Resveratrols as target compounds in the evaluation of antioxidant activity of Southern Brazilian red wines

Abstract

Resveratrols (cis-resveratrol, trans-resveratrol, cis-piceid, trans-piceid) were quantified by HPLC-DAD in Vitis vinifera red wines, cv. Cabernet Franc, Merlot, Sangiovese and Syrah, 2006 and 2007 vintages, from the São Joaquim region, a new grape growing region at southern Brazil. The effect of chronic consumption of these wines on the antioxidant activity was monitored in C57BL6 LDL receptor knockout mice through biomonitoring of the total antioxidant capacity of plasma (FRAP),  the endogenous lipid peroxidation (TBARS), the oxidative damage to proteins by carbonylation (CP) and  the reduced glutathione (GSH). The results showed red wines from this region had surprisingly high levels of resveratrols (the predominant forms were glycoside and trans), demonstrating the potential of this region to produce wines rich in resveratrols. The total resveratrol concentrations (sum of cis and trans-piceid and cis and trans-resveratrol forms) ranged from 12.7 to 52.8 mg L^-1 (27.4 mg L^-1 in average). Biomonitoring of antioxidant activity in vivo revealed that consumption of these wines increased the antioxidant capacity. It was observed a significant increase (p< 0.05) in FRAP levels (~ 60% average), as well as a significant reduction of TBARS (ranged from 30% to 47%) and of CP levels (ranged from 33 to 42%). Moreover, significant correlations were found between the increase of antioxidant capacity promoted by wine consumption and the contents of resveratrols, supporting the important biological activity of these compounds.