The antioxidant activities of three popular ingredients of traditional Chinese medicine, namely Angelica sinensis (AS), Lycium barbarum (LB) and Poria cocos (PC) were evaluated in this study. The results showed that aqueous extracts of these crude drugs exhibited antioxidant activities in a concentration-dependent manner. All extracts displayed an inhibitory effect on FeCl2-ascorbic acid induced lipid peroxidation in rat liver homogenate in vitro, with the order of activity LB > AS > PC. The tested extracts showed a superoxide anion scavenging activity ranging from 28.8% to 82.2% and anti-superoxide activity varying from 38.0% to 84.5%. Among the different extracts, LB extract exhibited the lowest IC50 values (0.77-2.55 microg/mL) in all model systems tested in this study. The present study concludes that LB extract possessed the strongest inhibition on malondialdehyde formation in rat liver homogenate, and superoxide anion scavenging and anti-superoxide formation activities. These results also suggest that LB extract is a good source of antioxidant agent in the daily dietary supplement.

2004 John Wiley & Sons, Ltd.