Vivek et al. | Int. J. Res. Phytochem. Pharmacol. 2011, 1(1), 28-32 28 ©JK Welfare & Pharmascope Foundation | International Journal of Research in Phytochemistry & Pharmacology Cardioprotective activity of shilajit in isoproterenol - induced myo- cardial infarction in rats: A biochemical and histopathological evaluation B.Vivek* 1 , E. Wilson 2 , S.V. Nithya Devi 3 , C. Velmurugan 1 , M. Kannan 4 1 Department of Pharmacology, Sri K.V College of Pharmacy, M.G Road, Chickballapur. KA, India 2 SRF, National Institute of Indian Medical Heritage, Hyderabad, India 3 Department of Pharmacoinformatics, Sarojini Naidu Vanitha Pharmacy Maha Vidyalalayam, Nampally, Hydera- bad, India 4 Department of Pharmacology, PRIST University, Thanjavur, Tamil Nadu, India ABSTRACT The cardioprotective effects of shilajit in isoproterenol (ISO) induced cardiotoxicity and the antioxidant activity involved in this protection were investigated in rats. Myocardial infarction was produced in rats with 65, 85, 120 and 200 mg/kg of ISO administered subcutaneously (sc) twice at an interval of 24 h. ISO at the dose of 85 mg/kg was selected for the present study as this dose offered significant alteration in biochemical parameters and moderate necrosis in heart. Effect of shilajit oral pretreatment for 91 days at two different doses (250 & 500mg/kg body weight) were evaluated against ISO (85 mg/kg, sc) induced cardiac necrosis. Levels of marker enzymes such as serum glutamic-oxaloacetic transaminase (SGOT), serum glutamic-pyruvic transaminase (SGPT), Lactate dehydrogenase (LDH) and creatinine kinase (CK) were assessed in serum and heart homogenate, other biochemical parameters viz., reduced glutathione (GSH), Lipid Hydro Peroxide (LHP), Lipid per oxidase (LPO) were also assayed in serum and heart homogenate. Significant myocardial necrosis, depletion of endogenous antioxidants and increase in serum levels of marker enzymes were observed in ISO-treated animals when compared with the normal animals. Shilajit elicited a significant cardioprotective activity by lowering the levels of serum marker enzymes and lipid peroxidation and elevated the levels of GSH. The present findings have demonstrated that the cardioprotective effects of Shilajit in ISO-induced oxidative damage may be due to an augmentation of the endogenous antioxidants and inhibition of lipid peroxidation of membrane. Keywords: Cardiac markers; cardiotoxicity; myocardial infarction; isoproterenol; ischemia; shilajit INTRODUCTION Myocardial infarction (MI) is the acute condition of necrosis of the myocardium that occurs as a result of imbalance between coronary blood supply and myo- cardial demand (Boudina et al., 2003). It is well recog- nized that there is increasing generation of reactive oxygen species such as superoxide anion and hydroxyl radicals and other reactive species in ischemic tissue, bringing about oxidative damage of membrane lipids, proteins, carbohydrates and DNA (Dikshit et al., 1992). Isoproterenol (ISO), a synthetic catecholamine and β adrenergic agonist is documented to produce MI in large doses due to generation of highly cytotoxic free radicals through its auto-oxidation (Rona et al., 1959). These free radicals stimulate lipid peroxidation and cause irreversible damage to the myocardial mem- brane. The Shilajit, traditional system of medicine has treated heart diseases with a wide range of medicine for ages (Bharatiya Rasashastra, 2004, Ghosal et al., 1989). Shilajit is very useful in many diseases and serves as a potent tonic. Traditionally, it is also consi- dered to increase virility and in Ayurvedic medicine system of India, it is used against various diseases. (Dash B., 1991). Shilajit’s usage in pre-historic Indus civilization period has been well documented (Nadkar- ni, 1954). The present study has been designed to eva- luate the cardioprotective activity of shilajit in ISO- induced cardiac damage in rats and attempts to under- stand the molecular mechanism of its therapeutic ef- fect with reference to biochemical markers and anti- oxidant enzymes, lipid peroxidation and histological examination. MATERIALS AND METHODS Drugs and chemicals Shilajit Powder Extract 3% was obtained from Dhan- vantari Botanicals Pvt Ltd, Bangalore, India. Reduced glutathione, oxidized glutathione and NADPH were obtained from Himedia Laboratories, Mumbai, India. 5, 5-Dithiobis (2-nitrobenzoic acid) (DTNB), ISO was pur- www.ijrpp.pharmascope.org Research Article * Corresponding Author Email: vivekpharmacology@gmail.com Contact: +91-8050796811 Received on: 06-12-2010 Revised on: 10-12-2010 Accepted on: 16-12-2010