Abstract: 26 healthy volunteer undergraduates were selected to observe the anti-oxidative effect of daidzein under fatigue-stress, with the method of the gradual-loading-exercise. The results showed that, after exercising, the activities of CAT, GSH-Px, SOD and the content of MDA in the control group increased, and the change of the activity of GSH-Px was significant (p<0.05). In the daidzein group, the activities of three kinds of anti-oxidases all increased after exercising, and were higher than those of the control group. The activities of GSH-Px and SOD after exercising increased significantly compared with those before taking daidzein (p<0.05 or p<0.01) and the activity of SOD increased significantly compared with that after taking daidzein (p< 0.05). The content of MDA of the daidzein group increased little after exercising, and was lower than that of the control group. These results indicated that daidzein could improve the anti-oxidative ability and reduce the level of MDA under fatigue-stress and thus enhance the anti-stress ability.

Key words: daidzein, fatigue stress, anti-oxidase, malondialdehyde ( MDA )