Abstract
Nowadays, there is considerable interest in finding out about antioxidants thatare consumed in the habitual diet. It is known that polyphenols are involved in reducing therisk of diseases associated with oxidative stress. The in vitro antioxidant activity of theprincipal wine polyphenolic compounds (catechins, procyanidins, anthocyanins andpyranoanthocyanins) was studied in this work. Four distinct methods were used to assessthe antioxidant capacity of the tested compounds: inhibition of peroxynitrite mediatedtyrosine nitration, TEAC (Trolox equivalent antioxidant capacity assay), FRAP (Ferricreducing/antioxidant power assay) and TBARS (thiobarbituric acid reactive substances)methods. In general, it could be concluded that procyanidins were, among the in vitrotested groups, the ones which showed more antioxidant capacity using the four differentmethods, followed by anthocyanins and pyranoanthocyanins. On the basis of the simpleregression testing, there was a statistically significant relationship between these differentmethods used in aqueous phase (r > 0.92). However, no correlation was found between theresults obtained in lipid media with the TBARS method and those obtained in the aqueousmedia (peroxynitrite scavenging activity, TEAC and FRAP methods).
Highlights
Reactive nitrogen and oxygen species (RNS, ROS) have been intensively studied in recent years with regard to their relevant physiological and pathological importance connected with oxidative stress
Four in vitro methods based on different mechanisms of determination of the antioxidant capacity were used to test polyphenolic compounds
The the Trolox equivalent antioxidant capacity (TEAC) assay, was used for measuring the capacity of tested compounds to scavenge the stable cation radical ABTS+ compared to Trolox C, a water soluble analogue of vitamin E
Summary
Reactive nitrogen and oxygen species (RNS, ROS) have been intensively studied in recent years with regard to their relevant physiological and pathological importance connected with oxidative stress. The main dietary sources of anthocyanin (Figure 1), pigments responsible for the redblue color, include red-colored fruits, vegetables and red wine. They have shown ability to prevent lipid oxidation and scavenging activity against free radicals [9]. There are different methods to evaluate the in vitro antioxidant capacity of isolated compounds, mixtures of compounds, biological fluids and tissues which involve different mechanisms of determination of antioxidant activity, for example: chemical methods based on scavenging of ROS or RNS such as peroxynitrite [12], the hydroxyl radical and superoxide [13]. The purpose of the present study was 2-fold: 1) to evaluate the in vitro antioxidant activity of catechins, procyanidins, anthocyanins and pyranoanthocyanins from wine by four methods based on different mechanisms 2) to investigate statistically the inter-relationship between the in vitro methods used
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