The present study was designed to evaluate the cardioprotective role of Poly herbal formulation (PHF) extract on isoproterenol induced myocardial infarction in Wistar albino rats. The rats were divided into eight groups of six animals each. Group I served as a normal control, Group II rats were administered isoproterenol (20 mg/g B.wt). Group III and IV were pretreated with PH extract (250 mg/kg B.wt, 500 mg/kg B.wt, respectively) and received a subcutaneous injection of isoproterenol (20 mg/kg, B.wt) at the end of the experimental period for 2 consecutive days. Group V and VI were pretreated orally with Propranolol (10 mg/kg B.wt, 20 mg/kg B.wt) and received a subcutaneous injection of isoproterenol (20 mg/kg, B.wt) at the end of the experimental period of 2 consecutive days. Group VII and VIII received PH extract of 250 mg/kg B.wt and 500 mg/kg B.wt for 30 days and were studied on the enzymes of TCA cycle, such as isocitrate dehydrogenase, succinate dehydrogenase, malate dehydrogenase, and α-ketoglutarate dehydrogenase and respiratory chain enzymes such as NADH dehydrogenase along with histopathological observation. Isoproterenol induction also showed significant (p<0.05) decrease in the activities of mitochondrial TCA cycle enzymes such as isocitrate dehydrogenase, succinate dehydrogenase, malate dehydrogenase, and α-ketoglutarate dehydrogenase and respiratory chain enzymes such as NADH dehydrogenase. The PH crude extract produced a significant (p<0.05) increase in the TCA cycle enzymes in heart tissue homogenate. The PH crude extract showed a significant (p<0.05) improvement in the treated groups. The effect of oral administration of the PH crude extract at the dose of 500 mg/kg B.wt was more than 250 mg/kg B.wt. Similarly the standard drug propranolol treated group 20 mg/kg B.wt also showed a better result. As further confirmed histopathologically, our findings strongly suggest that the cardioprotective effect of the PH crude extract on the myocardium. This result indicates that the PH crude extract exhibit the cardioprotective activity and the protective effect could attribute to its TCA cycle enzyme action.
Sudhakar Monisha, Marimuthu Ramar, Balliah Ragavan, Pandian Manonmani and Ponnan Arumugam