Abstract

This study was designed to investigate the preventive effect of ethanolic extract ofRhododendron arboretum (ERA) against isoproterenol-induced myocardial ischemia in rat myocardium. Wister rats were pretreated with ERA (100, 250, 500 mg kg^-1) orally for 42 days and then intoxicated with isoproterenol (ISO, 150mg/kg body weight, s.c. for 2 days). MI induced in rats by subcutaneous injection of ISO-(150 mg/kg body weight) at interval of 24 h for 2 days showed significant elevation in serum cardiac marker enzymes like lactate dehydrogenase (LDH), aspartate transaminase (AST) and alanine transaminase (ALT). Lipid peroxidative product like lipid hydroperoxidase was elevated in tissue and serum, decline in enzymatic antioxidant status (superoxide dismutase, catalase, glutathione peroxidase) and non-enzymatic reduced glutathione antioxidants. Pretreatment with ERA to ISO-treated rats caused a significant protective effect. Administration of ERA in normal rats did not have any significant effect on cardiac markers, lipid peroxidation and antioxidant levels. The results of our study show that ERA possesses protective effect result from suppression of oxidative stress in ISO-induced myocardial infracted rats. Histopathological examination further confirmed the cardioprotective effect of ERA against ischemic insult.

Key words: Myocardial infarction, isoproterenol, antioxidants, Rhododendron arboreum, oxidative stress.