxide anion radical scavenging activities of 5a(2) and 5g(2) were stronger than that of the commercial antioxidant butylated hydroxyanisole (BHA), and the hydroxyl radical scavenging activity of 5e(1) was much better than that of the common antioxidant ascorbic acid.

Topics: Benzothiazoles; Biphenyl Compounds; Coumarins; Free Radical Scavengers; Free Radicals; Picrates; Schiff Bases; Sulfonic Acids; Superoxides; Thiazoles

Vanillin, a compound widely used in foods, beverages, cosmetics and drugs, has been reported to exhibit multifunctional effects such as antimutagenic, antiangiogenetic, anti-colitis, anti-sickling, and antianalgesic effects. However, results of studies on the antioxidant activity of vanillin are not consistent.. We systematically evaluated the antioxidant activity of vanillin using multiple assay systems. DPPH radical-, galvinoxyl radical-, and ABTS(+)-scavenging assays, ORAC assay and an oxidative hemolysis inhibition assay (OxHLIA) were used for determining the antioxidant activity.. Vanillin showed stronger activity than did ascorbic acid and Trolox in the ABTS(+)-scavenging assay but showed no activity in the DPPH radical- and galvinoxyl radical-scavenging assays. Vanillin showed much stronger antioxidant activity than did ascorbic acid and Trolox in the ORAC assay and OxHLIA. In the ABTS(+)-scavenging assay, ORAC assay and OxHLIA, vanillin reacted with radicals via a self-dimerization mechanism. The dimerization contributed to the high reaction stoichiometry against ABTS(+) and AAPH-derived radicals to result in the strong effect of vanillin. Oral administration of vanillin to mice increased the vanillin concentration and the antioxidant activity in plasma. These data suggested that antioxidant activity of vanillin might be more beneficial than has been thought for daily health care.. Based on the results of the present study, we propose the addition of antioxidant capacity to the multifunctionality of vanillin.

Topics: Animals; Antioxidants; Ascorbic Acid; Benzaldehydes; Benzhydryl Compounds; Benzothiazoles; Biphenyl Compounds; Chromans; Chromatography, High Pressure Liquid; Dose-Response Relationship, Drug; Drug Evaluation, Preclinical; Erythrocytes; Free Radical Scavengers; Hemolysis; Mice; Molecular Structure; Oxidation-Reduction; Picrates; Sheep; Sulfonic Acids

A semiquinone glucoside derivative (SQGD) was isolated from a radioresistant bacterium Bacillus sp. INM-1 and its antioxidant and radioprotective activities were evaluated using in vitro assays. Natural stable free radical properties of SQGD in solid as well as in solution form were estimated using Electron Paramagnetic Resonance (EPR) spectrometry. Results of the study were demonstrated high reducing power (1.267 ± 0.03356 U(abs)) and nitric oxide radicals scavenging activity (34.684 ± 2.132%) of SQGD. Maximum lipid peroxidation inhibitory activity of SQGD was found to be 74.09 ± 0.08% at 500 μg/ml concentration. Similarly, significant (39.54%; P < 0.05) protection to the liposomal artificial membrane against gamma radiation was observed by SQGD in terms of neutralization of gamma radiation-induced TBARS radicals in vitro. OH(-) radicals scavenging efficacy of SQGD was estimated in terms of % inhibition in deoxy D: -ribose degradation by non-site-specific and site-specific assay. The maximum (54.01 ± 1.01%) inhibition of deoxy D: -ribose degradation was observed in non-site-specific manner, whereas, site-specific inhibition was observed to be 46.36 ± 0.5% at the same concentration (250 μg/ml) of SQGD. EPR spectroscopic analysis of the SQGD indicated ~80% reduction of DPPH radicals at 6.4% concentration. EPR spectral analysis of SQGD was revealed an appearance of very strong EPR signal of 2.00485 (crystalline form) and 2.00520 (solution form) g(y) tensor value, which were an established characteristic of o-semiquinone radicals. Therefore, it can be concluded that SQGD is a natural stable o-semiquinone-type radical, possessing strong antioxidant activities and can effectively neutralize radiation induced free radicals in biological system.

Topics: Antioxidants; Ascorbic Acid; Bacillus; Benzothiazoles; Biphenyl Compounds; Electron Spin Resonance Spectroscopy; Free Radical Scavengers; Glucosides; Hydroxyl Radical; Lipid Peroxidation; Liposomes; Nitric Oxide; Oxidation-Reduction; Picrates; Radiation-Protective Agents; Sulfonic Acids

This study reports the antioxidant and antibacterial activities of four fresh mango seed extracts from Thai varieties. Total phenol contents determined by the Folin-ciocalteu method revealed the highest values to be in MKE, Chok-a-nan variety (399.8 mgGAE/g extract) and MSE of Nam-dok-mai variety (377.2 mgGAE/g extract). Both extracts showed potent ABTS˙+ radical and DPPH˙ radical scavenging activities with the lower half inhibition concentration (IC50) values than those of the reference compounds; vitamin C, trolox and BHA, respectively. Their antioxidant property of MSE and MKE is strongly correlated with the total phenol contents (r=0.98 and 0.98, respectively). When combined the MSE and MKE of the Fah-lun variety showed the strongest antioxidant activity. All mango seed extracts showed interesting antibacterial activity against both gram positive and gram negative bacteria as determined by disc diffusion method. The most sensitive pathogenic strain inhibited by all extracts (especially Kaew variety) was Pseudomonas aeruginosa ATCC 27853. This work suggests potential applications for practical uses of mango seed extracts from Thai varieties, as sources of antioxidant and antibacterial agents.

Topics: Anti-Bacterial Agents; Antioxidants; Ascorbic Acid; Bacteria; Benzothiazoles; Biphenyl Compounds; Chromans; Diffusion; Free Radical Scavengers; Indicators and Reagents; Mangifera; Microbial Sensitivity Tests; Phenols; Picrates; Plant Extracts; Seeds; Sulfonic Acids; Thailand

The phytochemical composition of carotenoids, tocopherols, free sugars, organic acids, L-ascorbic acid, capsaicinoids, and flavonoids in green and red paprika (GP and RP), and paprika leaves (PL) cultivated in Korea were analyzed. The ethanolic extracts of GP, RP, and PL were obtained with 80% ethanol, and their antioxidative activities were determined by measuring their ABTS and DPPH radical scavenging activities. RP showed the highest contents of capsanthin (58.33 ± 3.91 mg/100 g dry weight) and L-ascorbic acid (1987.25 ± 19.64 mg/100 g dry weight), and main compounds of PL were lutein, chlorophyll, and γ-tocopherol (96.91 ± 14.58, 2136.71 ± 21.11, and 723.49 ± 54.10 mg/100 g dry weight, respectively). RP showed the strongest antioxidant activity (IC(50) = 55.23 ± 6.77 μg/mL in a 2, 2'-azino-di-[3-ethylbenzthiazoline sulphonate] assay and 150.40 ± 8.07 μg/mL in a 2, 2-diphenyl-2-picrylhydrazyl assay), and the antioxidant activity of PL was higher than β-carotene but lower than RP. The results indicate that the amounts of capsanthin and L-ascorbic acid in RP correlate well with antioxidant activity. PL, which has various phytochemicals such as lutein, chlorophyll, and γ-tocopherol, might be used in nutraceuticals and pharmaceuticals for improving human health.

Topics: Antioxidants; Ascorbic Acid; Benzothiazoles; Biphenyl Compounds; Capsicum; Carotenoids; Chlorophyll; Flavonoids; Fruit; gamma-Tocopherol; Lutein; Picrates; Plant Leaves; Republic of Korea; Sulfonic Acids; Xanthophylls

The antibrowning and antimicrobial activities of the water-soluble extract from pine needles of Cedrus deodara (CDE), a traditional Chinese medicine and raw materials of pine needle tea, was investigated. Total phenols of CDE were 31.4 ± 0.53 mg gallic acid equivalent/g, and total flavonoids were 23.1 ± 0.79 mg rutin equivalent/g. CDE showed a strong antioxidant activity against ABTS free radicals with IC(50) (the half-inhibitory concentration) of 25.5 ± 0.64 μg/mL. In mushroom tyrosinase inhibitory assay, IC(50) values were 2.1 ± 0.98 and 2.27 ± 0.93 mg/mL for monophenolase and diphenolase, respectively. Evaluated by detecting changes of L* (indicated the darkness of sample), a* (indicated the redness of sample), and b* (indicated the yellowness of sample) values in fresh-cut apple slices model, CDE showed a significant antibrowning effect when compared with ascorbic acid. In addition, it was discovered that CDE in combination with 0.5% ascorbic acid exhibited a synergistic antibrowning effect. Meanwhile, CDE was observed to show a potent antimicrobial effect on all of the tested Gram-positive and Gram-negative bacteria. In conclusion, the results of the present research suggested that pine needles of C. deodara could be used as a natural resource of antibrowning and antimicrobial agents in food preservation.. The present study provides a theoretical basis for the potential application of pine needles of C. deodara to be used as a natural resource of antibrowning and antimicrobial agents in food industry.

Topics: Anti-Infective Agents; Antioxidants; Ascorbic Acid; Benzothiazoles; Cedrus; Flavonoids; Food Preservation; Free Radical Scavengers; Fruit; Gallic Acid; Gram-Negative Bacteria; Gram-Positive Bacteria; Inhibitory Concentration 50; Maillard Reaction; Malus; Medicine, Chinese Traditional; Monophenol Monooxygenase; Oxidoreductases; Phenols; Plant Extracts; Solubility; Sulfonic Acids

Cellular damage induced by free-radicals like Reactive Oxygen and Nitrogen Species (ROS and RNS) has been implicated in several disorders and diseases, including ageing. Hence naturally occurring anti-oxidant rich-herbs play a vital role in combating these conditions. The present study was carried out to investigate the in vitro free-radical quenching capacity of a known Ayurvedic poly-herbal formulation called Vayasthapana Rasayana.. Methanol extracts of Vayasthapana Rasayana formulation (VRF) were studied for in vitro total antioxidant activity along with phenolic content and reducing power. In vitro assays like DPPH, FRAP, ABTS scavenging to evaluate radical quenching potential were performed.. The formulation has shown 94% at 0.1 mg/ml DPPH free-radical scavenging activity as against 84% at 0.1 mg/ml for standard ascorbic acid (IC₅₀ value 5.51 μg/ml for VRF and 39 μg/ml for standard). It has a significant higher ferric reducing potential also (OD 0.87 at 700 nm & 0.21 at 0.1 mg/ml for VRF and standard, respectively). The total phenolic content (gallic acid equivalent) of the VRF is 8.3 mg per g of dry mass. Total antioxidant capacity of the formulation, estimated by FRAP was 1150 ± 5 μM Fe(II)/g dry mass. ABTS radical scavenging activity of VRF was 69.55 ± 0.21% at 100 μg/ml concentration with a IC50 value of 69.87 μg/ml as against 9% and 95% by ascorbic acid and Trolox (at 70.452 μg/ml and 0.250 μg/ml concentrations, respectively).. In Indian traditional Ayurvedic system, use of VRF is in regular practice for mainly combating age-related disorders and diseases as many of the components of the Rasayana are known for their free-radical scavenging activity. This study has validated the potential use of VRF as an anti-oxidant to fight age-related problems.

Topics: Aging; Antioxidants; Ascorbic Acid; Benzothiazoles; Biphenyl Compounds; Chromans; Ferric Compounds; Humans; Magnoliopsida; Medicine, Ayurvedic; Oxidative Stress; Phenols; Picrates; Plant Extracts; Reference Standards; Sulfonic Acids; Thiazoles

The extraction conditions of polysaccharides from Plantago asiatica L. seeds were investigated. Four parameters affecting the polysaccharides extraction, extraction times, water to sample, extraction temperature and single extraction time, were determined by orthogonal experiments. Under the optimized conditions, the polysaccharides yield of P. asiatica L. seeds was 2.467%. The antioxidant activities of the polysaccharides were investigated. The reducing power of the polysaccharides was dose dependent, and the reducing capacity of the polysaccharides was inferior to butylated hydroxytoluene, which is known to be a strong reducing agent. The scavenging rates of the polysaccharides on superoxide and 1,1-diphenyl-2-picrylhydrazyl radicals were 79.7% and 81.4%, at polysaccharides concentration of 0.75 mg/mL, respectively, a scavenging rates approximately similar to that of 0.75 mg/mL ascorbic acid (83.5% and 85.1%, respectively). Furthermore, it exhibited a moderate concentration-dependent ABTS radical scavenging activity, ferrous ion chelating potency and H(2)O(2) scavenging activity. The data obtained in the in vitro models clearly establish the antioxidant potency of the polysaccharides extracted from Semen Plantaginis.

Topics: Antioxidants; Ascorbic Acid; Benzothiazoles; Biphenyl Compounds; Butylated Hydroxytoluene; Chelating Agents; Chemical Fractionation; Edetic Acid; Free Radical Scavengers; Hydrogen Peroxide; Oxidation-Reduction; Picrates; Plantago; Polysaccharides; Seeds; Sulfonic Acids; Superoxides

Oxidative damage is important in the pathogenesis of respiratory distress syndrome (RDS). However, data on the effect of surfactant therapy on oxidative stress in vivo are limited. We aimed to evaluate the oxidant/antioxidant status in preterm infants with RDS via measurement of total antioxidant capacity (TAC) and total oxidant status (TOS), to determine the effect of surfactant on oxidant/antioxidant balance and to assess the association between TAC, TOS and clinical outcomes of the patients.. Sixty-nine infants with RDS were included. Blood samples for determining TAC and TOS were collected before and 48 h after surfactant treatment. TAC and TOS levels were analysed in serum. Patients were followed up until discharge or death.. Post-surfactant TAC levels were significantly higher than pre-surfactant TAC levels (P = 0.029). TAC/TOS ratio significantly increased after surfactant treatment (P = 0.018). Infants <28 weeks of gestational age had lower levels of baseline TAC than those ≥28 weeks of gestational age (P = 0.020), whereas TOS levels were similar. Baseline TAC/TOS ratio was lower in infants who died in the study period than those who survived (P = 0.023). After controlling gestational age, baseline TAC levels were significantly and inversely correlated with the duration of total respiratory support (r = -0.343; P = 0.009) and hospitalization (r = -0.341; P = 0.009). TAC or TOS levels were not associated with the development of bronchopulmonary dysplasia or other complications as determined during the investigation period.. Oxidant-antioxidant balance shifts in favour of the antioxidant system after surfactant treatment. Lower TAC/TOS ratio in preterm infants may be associated with increased mortality.

Topics: Adult; Antioxidants; Ascorbic Acid; Benzothiazoles; Bilirubin; Biological Products; Female; Glutathione; Humans; Hydrogen Peroxide; Infant, Newborn; Infant, Premature; Lipid Peroxides; Male; Oxidative Stress; Phospholipids; Pregnancy; Pulmonary Surfactants; Respiratory Distress Syndrome, Newborn; Sulfonic Acids; Treatment Outcome; Uric Acid; Vitamin E; Young Adult

The present study was undertaken to determine the optimum effective dose, dose reduction factor (DRF) and possible mechanism of action of Aloe gel. Three different doses of gel (250, 500 and 750 mg/kg body weight) were tested against 8 Gy induced damage in Swiss albino mice. A dose of 750 mg/kg body weight of Aloe was found the most effective while, 250 mg/kg body weight was the least effective in providing protection, as observed in the form of higher concentrations of blood GSH and vitamin C and lower level of serum LPO than irradiated animals at 1h post irradiation and higher percent of survivors up to day 30 post irradiation. Treatment of mice with Aloe before irradiation with different doses of gamma radiation (6-12 Gy) delayed the onset and reduced the severity of signs of radiation sickness. The LD(50/30) was calculated as 6.77 and 10 Gy for untreated irradiated and Aloe treated irradiated animals, respectively and its dose reduction factor was also calculated as 1.47. Aloe gel scavenged the free radicals, DPPH•, ABTS(+•) and NO in a concentration dependent manner in vitro and therefore, scavenging of free radicals seems to be its important mechanism of action.

Topics: Aloe; Animals; Antioxidants; Ascorbic Acid; Benzothiazoles; Biphenyl Compounds; Dose-Response Relationship, Drug; Free Radical Scavengers; Gels; Glutathione; Lethal Dose 50; Lipid Peroxidation; Male; Mice; Nitric Oxide; Picrates; Radiation Injuries; Radiation-Protective Agents; Sulfonic Acids

Ramalin (γ-glutamyl-N'-(2-hydroxyphenyl)hydrazide), a novel compound, was isolated from the methanol-water extract of the Antarctic lichen Ramalina terebrata by several chromatographic methods. The molecular structure of ramalin was determined by spectroscopic analysis. The experimental data showed that ramalin was five times more potent than commercial butylated hydroxyanisole (BHA) in scavenging 1-diphenyl-2-picryl-hydazil (DPPH) free radicals, 27 times more potent in scavenging 2,2'-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid free radicals (ABTS(+)) than the vitamin E analogue, trolox, and 2.5 times more potent than BHT in reducing Fe(3+) to Fe(2+) ions. Similarly, ramalin was 1.2 times more potent than ascorbic acid in scavenging superoxide radicals and 1.25 times more potent than commercial kojic acid in inhibiting tyrosinase enzyme activity, which ultimately leads to whitening of skin cells. Ramalin showed no or very little cytotoxicity in human keratinocyte and fibroblast cells at its antioxidant concentration. Furthermore, ramalin was assessed to determine its antioxidant activity in vivo. One microgram per milliliter ramalin significantly reduced the released nitric oxide (NO) and 0.125 μg/ml ramalin reduced the produced hydrogen peroxide (H(2)O(2)) in LPS (lipopolysaccharide)-stimulated murine macrophage Raw264.7 cells. Considering all the data together, ramalin can be a strong therapeutic candidate for controlling oxidative stress in cells.

Topics: Animals; Antarctic Regions; Antioxidants; Ascorbic Acid; Benzothiazoles; Biphenyl Compounds; Butylated Hydroxyanisole; Cell Line; Cell Survival; Chromans; Fibroblasts; Free Radicals; Fungal Proteins; Glutamates; Humans; Hydrogen Peroxide; Keratinocytes; Lichens; Mice; Molecular Structure; Monophenol Monooxygenase; Nitric Oxide; Picrates; Pyrones; Sulfonic Acids

Many health beneficial functions of dietary ingredients, including antimutagenity and anticarcinogenity, have been discussed in relation to their antioxidant properties. In this study, antioxidative mechanisms of whole-apple antioxidants (from seven varieties) were investigated using the 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical scavenging capacity assay, the ferric-reducing antioxidant power (FRAP) assay, and the ferrous iron(II) chelating activity assay. Results indicated the ability of primary antioxidants to act as hydrogen or electron donors, with considerable differences depending on variety, with ABTS and FRAP values ranging from 270 to 1,142 mg of vitamin C equivalents/100 g and from 695 to 3,143 μmol of Fe/100 g, respectively. However, varieties did not display measurable chelating activity except for Florina and Graham, exhibiting a weak activity (0.1-0.2 μg of EDTA equivalents/100 g). Correlation analyses showed that polyphenols were major primary antioxidants contributing to antioxidative mechanisms (r>0.99, P<.001), whereas their involvement as secondary antioxidants (i.e., as chelating compounds) was negligible. Our findings further showed that the intake of 100 g of apple fruits can provide antioxidants equivalent to approximately 270-1,140 mg of vitamin C, with highest antioxidant concentrations for the older varieties Grauapfel and Goldparmäne.

Topics: Anthocyanins; Ascorbic Acid; Benzothiazoles; Chelating Agents; Ferrous Compounds; Free Radical Scavengers; Fruit; Iron; Luxembourg; Malus; Oxidative Stress; Plant Extracts; Polyphenols; Sulfonic Acids

Cadmium (Cd) is ubiquitous in the environment and exposure through food and water as well as occupational sources can contribute to a well-defined spectrum of disease. The present study was undertaken to evaluate the role of hesperetin (Hp) in alleviating the Cd induced biochemical changes in rats.. During the experiment, male Wistar rats were injected with Cd 83 mg/kg day) subcutaneously alone or with oral administration of Hp 840 mg/kg day) for 21 days.. In Cd treated rats the levels of plasma lipid peroxidation (LPO) markers: thiobarbituric acid reactive substances (TBARS) and lipid hydroperoxides (LOOH) were significantly increased while the levels of plasma non-enzymatic antioxidants: reduced glutathione (GSH), vitamins C and E were significantly decreased in Cd administered rats. Administration of Hp along with Cd significantly decreased the level of LPO markers with elevation of non-enzymatic antioxidants in plasma. In vitro studies on the effect of Hp on scavenging 1,1-diphenyl-2-picrylhydrazyl (DPPH*), 2,2-azinobis-(3-ethyl-benzothiazoline-6-sulfonic acid) (ABTS+), superoxide anion (O*-), hydroxyl (OH*) radicals and reducing power also confirmed the free radical scavenging and antioxidant activity of Hp. In addition to that, ascorbic acid, butylated hydroxyl toluene was used as the reference antioxidant radical scavenger compounds. Thus, the observed effects are due to the free radical scavenging and antioxidant potential of Hp. Interestingly, among the different concentrations, tested 50 microM of Hp showed the highest antioxidant and free radical scavenging activities when compared to other concentrations.. The result of these findings provides further evidence to the neutraceutical and pharmaceutical potentials of Hp.

Topics: Administration, Oral; Animals; Antioxidants; Ascorbic Acid; Benzothiazoles; Biomarkers; Biphenyl Compounds; Cadmium Chloride; Dose-Response Relationship, Drug; Environmental Pollutants; Glutathione; Hesperidin; Hydroxyl Radical; Injections, Subcutaneous; Lipid Peroxidation; Lipid Peroxides; Male; Oxidative Stress; Picrates; Rats; Rats, Wistar; Sulfonic Acids; Thiobarbituric Acid Reactive Substances; Vitamin E

The raspberry (Rubus idaeus L.) is an economically important berry crop that contains many phenolic compounds with potential health benefits. In this study, important pomological features, including nutrient content and antioxidant properties, of a domesticated and 3 wild (Yayla, Yavuzlar, and Yedigöl) raspberry fruits were evaluated. Also, the amount of total phenolics and flavonoids in lyophilized aqueous extracts of domesticated and wild ecotypes of raspberry fruits were calculated as gallic acid equivalents (GAEs) and quercetin equivalents (QE). The highest phenolic compounds were found in wild Yayla ecotype (26.66 ± 3.26 GAE/mg extract). Whilst, the highest flavonoids were determined in wild Yedigöl ecotype (6.09 ± 1.21 QA/mg extract). The antioxidant activity of lyophilized aqueous extracts of domesticated and wild ecotypes of raspberry fruits were investigated as trolox equivalents using different in vitro assays including DPPH(•), ABTS(•+), DMPD(•+), and O(•-)(2) radical scavenging activities, H(2)O(2) scavenging activity, ferric (Fe(3+)) and cupric ions (Cu(2+)) reducing abilities, ferrous ions (Fe(2+)) chelating activity. In addition, quantitative amounts of caffeic acid, ferulic acid, syringic acid, ellagic acid, quercetin, α-tocopherol, pyrogallol, p-hydroxybenzoic acid, vanillin, p-coumaric acid, gallic acid, and ascorbic acid in lyophilized aqueous extracts of domesticated and wild ecotypes of raspberry fruits were detected by high-performance liquid chromatography and tandem mass spectrometry (LC-MS-MS). The results clearly show that p-coumaric acid is the main phenolic acid responsible for the antioxidant and radical scavenging activity of lyophilized aqueous extracts of domesticated and wild ecotypes of raspberry fruits.

Topics: Antioxidants; Ascorbic Acid; Benzaldehydes; Benzothiazoles; Chromatography, High Pressure Liquid; Coumaric Acids; Ecotype; Ellagic Acid; Fruit; Gallic Acid; Hydrogen Peroxide; Hydroxybenzoates; Plant Extracts; Polyphenols; Propionates; Pyrogallol; Rosaceae; Sulfonic Acids; Tandem Mass Spectrometry

The synthesis of three types of pulvinic acid analogues, using a diversity-oriented strategy starting from a single compound, dimethyl l-tartrate, is described. Lacey-Dieckmann condensation, alcohol dehydration and Suzuki-Miyaura cross-couplings were employed in the course of the analogues syntheses. The evaluation of the antioxidant properties of the 28 synthesized analogues was carried out using antioxidant capacity assays (protection of thymidine and β-carotene) and free radical scavenging assays (DPPH radical and ABTS radical cation). This allowed to assess the relative influence of the groups bonded to the tetronic ring and to the exocyclic double bond on the activity, as well as the importance of this exocyclic double bond. It was shown that the presence of an electron-donating group on the 3-position of the tetronic ring had a beneficial effect. It was shown in several assays that the presence of the exocyclic bond was not crucial to the activity.

Topics: Benzothiazoles; beta Carotene; Biphenyl Compounds; Carboxylic Acids; Free Radical Scavengers; Lactones; Picrates; Sulfonic Acids; Tartrates; Thymidine

Antioxidant and antimelanogenesis activities of protocatechuic acid (1) from Origanum vulgare (oregano) were investigated. The antioxidative capacity of 1 was confirmed from its free-radical-scavenging activities, inhibition of lipid peroxidation, and suppression of reactive oxygen species in H(2)O(2)-induced BNLCL2 cells. The inhibition by 1 of tyrosinase and DOPA oxidase activity and melanin production was possibly related to the down-regulation of melanocortin-1 receptor, microphthalmia-associated transcription factor, tyrosinase, tyrosinase-related proteins-2, and tyrosinase-related proteins-1 expression in α-melanocyte-stimulating hormone-induced B16 cells. After a gel containing 1 was applied to mice, the values of L* slightly increased, and a* and erythema-melanin levels of skin were reduced by comparing the values of untreated control groups, indicating 1 can reduce melanin production. These results suggest that 1 may act as an effective quencher of oxidative attackers with antimelanogenesis properties.

Topics: alpha-MSH; Animals; Antioxidants; Benzothiazoles; Biphenyl Compounds; Drugs, Chinese Herbal; Free Radical Scavengers; Hydroxybenzoates; Melanins; Melanocytes; Mice; Molecular Structure; Monophenol Monooxygenase; Origanum; Picrates; Reactive Oxygen Species; Skin Pigmentation; Sulfonic Acids

Spirulina is a commercial alga well known to contain various antioxidants, especially phycocyanin. Apart from being sold as a nutraceutical, Spirulina is incorporated as a functional ingredient in food products and beverages. Most of the previous reports on antioxidant activity of Spirulina were based on chemical rather than cell-based assays. The primary objective of this study was to assess the antioxidant activity of aqueous extract from Spirulina based on its protective effect against cell death induced by free radicals.. The antioxidant activity of the cold water extract from food-grade Spirulina platensis was assessed using both chemical and cell-based assays. In the cell-based assay, mouse fibroblast cells (3T3) cells were incubated for 1 h in medium containing aqueous extract of Spirulina or vitamin C (positive control) at 25, 125 and 250 μg/mL before the addition of 50 μM 1,1-diphenyl-2-picrylhydrazyl (DPPH) or 3-ethylbenzothiazoline-6-sulfonic acid (ABTS). The cells were incubated for another 24 h before being assessed for cell death due to apoptosis using the Cell Death Detection ELISA Kit. Spectrophotometric assays based on DPPH and ABTS were also used to assess the antioxidant activity of the extract compared to vitamin C and vitamin E (positive controls).. Spirulina extract did not cause cytotoxic effect on 3T3 cells within the range of concentrations tested (0 - 250 μg/mL). The extract reduced significantly (p < 0.05) apoptotic cell death due to DPPH and ABTS by 4 to 5-fold although the activity was less than vitamin C. Based on the DPPH assay, the radical scavenging activity of the extract was higher than phycocyanin and was at least 50% of vitamin C and vitamin E. Based on the ABTS assay, the antioxidant activity of the extract at 50 μmug/mL was as good as vitamin C and vitamin E.. The results showed that aqueous extract of Spirulina has a protective effect against apoptotic cell death due to free radicals. The potential application of incorporating Spirulina into food products and beverages to enhance their antioxidant capacity is worth exploring.

Topics: 3T3 Cells; Animals; Antioxidants; Apoptosis; Ascorbic Acid; Benzothiazoles; Biphenyl Compounds; Enzyme-Linked Immunosorbent Assay; Fibroblasts; Free Radicals; Mice; Oxidative Stress; Phycocyanin; Picrates; Plant Extracts; Spectrophotometry; Spirulina; Sulfonic Acids; Vitamin E

Free radicals play a crucial role in the pathophysiology of human diseases such as cancer, atherosclerosis, and neurodegenerative diseases, and considerable attention has been focused on functional foods (or nutraceuticals) that are able to decrease the concentrations of free radicals and consequently protect against these diseases. The present study investigated an improved quantitative assay to measure antioxidant activity using the stable and fast-reacting chromogenic indicator [2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid)] (ABTS). The ABTS-radical-scavenging activities of various antioxidants and apple extracts were measured in 96-well plates, and plots thereof were linearly interpolated, with the total radical-scavenging capacity quantified as the area under the curve. The first order of linear regression was obtained in a relationship between the absorbance reduction and various concentrations of the tested sample, and the total radical-scavenging capacity was expressed as the vitamin-C-equivalent antioxidant capacity. The advantages of this quantitative assay are that, first, it is fast, sensitive and confers little variation from experimental errors for single or mixed antioxidants; second, a large number of samples in a low quantity at a time can be run using 96-well plates.

Topics: Antioxidants; Ascorbic Acid; Benzothiazoles; Butylated Hydroxyanisole; Chromogenic Compounds; Colorimetry; Food Analysis; Free Radical Scavengers; Humans; Kaempferols; Malus; Plant Extracts; Quercetin; Sulfonic Acids

The antioxidant activity of a provitamin C agent, 2-O-beta-D-glucopyranosyl-L-ascorbic acid (AA-2betaG), was compared to that of 2-O-alpha-D-glucopyranosyl-L-ascorbic acid (AA-2G) and ascorbic acid (AA) using four in vitro methods, 1,1-diphenyl-picrylhydrazyl (DPPH) radical-scavenging assay, 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical cation (ABTS(*+))-scavenging assay, oxygen radical absorbance capacity (ORAC) assay, and 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH)-induced erythrocyte hemolysis inhibition assay. AA-2betaG slowly and continuously scavenged DPPH radicals and ABTS(*+) in roughly the same reaction profiles as AA-2G, whereas AA quenched these radicals immediately. In the ORAC assay and the hemolysis inhibition assay, AA-2betaG showed similar overall activities to AA-2G and to AA, although the reactivity of AA-2betaG against the peroxyl radical generated in both assays was lower than that of AA-2G and AA. These data indicate that AA-2betaG had roughly the same radical-scavenging properties as AA-2G, and a comprehensive in vitro antioxidant activity of AA-2betaG appeared to be comparable not only to that of AA-2G but also to that of AA.

Topics: Amidines; Animals; Antioxidants; Ascorbic Acid; Benzothiazoles; Erythrocytes; Hemolysis; Hydrogen-Ion Concentration; Molecular Structure; Sheep; Sulfonic Acids

Danshensu (3-(3,4-dihydroxyphenyl) lactic acid) and salvianolic acid B, two natural phenolic acids of caffeic acid derivatives isolated from Salvia miltiorrhiza root of the most widely used traditional Chinese medicine for the treatment of various cardiovascular diseases, have been reported to have potential protective effects from oxidative injury. To better understand their biological functions, the in vitro radical scavenging and antioxidant activities of danshensu and salvianolic acid B were evaluated along with vitamin C. Both danshensu and salvianolic acid B exhibited higher scavenging activities against free hydroxyl radicals (HO()), superoxide anion radicals (O(2)(-)), 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radicals and 2-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radicals than vitamin C. In contrary, danshensu and salvianolic acid B showed weaker iron chelating and hydrogen peroxide (H(2)O(2)) scavenging activities than vitamin C. As expressed as vitamin C equivalent capacity (VCEAC), the relative VCEAC values (mg/100ml) were in the order of salvianolic acid B (18.59) > danshensu (12.89) > vitamin C (10.00) by ABTS radical assay. The protective efficiencies against hydrogen peroxide induced human vein vascular endothelial cell damage were correlated with their antioxidant activities. Analysis of structure-activity relationship of these two compounds showed that the condensation and conjugation of danshensu and caffeic acid appears important for antioxidant activity. These results indicated that danshensu and salvianolic acid B are efficient radical scavengers and antioxidants, and salvianolic acid B is superior to danshensu. Their radical scavenging and antioxidant properties might have potential applications in food and healthcare industry.

Topics: Antioxidants; Ascorbic Acid; Benzofurans; Benzothiazoles; Biphenyl Compounds; Cell Survival; Chelating Agents; Endothelial Cells; Ferrous Compounds; Free Radical Scavengers; Humans; Hydrogen Peroxide; Hydroxyl Radical; Lactates; Oxidants; Picrates; Plant Roots; Salvia; Sulfonic Acids; Tetrazolium Salts; Thiazoles

A peroxidase (POX)-containing fraction was purified from buckwheat seed. The POX consisted of two isozymes, POX I and POX II, that were purified 6.6- and 67.4-fold, respectively. Their molecular weights were estimated to be 46.1 kDa (POX I) and 58.1 kDa (POX II) by gel filtration. While POX I and II each oxidized quercetin, o-dianisidine, ascorbic acid and guaiacol, only POX II oxidized ABTS. Kinetic studies revealed that POX I and II had lower K(m) values for quercetin (0.071 and 0.028 mM), ABTS (0.016 mM for POX II) and ascorbic acid (0.043 and 0.029 mM) than for o-dianisidine (0.229 and 0.137 mM) and guaiacol (0.288 and 0 ). The optimum pHs of POX I and II for various substrates were almost the same, except for quercetin; pH 8.0 for POX I and pH 4.5 for II. Their optimal temperatures were 30 degrees C (POX I) and 10 degrees C (POX II), and POX I was more stable than POX II above 30 degrees C.

Topics: Ascorbic Acid; Benzothiazoles; Dianisidine; Enzyme Stability; Fagopyrum; Guaiacol; Hydrogen-Ion Concentration; Isoenzymes; Kinetics; Peroxidase; Quercetin; Seeds; Sulfonic Acids; Temperature; Tissue Distribution

The aim of this study was to characterize the antioxidant activity of three ascorbic acid (AA) derivatives O-substituted at the C-2 position of AA: ascorbic acid 2-glucoside (AA-2G), ascorbic acid 2-phosphate (AA-2P), and ascorbic acid 2-sulfate (AA-2S). The radical-scavenging activities of these AA derivatives and some common low molecular-weight antioxidants such as uric acid or glutathione against 1,1-diphenyl-picrylhydrazyl (DPPH) radical, 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical cation (ABTS+), or galvinoxyl radical were kinetically and stoichiometrically evaluated under pH-controlled conditions. Those AA derivatives slowly and continuously reacted with DPPH radical and ABTS+, but not with galvinoxyl radical. They effectively reacted with DPPH radical under acidic conditions and with ABTS+ under neutral conditions. In contrast, AA immediately quenched all species of radicals tested at all pH values investigated. The reactivity of Trolox, a water-soluble vitamin E analogue, was comparable to that of AA in terms of kinetics and stoichiometrics. Uric acid and glutathione exhibited long-lasting radical-scavenging activity against these radicals under certain pH conditions. The radical-scavenging profiles of AA derivatives were closer to those of uric acid and glutathione rather than to that of AA. The number of radicals scavenged by one molecule of AA derivatives, uric acid, or glutathione was equal to or greater than that by AA or Trolox under the appropriate conditions. These data suggest the potential usage of AA derivatives as radical scavengers.

Topics: Ascorbic Acid; Benzhydryl Compounds; Benzothiazoles; Biphenyl Compounds; Chromans; Free Radical Scavengers; Glutathione; Hydrogen-Ion Concentration; Kinetics; Picrates; Sulfonic Acids; Uric Acid

There is considerable interest in the isolation of more potent antioxidant compounds to treat diseases involving oxidative stress. Thirty-three traditional Chinese medicine (TCM) extracts were examined for their antioxidant activity using the 2,2'-azinobis[3-ethylbenzothiazoline-6-sulfonate] (ABTS) assay. Five extracts with high activity (Cratoxylum cochinchinense, Cortex magnoliae officinalis, Psoralea corylifolia L, Curculigo orchioides Gaertn, and Glycyrrhiza uralensis Fisch.) were selected for further characterization. C. cochinchinense outperformed other extracts in most of the assays tested except phospholipid peroxidation inhibition, where P. corylifolia L showed higher activity. C. cochinchinense was particularly potent in inhibiting the formation of advanced glycation end products on proteins and strongly inhibited hypochlorous acid-induced DNA damage. We attempted to isolate the active ingredients from C. cochinchinense and obtained an extract (YCT) containing at least 90% mangiferin as identified by HPLC and mass spectrometry. However, YCT showed significantly higher activity in assays of phospholipid peroxidation, inhibition of protein glycation, and superoxide (O(2)(?-)) and peroxynitrite (ONOO(-)) scavenging, as compared with mangiferin, suggesting that the nonmangiferin constituents of YCT contribute to its additional antioxidant activities.

Topics: Antioxidants; Ascorbic Acid; Benzothiazoles; Chromatography, High Pressure Liquid; Clusiaceae; DNA Damage; Dose-Response Relationship, Drug; Hypochlorous Acid; Lipid Peroxidation; Lipids; Mass Spectrometry; Medicine, Chinese Traditional; Models, Chemical; Nitrogen; Peroxynitrous Acid; Phenol; Phospholipids; Sulfonic Acids; Superoxides; Tyrosine; Xanthine Oxidase; Xanthones

The free radical scavenging activity of South African red (n = 46) and white (n = 40) cultivar wines was determined using 2,2'-azinobis(3-ethylbenzothialozinesulfonic acid) radical cations (ABTS(.+)) and 2,2-diphenyl-1-picrylhydrazyl radicals (DPPH.). The total antioxidant activities (TAA) of red and white wines using ABTS(.+) were 14.916 and 0.939 mM Trolox, respectively, at corresponding total phenol (TP) contents of 2339.0 and 273.8 mg of gallic acid equiv/L. Ruby Cabernet wines had the lowest TAA(ABTS) (13.177 mM Trolox) of the red wines, whereas the TAA(ABTS) values of Chardonnay and Chenin blanc wines were the highest (1.060 mM Trolox) and lowest (0.800 mM Trolox) of the white wines. The TAA(DPPH) values were of the same magnitude as the TAA(ABTS) values, and similar trends were observed. TAA correlated (P < 0.001) with total phenol content of red (r = 0.935) and white (r = 0.907) wines, as well as flavanol content of red wines (r = 0.866) and tartaric acid ester content of white wines (r = 0.767). Canonical discriminant analysis using phenolic composition and antioxidant activity was applied to differentiate between red and white cultivar wines.

Topics: Anthocyanins; Antioxidants; Ascorbic Acid; Benzothiazoles; Biphenyl Compounds; Discriminant Analysis; Free Radical Scavengers; Fruit; Phenols; Picrates; South Africa; Sulfonic Acids; Vitis; Wine

The antioxidant capacity of butylated hydroxytoluene (BHT; 2,6-di-tert-butyl-p-cresol), propyl gallate (3,4,5-trihydroxybenzoic acid n-propyl ester), resveratrol (trans-3,4',5-trihydroxystilbene), and vitamins C (l-ascorbic acid) and E [(+)-alpha-tocopherol] was studied in chemical and biological systems. The chemical assays evaluated the capacity of these antioxidants to sequester 2,2'-azinobis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS.) and 1,1 diphenyl-2-picrylhydrazyl (DPPH.). A new colorimetric method to determine hydroxyl radical scavenging is also described. The biological tests use the eucaryotic cells of Saccharomyces cerevisiae treated with the antioxidants in the presence of the stressing agents apomorphine, hydrogen peroxide, and paraquat dichloride (methylviologen; 1,1'-dimethyl-4,4'-bipyridinium dichloride). The results in chemical systems showed that all of the antioxidants were able to significantly inhibit the oxidation of beta-carotene by hydroxyl free radicals. The assays in yeast showed that the antioxidant activity of the tested compounds depended on the stressing agent used and the mechanism of action of the antioxidant.

Topics: Antioxidants; Apomorphine; Ascorbic Acid; Benzothiazoles; beta Carotene; Biphenyl Compounds; Butylated Hydroxytoluene; Hydrogen Peroxide; Hydroxyl Radical; Oxidation-Reduction; Paraquat; Picrates; Propyl Gallate; Resveratrol; Saccharomyces cerevisiae; Stilbenes; Sulfonic Acids; Vitamin E

Melatonin and classic antioxidants possess the capacity to scavenge ABTSb+ with IC50s of 4, 11, 15.5, 15.5, 17 and 21 microm for melatonin, glutathione, vitamin C, trolox, NADH and NADPH, respectively. In terms of scavenging ABTSb+, melatonin exhibits a different profile than that of the classic antioxidants. Classic antioxidants scavenge one or less ABTSb+, while each melatonin molecule can scavenge more than one ABTSb+, probably with a maximum of four. Classic antioxidants do not synergize when combined in terms of scavenging ABTSb+. However, a synergistic action is observed when melatonin is combined with any of the classic antioxidants. Cyclic voltammetry indicates that melatonin donates an electron at the potential of 715 mV. The scavenging mechanism of melatonin on ABTSb+ may involve multiple-electron donations via intermediates through a stepwise process. Intermediates including the melatoninyl cation radical, the melatoninyl neutral radical and cyclic 3-hydroxymelatonin (cyclic 3-OHM) and N1-acetyl-N2-formyl-5-methoxykynuramine (AFMK) seem to participate in these reactions. More interestingly, the pH of the solution dramatically modifies the ABTSb+ scavenging capacity of melatonin while pH changes have no measurable influence on the scavenging activity of classic antioxidants. An acidic pH markedly reduces the ABTSb+ scavenging capacity of melatonin while an increased pH promotes the interaction of melatonin and ABTSb+. The major melatonin metabolites that develop when melatonin interacts with ABTSb+ are cyclic 3-OHM and AFMK. Cyclic 3-OHM is the intermediate between melatonin and AFMK, and cyclic 3-OHM also has the ability to scavenge ABTSb+. Melatonin and the metabolites which are generated via the interaction of melatonin with ABTSb+, i.e. the melatoninyl cation radical, melatoninyl neutral radical and cyclic 3-OHM, all scavenge ABTSb+. This unique cascade action of melatonin, in terms of scavenging, increases its efficiency to neutralized ABTSb+; this contrasts with the effects of the classic antioxidants.

Topics: Antioxidants; Ascorbic Acid; Benzothiazoles; Cations; Chromans; Chromatography, High Pressure Liquid; Electrochemistry; Free Radical Scavengers; Free Radicals; Glutathione; Hydrogen-Ion Concentration; Kynuramine; Mechanics; Melatonin; NAD; NADP; Sulfonic Acids

Tender Cocos nucifera L. (Palmacea) water (CW), variety Chandrasankara, was tested for its ability to scavenge free radicals, inhibit lipid peroxidation and protect hemoglobin from nitrite-induced oxidation. Fresh sample of CW scavenged 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2'-azino-bis(3-ethylbenz-thiazoline-6-sulfonic acid) (ABTS) and superoxide radicals but promoted the production of hydroxyl radicals and increased lipid peroxidation. The activity was most significant for fresh samples of CW and diminished significantly upon heat, acid or alkali treatment or dialysis. Maturity of coconut drastically decreased the scavenging ability of CW against DPPH, ABTS and superoxide radicals. CW protected hemoglobin from nitrite-induced oxidation to methemoglobin when added before the autocatalytic stage of the oxidation. Acid, alkali or heat treated or dialyzed CW showed a decreased ability in protecting hemoglobin from oxidation. The scavenging ability and protection of hemoglobin from oxidation may be partly attributed to the ascorbic acid, which is an important constituent of CW. As CW is a rich source of vitamins, amino acids and enzymes, etc., more than one active principle maybe involved.

Topics: Animals; Antioxidants; Ascorbic Acid; Benzothiazoles; Biphenyl Compounds; Cocos; Erythrocytes; Female; Free Radical Scavengers; Hemoglobins; Hot Temperature; Hydrazines; Hydrogen-Ion Concentration; Hydroxyl Radical; Kinetics; Lipid Peroxidation; Male; Methemoglobin; Oxidation-Reduction; Picrates; Plant Extracts; Rats; Sulfonic Acids; Superoxides

The antioxidant activity of hydroxytyrosol, hydroxytyrosol acetate, oleuropein, 3,4-dihydroxyphenylelenolic acid (3,4-DHPEA-EA) and 3,4-dihydroxyphenylelenolic acid dialdehyde (3,4-DHPEA-EDA) towards oxidation initiated by 2,2'-azobis(2-amidinopropane) hydrochloride in a soybean phospholipid liposome system was studied. The antioxidant activity of these olive oil phenols was similar and the duration of the lag phase was almost twice that of alpha-tocopherol. Trolox, a water-soluble analogue of alpha-tocopherol, showed the worst antioxidant activity. However, oxidation before the end of the lag phase was inhibited less effectively by the olive oil phenols than by alpha-tocopherol and Trolox. Synergistic effects (11-20% increase in lag phase) were observed in the antioxidant activity of combinations of alpha-tocopherol with olive oil phenols both with and without ascorbic acid. Fluorescence anisotropy of probes and fluorescence quenching studies showed that the olive oil phenols did not penetrate into the membrane, but their effectiveness as antioxidants showed they were associated with the surface of the phospholipid bilayer.

Topics: alpha-Tocopherol; Amidines; Antioxidants; Ascorbic Acid; Benzothiazoles; Chromans; Fluorescence Polarization; Glycine max; Kinetics; Liposomes; Membrane Fluidity; Olive Oil; Oxidation-Reduction; Phenols; Plant Oils; Sulfonic Acids

The antioxidant activities of the leaf and root extracts of Alchornea laxiflora, a plant used locally for the preservation of food items in Nigeria, were evaluated using the ferric thiocyanate method, horseradish peroxidase catalysed oxidation of 2,2 azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), beta-carotene linoleate model system and Fe(2+)/ascorbate/H(2)O(2)-induced rat liver microsomal lipid peroxidation. The crude hexane root (HR), methanol root (MR), methanol leaf (ML) and hexane leaf (HL) extracts from A. laxiflora were tested for antioxidant activities. Antioxidant activity decreased in the following order: HR (76.4%), MR (63%), ML (40%) and HL (38%) at a concentration of 0.05% v/v. The antioxidant activity of HR compared to that of butylated hydroxyanisole (BHA) (80%), a standard antioxidant. The total antioxidant activity (TAA) of the crude extracts suggests that activity is highest in the HR compared with the others. The TAA value was estimated to be 8.0 measured as mm of vitamin C equivalent. Six column chromatographic fractions (FI-FVI) from HR showed antioxidant activity to varying extents in the beta-carotene model system in the order of FII > FI > FVI > FIII > FIV > FV. FII exhibited the highest antioxidant activity in all model systems utilized, it recorded a higher antioxidant activity than BHA and quercetin in the beta-carotene linoleate and Fe(2+)/ascorbate/H(2)O(2). TLC analysis of fraction II revealed the presence of terpenoid compounds (radiant green coloration with 2,4 dinitrophenylhydrazine). Our results suggest that A. laxiflora contains potent natural antioxidants and may therefore be relevant in the preservation of lipid food products, which are prone to oxidation and rancidity.

Topics: Animals; Antioxidants; Ascorbic Acid; Benzothiazoles; beta Carotene; Euphorbiaceae; Food Preservatives; Iron; Lipid Peroxidation; Male; Microsomes; Phytotherapy; Plant Extracts; Plant Leaves; Plant Roots; Rats; Rats, Wistar; Sulfonic Acids; Thiocyanates

The 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical cation (ABTS (radical +)) decolorization assay was applied to evaluate the stoichiometric radical scavenging activity of ascorbic acid (AA) and two AA derivatives, 2-O-alpha-D-glucopyranosyl-L-ascorbic acid (AA-2G) and 2-O-alpha-D-glucopyranosyl-6-O-octanoyl-L-ascorbic acid (6-Octa-AA-2G). AA rapidly reacted with ABTS (radical +), and the reaction was completed within 10 min. In contrast, AA-2G and 6-Octa-AA-2G continuously reacted with ABTS (radical +), and the reaction was not completed after 2 h. The radical scavenging activity of AA-2G and 6-Octa-AA-2G in aqueous solutions at pH 4.0 and above was higher than that at pH 3.0, whereas AA showed no difference in the pH range 3 to 6. The amounts of ABTS (radical +) scavenged by one molecule of AA, AA-2G and 6-Octa-AA-2G after 2 h of reaction at pH 6.0 were approximately 2.0, 3.4 or 3.9 molecules, respectively. This study demonstrates that the quantity of ABTS (radical +) quenched by AA-2G and 6-Octa-AA-2G is superior to that of AA in a long-term reaction.

Topics: Ascorbic Acid; Benzothiazoles; Cations; Free Radical Scavengers; Free Radicals; Hydrogen-Ion Concentration; Sulfonic Acids

The contribution of each phytochemical to the total antioxidant capacity of apples was determined. Major phenolic phytochemicals of six apple cultivars were identified and quantified, and their contributions to total antioxidant activity of apples were determined using a 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging assay and expressed as vitamin C equivalent antioxidant capacity (VCEAC). Average concentrations of major phenolics and vitamin C in six apple cultivars were as follows (mg/100 g of fresh weight of apples): quercetin glycosides, 13.20; procyanidin B(2), 9.35; chlorogenic acid, 9.02; epicatechin, 8.65; phloretin glycosides, 5.59; vitamin C, 12.80. A highly linear relationship (r (2) > 0.97) was attained between concentrations and total antioxidant capacity of phenolics and vitamin C. Relative VCEAC values of these compounds were in the order quercetin (3.06) > epicatechin (2.67) > procyanidin B(2) (2.36) > phloretin (1.63) > vitamin C (1.00) > chlorogenic acid (0.97). Therefore, the estimated contribution of major phenolics and vitamin C to the total antioxidant capacity of 100 g of fresh apples is as follows: quercetin (40.39 VCEAC) > epicatechin (23.10) > procyanidin B(2) (22.07) > vitamin C (12.80) > phloretin (9.11) > chlorogenic acid (8.75). These results indicate that flavonoids such as quercetin, epicatechin, and procyanidin B(2) rather than vitamin C contribute significantly to the total antioxidant activity of apples.

Topics: Antioxidants; Ascorbic Acid; Benzothiazoles; Biflavonoids; Catechin; Flavonoids; Free Radicals; Fruit; Malus; Phenols; Proanthocyanidins; Quercetin; Sulfonic Acids

The ABTS/H(2)O(2)/HRP decoloration method is capable of determining both hydrophilic (in buffered media) and lipophilic (in organic media) antioxidant properties in complex samples. Now, we have adapted this method for on-line chromatographic determination. The easy, rapid and controlled generation of the ABTS radical and its great stability in buffered and organic media were important characteristics in the measurement of antioxidant activities. The HPLC-ABTS method used two pumps (one for isocratic eluting-phase and the other for preformed ABTS radical) and an UV-VIS diode array detector. The dual analysis of samples -- conventional (with UV-VIS detection) and ABTS-scavenging (at 600 nm) -- provided valuable on-line information about the correspondence between the presence of a determined compound and its possible antioxidant activity, and was applicable to both hydrophilic and lipophilic antioxidants (HAA and LAA). A comparison between HAA and LAA determined by the end-point method and by the on-line HPLC method is presented. The application to juices showed that both methods are suitable, sensitive and selective, gave similar values, and the HPLC-ABTS method contributed additional information about the antioxidant activity profile.

Topics: Antioxidants; Ascorbic Acid; Benzothiazoles; Chromatography, High Pressure Liquid; Free Radicals; Horseradish Peroxidase; Hydrogen Peroxide; Indicators and Reagents; Online Systems; Spectrophotometry; Structure-Activity Relationship; Sulfonic Acids

To express the antioxidant capacity of plant foods in a more familiar and easily understood manner (equivalent to vitamin C mg/100 g), two stable radical species, ABTS(*)(-) and DPPH(*), commonly used for antioxidant activity measurements, were employed independently to evaluate their efficacies using apple polyphenolic extracts and seven polyphenolic standards including synthetic Trolox. Their antioxidant activities were expressed as vitamin C equivalent antioxidant capacity (VCEAC) in mg/100 g apple or mg/100 mL of the reference chemical compounds in 10 and 30 min using the ABTS(*)(-) and DPPH(*) scavenging assays, respectively. The antioxidant capacity of Gala apples and seven phenolic standards, determined by both ABTS(*)(-) and DPPH(*) scavenging assays, showed a dose-response of the first-order. Fresh Gala apples had a VCEAC of 205.4 +/- 5.6 mg/100 g using the ABTS assay, and the relative VCEACs of phenolic standards were as follows: gallic acid > quercetin > epicatechin > catechin > vitamin C > rutin > chlorogenic acid > Trolox. With the DPPH radical assay, the VCEAC of fresh Gala apples was 136.0 +/- 6.6 mg/100 g, and the relative VCEACs of seven phenolic standards were, in decreasing order, as follows: gallic acid > quercetin > epicatechin > catechin > or = vitamin C > Trolox > rutin > chlorogenic acid. Because the ABTS assay can be used in both organic and aqueous solvent systems, employs a specific absorbance at a wavelength remote from the visible region, and requires a short reaction time, it is a more desirable method than the DPPH assay. Therefore, it is recommended that antioxidant capacity be expressed as vitamin C mg/100 g equivalent (VCEAC) using the ABTS assay.

Topics: Antioxidants; Ascorbic Acid; Benzothiazoles; Biphenyl Compounds; Catechin; Chlorogenic Acid; Chromans; Free Radical Scavengers; Free Radicals; Gallic Acid; Kinetics; Malus; Oxidation-Reduction; Phenols; Picrates; Plant Extracts; Plants, Edible; Quercetin; Rutin; Sulfonic Acids

Peroxynitrite is implicated in numerous human diseases. Hence, there is considerable interest in potential therapeutic peroxynitrite scavengers. It has been claimed that uric acid is a powerful peroxynitrite scavenger. We previously observed that uric acid is a powerful inhibitor of tyrosine nitration induced by peroxynitrite, but fails to prevent alpha(1)-antiproteinase (alpha(1)-AP) inactivation induced by peroxynitrite. However, the reactivity of peroxynitrite is significantly modified by bicarbonate and this has not been considered in evaluating the scavenging activity of uric acid and other endogenous antioxidant compounds. In the presence of bicarbonate (25 mM), the ability of uric acid, ascorbate, Trolox, and GSH to inhibit peroxynitrite-mediated tyrosine and guanine nitration is decreased. Protection against peroxynitrite-mediated alpha(1)-AP inactivation is also decreased by ascorbate, Trolox, and GSH, but it is enhanced by uric acid. Bicarbonate also inhibits the ability of these compounds to prevent peroxynitrite-mediated ABTS radical cation formation. However, the abilities of these antioxidants to prevent peroxynitrite-mediated bleaching of pyrogallol red are enhanced by bicarbonate. These results show that physiologic concentrations of bicarbonate substantially modify the ability of uric acid to prevent peroxynitrite-mediated reactions. This study highlights the need to use several different assays in the presence of physiologically relevant concentrations of bicarbonate when assessing compounds for peroxynitrite scavenging, in order to avoid misleading results.

Topics: alpha 1-Antitrypsin; Antioxidants; Ascorbic Acid; Benzothiazoles; Bicarbonates; Chromans; Coloring Agents; Glutathione; Guanine; Humans; Indicators and Reagents; Peroxynitrous Acid; Pyrogallol; Reactive Nitrogen Species; Serine Proteinase Inhibitors; Sulfonic Acids; Tyrosine; Uric Acid

Four spectrophotometric methods of determination of antioxidant capacity: a method based on the scavenging of the l,1-diphenyl-2-picrylhydrazyl (DPPH) free radical, the "ferric-reducing ability of plasma" (FRAP), a method based on reduction of the 2.2'-azinobis (3-ethylbenzthiazolinesulfonate) free radical (ABTS.+) and a kinetic method based on the oxidation of dihydro-2,7-dichlorofluorescein by 2,2'-azobis(2-amidopropane) (ABAP) were compared with respect to standard antioxidants (ascorbate, glutathione, Trolox and urate) and human blood plasma. Various reactivities of standard antioxidants in different tests were found. glutathione showing a low reactivity in the FRAP assay. Kinetic measurements show that the reduction of indicators, especially by blood plasma, may not be complete at recommended times of the assays and the time of measurement is an important parameter when comparing the results.

Topics: Adult; Amidines; Antioxidants; Ascorbic Acid; Benzothiazoles; Biphenyl Compounds; Chemistry, Clinical; Female; Glutathione; Humans; Kinetics; Male; Middle Aged; Oxidative Stress; Picrates; Plasma; Spectrophotometry; Sulfonic Acids; Uric Acid

A novel post-addition method, based on the trapping of ABTS-radicals, is applied for studying the total antioxidant capacity of seminal plasma. A remarkable profile is observed, in which seminal plasma quenches radicals in a continuous, relatively slow fashion. Five putative antioxidants present in seminal plasma were studied using the same assay. Some of the compounds such as ascorbic acid, alpha-tocopherol and uric acid exert immediate, fast radical trapping, whereas hypotaurine and tyrosine give rise to the same slow radical trapping curve as seminal plasma. Due to this slow, continuous radical trapping, quantification of the total antioxidant capacity (expressed as trolox equivalent antioxidant capacity, TEAC) strongly depends on the chosen time point after onset of radical trapping. When determined during the slow antioxidant trapping phase, tyrosine has a powerful antioxidant capacity, which in combination with its relatively high plasma concentration makes it an important contributor to the total antioxidant capacity of seminal plasma.

Topics: Amidines; Antioxidants; Ascorbic Acid; Benzothiazoles; Drug Synergism; Free Radicals; Humans; Indicators and Reagents; Male; Oxidants; Oxidation-Reduction; Semen; Spectrophotometry; Sulfonic Acids; Taurine; Tyrosine; Uric Acid; Vitamin E

Transient kinetic analysis of biphasic, single turnover data for the reaction of 2,2'-azino-bis[3-ethylbenzthiazoline-6-sulfonic acid] (ABTS) with horseradish peroxidase (HRPC) compound II demonstrated preequilibrium binding of ABTS (k(+5) = 7.82 x 10(4) M(-)(1) s(-)(1)) prior to rate-limiting electron transfer (k(+6) = 42.1 s(-)(1)). These data were obtained using a stopped-flow method, which included ascorbate in the reaction medium to maintain a low steady-state concentration of ABTS (pseudo-first-order conditions) and to minimize absorbance changes in the Soret region due to the accumulation of ABTS cation radicals. A steady-state kinetic analysis of the reaction confirmed that the reduction of HRPC compound II by this substrate is rate-limiting in the complete peroxidase cycle. The reaction of HRPC with o-diphenols has been investigated using a chronometric method that also included ascorbate in the assay medium to minimize the effects of nonenzymic reactions involving phenol-derived radical products. This enabled the initial rates of o-diphenol oxidation at different hydrogen peroxide and o-diphenol concentrations to be determined from the lag period induced by the presence of ascorbate. The kinetic analysis resolved the reaction of HRPC compound II with o-diphenols into two steps, initial formation of an enzyme-substrate complex followed by electron transfer from the substrate to the heme. With o-diphenols that are rapidly oxidized, the heterolytic cleavage of the O-O bond of the heme-bound hydrogen peroxide (k(+2) = 2.17 x 10(3) s(-)(1)) is rate-limiting. The size and hydrophobicity of the o-diphenol substrates are correlated with their rate of binding to HRPC, while the electron density at the C-4 hydroxyl group predominantly influences the rate of electron transfer to the heme.

Topics: Ascorbic Acid; Benzothiazoles; Binding Sites; Horseradish Peroxidase; Hydrogen Peroxide; Indicators and Reagents; Kinetics; Models, Chemical; Nuclear Magnetic Resonance, Biomolecular; Oxidation-Reduction; Phenols; Reducing Agents; Substrate Specificity; Sulfonic Acids

A simple spectrophotometric method of determination of peroxyl radical-trapping capacity (PRTC) of body fluids and food products is proposed. In this method, decomposition of 2,2'-azobis(2-amidopropane) hydrochloride (ABAP) is the source of peroxyl and alkoxyl radicals which oxidize 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) to a green cation radical. Antioxidant present in a sample inhibit the reaction; the induction time of the reaction is proposed as a parameter enabling determination of antioxidant content. Standard assay conditions are: 20 mM ABAP and 150 microM ABTS in 0.1 M phosphate buffer, pH 7.0, at 37 degrees C; absorbance is monitored at 414 nm. A 10-min assay allows for determination of the induction time of appropriately diluted sample. As examples of application of this method, PRTC values of several types of beverages are reported.

Topics: Alcoholic Beverages; Amidines; Amino Acids; Antioxidants; Ascorbic Acid; Benzothiazoles; Chromans; Epinephrine; Free Radicals; Indicators and Reagents; Oxidation-Reduction; Peroxides; Plasma; Spectrophotometry; Sulfonic Acids; Time Factors

This study introduces a simple direct antioxidant assay, based on the reduction of the ABTS.+ radical cation, and compares it with the myoglobin/ABTS.+ assay. The methods give closely similar results, establishing that the antioxidants studied to date in the latter assay act by scavenging the ABTS.+ radical cation and not by inhibiting its formation through reduction of ferryl myoglobin or reaction with H2O2.

Topics: Antioxidants; Ascorbic Acid; Benzothiazoles; Colorimetry; Free Radical Scavengers; Free Radicals; Hydrogen Peroxide; Myoglobin; Oxidation-Reduction; Sulfonic Acids; Uric Acid; Vitamin E

The accumulation of 2.2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical catalyzed by peroxidase can be inhibited by the presence of L-ascorbic acid in the reaction medium, this inhibition delaying the accumulation of the ABTS radical and giving rise to a lag time. A kinetic approach to explain this lag time is presented, which also makes it possible to determine the amount of L-ascorbic acid in the reaction medium. The stoichiometry of the system was determined as 1 mol of L-ascorbic reducing 2 mol of ABTS radicals. L-Ascorbic acid is not the only compound to have this ability, since other antioxidant compounds also react with the ABTS radical. We studied the ABTS/H2O2/horseradish peroxidase system in the presence of L-ascorbic acid and other antioxidant compounds. The influence of such factors as pH, enzyme concentration, and L-ascorbic acid concentration was studied. A good correlation between the lag time and the L-ascorbic acid present in the medium was observed, and under optimal conditions, the method could determine as little as 0.65 nmol of L-ascorbic acid. Based on our findings, we propose a method to measure the total antioxidant activity of different compounds related to L-ascorbic acid and apply this method to determining the total antioxidant activity present in fruit juices.

Topics: Antioxidants; Ascorbic Acid; Benzothiazoles; Calibration; Catalysis; Enzyme Inhibitors; Food Analysis; Free Radicals; Horseradish Peroxidase; Hydrogen-Ion Concentration; Kinetics; Metmyoglobin; Oxidation-Reduction; Spectrophotometry; Sulfonic Acids

The 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical cation can be generated by incubation of ABTS and 2,2'-azo-bis(2- amidinopropane) at 45 degrees C. The ABTS radical cation is stable for several minutes at room temperature and reacts quantitatively and instantaneously with several antioxidants, such as Trolox, ascorbic acid, uric acid, cysteine, glutathione and bilirubin. In contrast, the ABTS radical cation reacts slowly with albumin. When serum is added to a solution of the ABTS radical cation, the bleaching of the radical follows biphasic kinetics, with a fast decay followed by a slow decay that takes place within several minutes. The fast decay is primarily due to uric acid, while the slow decay is related to the protein content of the sample. We propose that this procedure can provide an independent and simultaneous evaluation of the low molecular weight and protein antioxidants present in biological samples such as serum.

Topics: Antioxidants; Ascorbic Acid; Benzothiazoles; Bilirubin; Chromans; Cysteine; Glutathione; Indicators and Reagents; Sulfonic Acids; Temperature; Time Factors; Uric Acid

Fruits and vegetables contain several classes of compounds that can potentially contribute to antioxidant activity, including vitamins, simple and complex phenolics, sulphur-containing compounds and glucosinolates. The glucosinolates are found in high concentration in many cruciferous vegetables, and it is well established that their breakdown products induce endogenous antioxidant defences such as quinone reductase and glutathione S-transferase in cells and in vivo. Despite the anticarcinogenic effect of these compounds in animal models, the direct antioxidant properties of this class of compounds have not been systematically studied. We therefore examined the free radical-scavenging properties of representative extracts and of purified glucosinolates from cruciferous vegetables, by measuring their effect on ascorbate- or NADPH/iron-induced peroxidation of human liver microsomes, ascorbate/iron-induced peroxidation on phospholipid liposomes, iron chelation and hydroxyl radical scavenging using the deoxyribose assay, total antioxidant potential using ABTS (2,2'-azinobis(3-ethyl-benzothiazoline-6-sulphonate)) and the bleomycin assay. Most of the extracts from cruciferous vegetables exhibited some antioxidant properties, although extracts from cooked Brussels sprouts increased the rate of microsomal lipid peroxidation. The effects in these assays were dependent upon processing and species of crucifer, and the glucosinolate content appeared to play a minor role in these effects, since purified glucosinolates exhibited only weak antioxidant properties. The total antioxidant activities of extracts from cooked and autolysed Brussels sprouts were identical within experimental error. This is probably due to the content of phenolics which is unaltered by autolysis, despite the differences between these samples in other assays especially NADPH-iron-induced lipid peroxidation of human liver microsomes. The results demonstrate that glucosinolates are unlikely to account for the direct antioxidant effects of extracts from cruciferous vegetables.

Topics: Antioxidants; Ascorbic Acid; Benzothiazoles; Bleomycin; Brassica; Deoxyribose; DNA Damage; Free Radical Scavengers; Glucosinolates; Humans; Hydroxyl Radical; Iron; Lipid Peroxidation; Liposomes; Microsomes, Liver; NADP; Oxidation-Reduction; Phospholipids; Plant Extracts; Species Specificity; Sulfonic Acids; Vegetables

The reactions between Trolox C, a water-soluble vitamin E analogue, and several oxidizing free radicals including the hydroxyl radical and various peroxy radicals were examined by using the pulse-radiolysis technique. The results demonstrate that Trolox C may undergo rapid one-electron-transfer reactions as well as hydrogen-transfer processes; the resulting phenoxyl radical is shown to be relatively stable, in common with the phenoxyl radical derived from vitamin E. The reactions between the Trolox C phenoxyl radical and a variety of biologically relevant reducing compounds were examined by using both pulse radiolysis and e.s.r. The results demonstrate that the Trolox C phenoxyl radical is readily repaired by ascorbate (k = 8.3 x 10(6) dm3.mol-1.s-1) and certain thiols (k less than 10(5) dm3.mol-1.s-1) but not by urate, NADH or propyl gallate. Evidence from e.s.r. studies indicates that thiol-containing compounds may also enter into similar repair reactions with the alpha-tocopherol phenoxyl radical. Kinetic evidence is presented that suggests that Trolox C may 'repair' proteins that have been oxidized by free radicals.

Topics: Ascorbic Acid; Benzopyrans; Benzothiazoles; Binding, Competitive; Chromans; Electron Spin Resonance Spectroscopy; Electron Transport; Free Radicals; Hydrogen-Ion Concentration; Indicators and Reagents; Oxidation-Reduction; Pulse Radiolysis; Sulfhydryl Compounds; Sulfonic Acids

A spectrophotometric method for the determination of serum uric acid based on the oxidation of 2,2'-azino-di(3-ethylbenzthiazoline-6-sulphonate) by use of uricase and peroxidase has already been reported. The method is very precise (CV less than 4.7%). The standard curve is linear up to 4640 mumol/L. Comparison with other enzymatic methods gave good correlation. The method gave results 9% lower than the phosphotungstate method. The effects of bilirubin, haemoglobin, glucose, ascorbic acid, anticoagulants and purine compounds were studied. The reference values for this method are 140.8-407.8 mumol/L for female subjects and 145.6-514.7 mumol/L for male subjects.

Topics: Anticoagulants; Ascorbic Acid; Benzothiazoles; Bilirubin; Blood Glucose; Hemolysis; Humans; Indicators and Reagents; Purines; Reference Values; Sulfonic Acids; Uric Acid