OBJECTIVE:To investigate the efficacy of water fraction from Dioscorea cirrhosa(WF)on oxidative damage and apoptosis of cardiomyocytes induced by H2O2,and to study its mechanism.METHODS:Cell viability was measured by the MST assay kit.The content of malondialdehyde(MDA),release of lactate dehydrogenase(LDH)and activity of catalase(CAT)and superoxide dismutase(SOD)were detected by biochemical kit.The content of reactive oxygen species(ROS)was assessed by non-fluorescent probe 2',7'-dichlorofluorescin diace-tate(DCFH-DA).JC-1 was used to analyze the mito-chondrial membrane potential(mtΔψ)and Annex-in-V-FITC/PI staining was applied to assess apopto-sis of H9c2 by flow cytometry.Moreover,the expres-sion of B-cell lymphoma-2(Bcl-2),Bcl-2-associated X(Bax),caspase-3,caspase-9,cleaved-caspase-3 and cleaved-caspase-9 proteins was determined by western blot analysis.RESULTS:WF increased cell viability and decreased LDH leakage in H9c2 cells exposed to H2O2.WF treatment decreased ROS and MDA level,en-hanced SOD and CAT activities,improved mtΔψand inhibited apoptosis.Western blot analysis dem-onstrated that the ratio of Bcl-2/Bax was increased and the expression cleaved-caspase-3,caspase-3,cleaved-caspase-9 and caspase-9 were decreased in group treated with WF.CONCLUSION:WF protects H9c2 myocardial cells on H2O2-induced oxidative stress and apoptosis by scavenging ROS,improving antioxidant capacity,protecting mitochondrial and regulating the pro-teins expression related to apoptosis.