Abstract: AIM: To explore the effects of active in-gredient of soybean isoflavones on PC12 cells injuries in-duced by H₂O₂. METHODS: Active ingredients of soy-bean were extracted and purified.PC12 cells cultured in vitro was pretreated by different dosage of the ingredients about 12 hours and then injured by H₂O₂ (10 mmol°L^-1). Cell viability rate in all groups was tested by MTT assay. Activity of LDH of all groupswas tested. RESULTS: The viability rates in all groups pretreated was significantly increased compared with only H₂O₂ treat-ment group (P<0.05). The activity of LDH in all pre-treatment group was significantly decreased (P<0.05) compared with H₂O₂ treatment group.CONCLUSION: Active ingredient of soybean isoflavoneson can restrain cy-totoxicity induced by H₂O₂ and protect cells from peroxy-dation.

Key words: H₂O₂, PC12, soybean isoflavones, cell injury, Alzheimers disease