CARDIOPROTECTIVE ACTIVITY OF POLYALTHIA SUBEROSA AGAINST ISOPROTERENOL INDUCED MYOCARDIAL INFARCTION IN ALBINO WISTAR RATS

Abstract

The present study was carried out to evaluate the Cardio protective activity of leaf extract of Polyalthia suberosa against Isoproterenol (ISO) induced Myocardial Infarction (MI). ISO-induced myocardial ischemia is considered as one of the most widely used experimental model to study the beneficial effects of many drugs on cardiac function. Polyalthia suberosa is used in the indigenous system of medicine as an antioxidant. However, there are no reports available in literature on its traditional use in MI. In the present study, an increase in LDH1 isoenzyme band in ISO myocardial infarcted rats was observed. The results showed a significant increase of serum CK-MB and LDH levels in ischemic control when compared with normal group. Different doses (200 mg/kg and 400 mg/kg) of plant extract treated groups have shown significant and dose dependent decrease in serum CK-MB and LDH levels when compared with ischemic control group.

The increased activities of these enzymes following injection of ISO as observed in this study confirmed the onset of myocardial necrosis. Pretreatment with leaf extract of Polyalthia suberosa lowered the elevated levels of enzymes compared to the control. This is an indication of the protective action of the extract in reversing cardiac damage due to isoproterenol. ISO induced MI had been shown to elevate plasma TC, TG, LDL and decrease HDL levels. Also higher level of LDL has a positive correlation whereas, high level of HDL has a negative correlation with MI. Histopathological studies of cardiac tissue in ISO group showed the presence of focal myo necrosis with myo phagocytosis and lymphocytic infiltration in sub-endocardial region indicative of infract like lesions. Scrutiny of cardiac tissue of ISO + MEPS group shows significant and dose dependent reduction in myonecrosis and lymphocyte infiltration than ISO group. Moreover as the plant possesses flavonoids the cardio protective activity may be due to presence of flavonoids.

Hence, it can be summarized that MEPS pre-treatment to ISO treated rats provide cardio protection by inhibiting the formation of free radicals generated during oxidation of catecholamine thus inhibiting peroxidation of membrane lipids and preventing subsequent leakage of soluble enzymes. Also, Polyalthia suberosa pre-treatment appears to be instrumental in preventing oxidation of –SH group of cardiac ATP ases and improvement in status of enzymatic and non-enzymatic antioxidants that further contributes to its overall cardio protective property.

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