Marrubium vulgare L. methanolic extract inhibits inflammatory response and prevents cardiomyocyte fibrosis in isoproterenol-induced acute myocardial infarction in rats

Introduction: Nowadays, finding new therapeutic compounds from natural products for treatment and prevention of a variety of diseases including cardiovascular disorders is getting a great deal of attention. This approach would result in finding new drugs which are more effective and have fewer side effects than the conventional medicines. The present study was designed to investigate the anti-inflammatory effect of the methanolic extract of Marrubiumvulgare, a popular traditional medicinal herb, on isoproterenol-induced myocardial infarction (MI) in rat model. Methods: Male Wistar rats were assigned to 6 groups of control, sham, isoproterenol, and treatment with 10, 20, and 40 mg/kg/12h of the extract given orally concurrent with MI induction. A subcutaneous injection of isoproterenol (100 mg/kg/day) for two consecutive days was used to induce MI. Then, histopathological changes and inflammatory markers were evaluated. Results: Isoproterenol injection increased inflammatory response, as shown by a significant increase in peripheral neutrophil count, myocardial myeloperoxidase (MPO) activity and serum levels of creatinine kinase-MB (CK-MB) and TNF-α (p<0.001). In the groups treated with 10, 20 and 40 mg/kg of M.vulgare extract serum CK-MB was subsided by 55.4%, 52.2% and 69%, respectively. Also treatment with the extract (40 mg/kg) significantly reduced (p<0.001) MPO activity in MI group. The levels of TNF-α was also considerably declined in the serums of MI group (p<0.001). In addition, peripheral neutrophil count, was significantly lowered by all doses of the extract (p<0.001). Interstitial fibrosis significantly was attenuated in treated groups compared with control MI group. Conclusion: The results of study demonstrate that the M. vulgare extract has strong protective effects against isoproterenol-induced myocardial infarction and it seems possible that this protection is due to its anti-inflammatory effects.