Abstract: H9c2 cardiomyocytes were treated with different concentrations of H₂O₂.The effect of Compound Longmaining (CLMN) water extract and alcohol extract (5%,10%,20% group) on H9c2 cardiomyocytes injured by H₂O₂ was detected by MTT assay.The results showed that a stable H9c2 cardiomyocytes injury model can be established when the concentration of H₂O₂ was 100 μM and the action time was 24 h.Compared with the control group,the activity of the cells decreased obviously after treatment with H₂O₂,and the activity of SOD decreased significantly,but the activity of LDH and the content of MDA increased significantly.While CLMN water extract and ethanol extract serum containing drugs (10%,20% groups) can significantly improve cell viability and SOD activity,as well as reduce LDH activity and MDA content.The results indicated that CLMN water extract and ethanol extract can protect H9c2 cells from oxidative injury induced by H₂O₂.

Key words: CLMN extract, H9c2 cardiomyocytes, MTT method, myocardial oxidative injury