In vivo antioxidant activity of methanol extract from quinoa fermented with Rhizopus oligosporus

Abstract

Previously, this author reported that the fermentation of quinoa with Rhizopus oligosporeus increased antioxidant activity, and the antioxidant activity of the 80% methanol extract of the fermented quinoa (Q-tempeh) was higher than the other extracts with n-hexane and water in vitro. In this paper, to clarify a beneficial effect of the fermentation of quinoa with R. oligosporus, the antioxidant activity of 80% methanol extract of Q-tempeh was investigated in rats ex vivo and in vivo. In the ex vivo experiment, the 80% methanol extract from Q-tempeh increased both activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in the liver, and accelerated the production of 12-hydroxy-eicosatetraenoic acid (12-HETE) in the lung. In rats fed vitamin E-free diets with 80% methanol extract of Q-tempeh, the α-tocopherol concentration, thiobarbituric acid-reactive substance (TBARS) value, and activities of GSH-Px and SOD in serum showed a similar concentration to those of the control rats fed a vitamin E-supplemented diet. However, the hepatic GSH-Px and SOD activities were higher than those in the control rats. On the other hand, in rats fed a vitamin E-free diet with the 80% methanol extract of quinoa, the serum a-tocopherol level was lower, and both TBARS values of serum and liver were higher than those in the control rats. From these results, the 80% methanol extract of Q-tempeh was inferred to be an active superoxide scavenger and peroxide reducer in vivo.