Abstract: Mice were used as the models of our experiment.After weaning and under sane feedibng, 2aroups of mice were given ordinary water and 50% sogittaria agittifolia juice for 36 days (the earlyaged stage) and 110 days (the middle-aged stage) respectively.The SOD activity, contents of MDA and lipofuscin of the liver and brain homogenate were measured.The results showed that the SOD activity of the 3iver and brain hmpenate in the Sagittaria agittifolia group increased significontly at the early-aged (p<0. 05) and more significantly at the middle-aged (p<0 .01) .The content of lipofuscin and MDA in the brain homogenate had no change at the early-aged of the two groups,but the content was much lower in the Sagittaria agittifolia group than that of the control group at the middle-aged (p<0. 01) .However the content of lipofuscin of liver homogenate and MDA had no obvious change at different ages. According to the current consensus that the oxidation operated at DNA level, the mice of 110, 150 and 180 days respectively were selected for spleen suspension culture .With the same culture solution, 240 umol/L Sagittaria agittifolia were added to the trial group.Afterirradiation with UV,3H-TdR incorporation test was carried out of measure the ability of DNA repair. The measurenent displcyed that DNA repair ability decreased with age, but DNA repair ability was obviously higher in Sagittaria agittifolia group than that of the contr0l qroup (p<0 .01 ) .The resulf suggested that Sagittaria agittifolia had the effect of antioxidation deladyed aqing and acted on DNA level as well.

Key words: Sagittaria agittifolia Antioxidation DNA repair Mice