Antioxidant activities of five Chinese rice wines and the involvement of phenolic compounds

Chinese rice wine has been claimed to have health-promoting effects, which may be related to the antioxidant activity in vivo. In this study, total antioxidant, reducing, free radical scavenging, and superoxide anion radical scavenging activities were determined in five Chinese rice wines (Guyuelongshan, Hongqu, Shousheng, Foshou, and Nuomi) comparing with synthetic antioxidants, such as butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT). Ten individual phenolic compounds including caffeic acid, syringic acid, and rutin, (−)-epicatechin, (+)-catechin, gallic acid, vanillic acid, p-coumaric acid, ferulic acid and quercetin, were identified and quantified by HPLC. Results indicated that rice wines exhibited high antioxidant power, and that total antioxidant activity, reducing capacity and free radical scavenging activity were highly correlated with total phenolic content. Nuomi with the highest content of phenolic compounds showed the highest antioxidant activity, while Foshou had the lowest content with lowest activity. Syringic acid and (+)-catechin contributed most to the phenolic compounds and were highly correlated with all antioxidant properties (r2 > 0.75). However, vanillic acid, p-coumaric acid and quercetin showed little contribution to the antioxidant function.