Abstract: It is important to search for the ingredients with SOD-like activity present in Chinese traditional drugs. Four classes of constituents including fifteen compounds isolated from Chinese rhubarb were studied for their SOD-like activity by determining the percentage of scavenging effect of the superoxide radical anion (O2^-·), (S%), The results showed that the SOD-like activities of four tanninoid compounds were stronger among which (-)-epi- catechin has the strongest SOD-like activity at lower concentrations: the activity of five stilbene compounds is weaker:while chrysophanol-8-glucoside and desoxyrhaponticin have no SOD-like activity and, on the contrary.may promote the production of O2^-·.

Key words: Rhubarb, Superoxide radical anion, SOD-like activity