Effect of acetone extract of Rumex japonicas Houtt on hydrogen peroxide-induced apoptosis in rat myocardial cells

Purpose: To investigate the protective effect of the acetone extract of Rumex japonicas Houtt. (AER) on rat myocardial cells. Methods: R. japonicas was extracted with 75 % aqueous ethanol by reflux to afford total extract (TER). TER was suspended in water and then extracted with acetone to afford acetone fraction of R. japonicas (AER). High performance liquid chromatography (HPLC) combined with standard substances was carried out to analyze the major constituents of AER. Apoptosis in myocardial H9c2 cell line was induced by H2O2 (100 mu mol/L). The cells were treated with AER (50, 100 and 200 mu g/mL, and cell viability was evaluated by the 3- (4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay, while oxidative stress level in H9c2 cells was evaluated by determining levels of lactate dehydrogenase (LDH), malondialdehyde (MDA), creatinine kinase (CK), superoxide dismutase (SOD), and catalase (CAT). Furthermore, apoptotic proteins (caspase-3, Bax and Bcl-2) in H9c2 cells were analyzed by using western blot assay. Results: Results revealed that the main components of AER are aloe-emodin, rhein, emodin, chrysophanol and physcion. AER (50, 100 and 200 mu g/mL) inhibited the cell viability reduction of the H9c2 cells induced by H2O2 (p < 0.05, p < 0.01, p < 0.01, respectively). AER (50, 100 and 200 mu g/mL) decreased LDH and CK contents of H9c2 cells (p < 0.01). The levels of SOD (p< 0.01) and CAT (p < 0.01) were increased by AER treatments (100 and 200 mu g/mL); in addition, AER (50, 100 and 200 mu g/mL) decreased MDA levels (p < 0.01). Besides, the present results also revealed that AER could down-regulate caspase-3 and Bax, but up-regulated Bcl-2. Conclusion: AER alleviates apoptosis induced by H2O2 in myocardial H9c2 cells via inhibition of oxidative stress and mitochondria-mediated apoptosis. This finding suggests that AER can potentially be developed for the treatment of myocardial apoptosis.