Abstract: In order to investigate the anti-oxidation effect, the health protection function of Rhodiola Sacra and its mechanism of the function, HPLC was used to determine the Rodiola-glucoside content in Rhodiola extract. For observation of superoxide anion radicals（O2-·） scavenging effect, the pyrogallol auto-oxidation method and method of xanthine-xanthine oxidase chemiluminescence of luminol （X-XO-L） were used. For evaluation of the capacity of quenching hydroxy radicals （·OH ） the salicylic acid quenching method and the malondialdehyde （MDA） formation method and the identification method of CuSO4- Phen- VC-H2O2 DNA system were used. The results showed that Rhodiola sacra could minimize the formation of intermediate product of pyrogallol , inhibited to a certain extent the chemiluminescence induced by X-XO-L system the half scavenge （IC50） of the content of hydroxyl radicals generated by the salicylic acid method, was 130μg/ml . When the concentration of the Rhodiola sacra extract was 300μg/ml determined by MDA method, in the system, the inhibition of ·OH generation reached the highest extent. In the CuSO4-Phen-VC-H2O2 system, the peak of chemiluminescence of DNA damage product lowered and delayed as the administration of Rhodiola sacra extract increased. Summing up all these evidences, it might be conclude that Rhodiola sacra possess the capacity of scavenging free radicals of O2-·and ·OH.

Key words: Rhodiola sacra, in vitro anti-oxidative activity, free radicals