Protective Effect of Piper longum Fruits against Experimental Myocardial Oxidative Stress Induced Injury in Rats

The present study investigated the protective effect of methanolic extract of fruits of Piper longum L. (PLM) on isoproterenol (ISO) induced myocardial infarction in rats. PLM was administered to Wistar albino rats in two different doses, by gastric gavage for 28 days. Myocardial infarction was induced by subcutaneous administration of ISO for 2 days at the end of the dosing period. ISO administration resulted in significant decrease in the activities of marker enzymes aspartate transaminase (AST), alanine transaminase (ALT), lactate dehydrogenase (LDH) and creatine kinase (CK) in heart with a concomitant increase in their activities in serum. A significant increase in lipid peroxide levels (TBARS) in hearts of ISO-induced rats was also observed. Activities of myocardial antioxidant enzymes like catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPOX) and glutathione reductase (GR) along with reduced glutathione (GSH) were significantly lowered owing to myocardial infarction in ISO treated rats. PLM pretreatment was found to ameliorate the effect of ISO on lipid peroxide formation and retained activities of marker enzymes. It also prevented ISO-induced decrease in antioxidant enzymes in the heart. The histopathological studies of heart revealed a protective role PLM in ISO treated rats. The results exhibited that the pretreatment with methanolic extract of Piper longum fruits may be useful in preventing the damage induced by ISO in rat heart.