Dracocephalum moldavica L. Extracts Protect H9c2 Cardiomyocytes against H2O2-Induced Apoptosis and Oxidative Stress

Background and Objectives. Dracocephalum moldavica L. is an herbal medicine used to treat cardiovascular diseases in China. The purpose of this study was to assess the cardioprotective effect of D. moldavica L. extracts against H2O2-induced apoptosis and oxidative stress in H9c2 cells and to explore the mechanism behind this effect. Materials and Methods. The petroleum ether (petrol), dichloromethane (CH2Cl2), ethyl acetate (EtOAc), and n-butyl alcohol (n-BuOH) fractions were isolated from alcohol extracts of D. moldavica L. Total phenolic and flavonoid contents and in vitro antioxidant activities of different fractions were evaluated. H9c2 cells were then treated with D. moldavica L. extracts before challenging with H2O2. Cell viability was determined by colorimetric assay, and ELISA was used to measure the levels of lactate dehydrogenase (LDH), malondialdehyde (MDA), and superoxide dismutase (SOD). Apoptosis levels and mitochondrial membrane potential were measured by flow cytometry. The expressions of cell apoptosis regulatory proteins caspase-3, Bax, and Bcl-2 were determined by western blotting. Results. Our results demonstrated that the EtOAc fraction from D. moldavica L. ethanol extract, which is rich in phenolic and flavonoid active constituents, had the strongest free radical scavenging activity. Additionally, this fraction increased H2O2-induced reduction in cell viability, SOD activity, and mitochondrial membrane potential. It also reduced H2O2-induced elevation in ROS production, contents of LDH and MDA, and H9c2 apoptosis. We further found that the EtOAc fraction increased Bcl-2 expression, while it decreased caspase-3 and Bax expressions induced by H2O2 in H9c2 cells. Conclusions. Our data revealed that the EtOAc fraction from D. moldavica L. ethanol extract ameliorates H2O2-induced cardiotoxicity via antiapoptotic and antioxidant mechanisms.