Cardioprotective effect of Bacopa monneira against isoproterenol-induced myocardial necrosis in rats

The effects of standardized hydro-alcoholic lyophilized extract of Bacopa monneira (Bm) in isoproterenol (ISP)-induced myocardial necrosis were studied. Wistar albino male rats were randomly divided to sham, ISP control and Bacopa monneira treated groups. Bacopa monneira was administered in doses of 50, 100, 150 or 200 mg kg^-1 orally for 30 days to Bacopa monneira treated groups while sham and ISP control groups received saline orally for the same duration. On day 29 and 30, ISP (85 mg kg^-1) was administered subcutaneously at an interval, of 24 h to ISP control and Bacopa monneira treated groups. On day 31, hemodynamic parameters were recorded before all rats were sacrificed. Hearts were excised and processed for biochemical, histopathological and ultrastructural assessment. Significant cardiac dysfunction, decline in endogenous antioxidant defence [superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSBPx) and reduced glutathione (GSH)], myocyte specific injury markers [myocardial lactate dehydrogenase (LDH) and creatine kinase-MB (CK-MB) isoenzyme] as well as increase in lipid peroxidation marker [malonaldialdehyde (MDA)] were observed in ISP control group as compared to sham control. Of the different doses studied, Bacopa monneira (150 mg kg^-1) produced maximum cardioprotection as evidenced by significant restoration of endogenous antioxidants, myocardial LDH and CK-MB isoenzyme activities and decrease in MDA. Histopathological and ultrastructural findings also reconfirmed the cardioprotective effect of the extract. The significance of these results is discussed in relation to cardioprotective effects of Bacopa monneira against ISP-induced cardiotoxicity.