Use of red blood cell membranes to evaluate the antioxidant potential of plant extracts.

Antioxidant phytochemicals in fruits and vegetables of a vegetarian diet may account for the reduced risk of aging and stress oxidative associated diseases. In this study, a simple, rapid and accurate new bioassay for the determination of the antioxidant activity of purified or crude plant extracts and thier interactions is described, based on the fluorimetric determination of thiobarbituric acid reactive substances (TBARS) released by UV-B radiated red blood cell (RBC) ghosts. Pure resveratrol, white and red wine and pomegranate juice (PJ) were used as antioxidant source to test the biological method. TBARS production is a function of radiation time, the number of RBC ghosts in the radiated sample and the loaded antioxidant. The antioxidant activity of resveratrol was detected at a submicromolar concentration range [0.02 μg/mL-0.1 μmol/L]. The activity of red wine was almost 10 times higher than that of white wine, and PJ juice had the highest activity. Submaximal protective effects of PJ and red wine were additive.