ORIGINAL PAPER Morin protects heart from beta-adrenergic-stimulated myocardial infarction: an electrocardiographic, biochemical, and histological study in rats Bharath Kumar Pogula & Mari Kannan Maharajan & Divya Rekha Oddepalli & Lavanya Boini & Mounika Arella & Darlin Quine Sabarimuthu Received: 2 August 2011 / Accepted: 15 February 2012 / Published online: 15 March 2012 # University of Navarra 2012 Abstract In recent years, polyphenols have attracted considerable attention as agents that protect cells or molecules from oxidative myocardial injury. The aim of the study was to prove the cardioprotective benefits of the flavonoid morin in isoproterenol-induced myo- cardial infarcted rats. Male Wistar rats are treated orally with morin (10 and 20 mg/kg) daily for a period of 21 days. After 21 days of pretreatment, isoprotere- nol (100 mg/kg) was injected subcutaneously to rats at an interval of 24 h for 2 days to induce myocardial infarction. Electrocardiographical abnormalities and biomarkers were measured in normal and experimental rats. Isoproterenol-induced myocardial infarcted rats showed significant (p <0.05) increase in the levels of cardiac markers. Pretreatment with morin regulated the abnormalities in electrocardiograph and biomarkers. The lipid peroxidation products were increased and indicated the increased lipid peroxidation in isoproterenol-induced myocardial infarcted rats. The rats pretreated with morin significantly reduced lipid peroxidation. The altered lipid metabolism was observed in isoproterenol-induced myo- cardial infarcted rats and in pretreatment with morin- regulated lipid metabolism. Histopathological study evidenced that the pretreatment with morin inhibited myocardial damage. The results of this study proved the protective effect of morin as pretreatment and are rational to understand the beneficial effects of morin on cardioprotection against myocardial injury. Based on the results, the cardioprotective ability of morin on human beings can be studied in the future. Keywords Morin . Isoproterenol . Electrocardiogram . Lipid peroxidation . Lipid profile . Histopathology Introduction Coronary artery diseases (CAD) are the most prevalent cause of death and disability worldwide. CAD is a con- dition in which the vascular supply to the heart is imped- ed and causes ischemia. A prolonged ischemia may cause the death of cardiomyocytes, i.e., myocardial in- farction (MI). It means, occlusion in the coronary artery J Physiol Biochem (2012) 68:433–446 DOI 10.1007/s13105-012-0157-z B. Pogula : D. Oddepalli : L. Boini : M. Arella Department of Clinical Pharmacy and Pharmacology, Jayamukhi College of Pharmacy, Narsampet, Warangal, Andhra Pradesh, India M. Maharajan (*) Department of Pharmacy Practice and Clinical Pharmacy, Sri Padmavathi School of Pharmacy, Tiruchanoor, Tirupati, Andhra Pradesh, India e-mail: kanpharm2002@gmail.com D. Sabarimuthu Post Graduate and Research Department of Chemistry, Government Arts College, C.Mutlur, Chidambaram, Tamil Nadu, India