Search results for "ABTS"
showing 10 items of 55 documents
Interference of carbidopa and other catechols with reactions catalyzed by peroxidases
2018
Abstract Background A number of compounds, including ascorbic acid, catecholamines, flavonoids, p-diphenols and hydrazine derivatives have been reported to interfere with peroxidase-based medical diagnostic tests (Trinder reaction) but the mechanisms of these effects have not been fully elucidated. Methods Reactions of bovine myeloperoxidase with o-dianisidine, bovine lactoperoxidase with ABTS and horseradish peroxidase with 4-aminoantipyrine/phenol in the presence of carbidopa, an anti-Parkinsonian drug, and other catechols, including l -dopa, were monitored spectrophotometrically and by measuring hydrogen peroxide consumption. Results Chromophore formation in all three enzyme/substrate sy…
LC‐ESI / HRMS analysis of glucosinolates, oxylipins and phenols in Italian rocket salad ( Diplotaxis erucoides subsp. erucoides (L.) DC .) and evalua…
2021
BACKGROUND This study investigated the chemical profile and biological activity of Diplotaxis erucoides subsp. erucoides (L.) DC. (Brassicaceae) collected in Sicily (Italy). RESULTS Liquid chromatography coupled with electrospray ionization and high-resolution mass spectrometry (LC-ESI/HRMS) analysis of the ethanol extract revealed the presence of 42 compounds - glucosinolates, hydroxycinnamic acids, flavonoids, and oxylipins. The extract was tested for its antioxidant activity using 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic) acid (ABTS), ferric reducing ability power (FRAP), and β-carotene bleaching tests. Promising protection from lipid peroxida…
Antioxidant activity and phenolic composition in pomegranate (Punica granatumL.) genotypes from south Italy by UHPLC-Orbitrap-MS approach
2018
Background: Pomegranate fruits are a rich source of polyphenols with numerous health-promoting effects. Pomegranate juices of five genotypes ('Mollar', 'Kingdom', 'Dente di Cavallo', and two old populations 'Francofonte' and 'Santa Tecla') were evaluated regarding anthocyanin and non-anthocyanin phenolic contents using ultrahigh performance liquid chromatography (UHPLC)-Orbitrap-mass spectrometry (MS). Moreover, total antioxidant activity (TAA) was evaluated using a 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) assay.; Results: Twenty-three phenolic compounds were identified. Cyanidin-3,5-O-diglucoside and pelargonidin-3,5-O-diglucoside were the most represent…
Supercritical CO2 extraction of oil, fatty acids and flavonolignans from milk thistle seeds: Evaluation of their antioxidant and cytotoxic activities…
2015
International audience; The optimal conditions of supercritical carbon dioxide (SC-CO2) (160-220 bars, 40-80 degrees C) technology combined with co-solvent (ethanol), to recover oil, flavonolignans (silychristin, silydianin and silybinin) and fatty acids from milk thistle seeds, to be used as food additives and/or nutraceuticals, were studied. Moreover, the antioxidant and cytotoxic activities of the SC-CO2 oil seeds extracts were evaluated in Caco-2 carcinoma cells. Pressure and temperature had a significant effect on oil and flavonolignans recovery, although there was not observed a clear trend. SC-CO2 with co-solvent extraction at 220 bars, 40 degrees C was the optimum treatment to recov…
Elucidation of antioxidant properties of wood bark derived saturated diarylheptanoids: a comprehensive (DFT-supported) understanding.
2013
A series of diarylheptanoids, namely 1,7-bis-(3,4-dihydroxyphenyl)-heptan-3-one-5-O-D-xylopyranoside (oregonin), 1,7-bis-(3,4-dihydroxyphenyl)-3-hydroxyheptane-5-O-β-D-xylopyranoside and 1,7-bis-(4-hydroxyphenyl)-heptane-3-one-5-O-β-D-glucopyranoside (platyphylloside), were isolated from the bark of alder family trees, a species widely spread over in Europe. As antioxidants, these natural polyphenols have a promising potential in various fields of application, but their redox reactivity is insufficiently characterized. In this work, their antioxidant activity is described using assays based on DPPH and ABTS(+) radical scavenging, oxygen anion radicals (O2(-)) quenching. The standardized ORA…
Improved bioaccessibility and antioxidant capacity of olive leaf ( Olea europaea L.) polyphenols through biosorption on Saccharomyces cerevisiae
2016
Abstract Olive ( Olea europaea L.) leaves (OL) are natural by-products that can be used as an advantageous rich source of bioactive compounds, especially polyphenols. This study investigated the potential use of Saccharomyces cerevisiae as a new carrier of OL antioxidants and a means to protect their bioactivity during simulated gastrointestinal digestion. The biosorption on S. cerevisiae allowed the recovery of 25.17 mg/g and 49.40% of the polyphenols from olive leaf (var. Chemlali ) infusions. Both infusions and suspensions before and after biosorption were analyzed for total soluble polyphenols and total antioxidant capacity (oxygen radical absorbance capacity (ORAC) and trolox equivalen…
V2O5 nanowires with an intrinsic peroxidase-like activity
2010
V2O5 nanowires exhibit an intrinsic catalytic activity towards classical peroxidase substrates such as 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 3,3,5,5,-tetramethylbenzdine (TMB) in the presence of H2O2. These V2O5 nanowires show an optimum reactivity at a pH of 4.0 and the catalytic activity is dependent on the concentration. The Michaelis-Menten kinetics of the ABTS oxidation over these nanowires reveals a behavior similar to that of their natural vanadium-dependent haloperoxidase (V-HPO) counterparts. The V2O5 nanowires mediate the oxidation of ABTS in the presence of H2O2 with a turnover frequency (k(cat)) of 2.5 x 10(3) s(-1). The K-M values of the V2O5 nanowire…
Behavior of the total antioxidant status in a group of subjects with metabolic syndrome.
2014
AIM: Our purpose was to examine the total antioxidant status (TAS) in subjects with metabolic syndrome (MS) subdivided according to the presence or not of diabetes mellitus. METHODS: We enrolled 106 subjects (45 women, 61 men) with MS subsequently subdivided in diabetics (14 women, 29 men) and nondiabetics (31 women, 29 men). TAS was obtained using an Assay kit which relies on the ability of plasma antioxidant substances to inhibit the oxidation of 2,2'-azino-bis(3-ethylbenzthiazoline sulfonic acid) to the radical ABTS+. RESULTS: In the group of MS subjects a significant decrease in TAS (p<0.05) in comparison with normal controls was evident. This difference was present between normal subje…
Different effectiveness of two pastas supplemented with either lipophilic or hydrophilic/phenolic antioxidants in affecting serum as evaluated by the…
2017
Effectiveness in improving serum antioxidant status of two functional pastas was evaluated by the novel Antioxidant/ Oxidant Balance (AOB) parameter, calculated as Antioxidant Capacity (AC)/Peroxide Level ratio, assessed here for the first time. In particular, Bran Oleoresin (BO) and Bran Water (BW) pastas, enriched respectively with either lipophilic (tocochromanols, carotenoids) or hydrophilic/phenolic antioxidants extracted from durum wheat bran, were studied. Notably, BO pasta was able to improve significantly (+65%) serum AOB during four hours after intake similarly to Lisosan G, a wheat antioxidant-rich dietary supplement. Contrarily, BW pasta had oxidative effect on serum so as conve…
Evaluation of the antioxidant capacity, furan compounds and cytoprotective/cytotoxic effects upon Caco-2 cells of commercial Colombian coffee.
2017
Abstract Antioxidant capacity (AC), total phenolics (TPs), furan compounds (HMF and furfural F) and cytoprotective/cytotoxic effects upon Caco-2 cells (MTT, cell cycle and reactive oxygen species (ROS)) were evaluated in Colombian coffee (2 ground and 4 soluble samples). The AC (ABTS and FRAP), TPs and HMF ranged between 124–722, 95–802 μmoles Trolox/g, 21–100 mg gallic acid/g and 69–2900 mg/kg, respectively. Pretreatment of cells for 24 h with lyophilized coffee infusions at the highest dose without cytotoxic effects (500 μg/mL) significantly prevented the decrease in cell viability compared to control stress with H2O2 (5 mM/2 h), recovering viability to values between 34% and 45% and rest…