Cardio-Protective Effect of the Leaf Extract of Andrographis paniculata in Isoproterenol-Induced Myocardial Infarction

Background: Nowadays, myocardial infarction has been regarded as one of the chronic diseases with increasing mortality rate worldwide. The use of medicinal plants in the treatment of this chronic disease is gaining wide acceptance globally. 
 Materials and Methods: This study was carried out to evaluate the cardio-protective effect of the leaf extract of A. paniculata in isoproterenol-induced myocardial infarction. Fresh green leaves of A paniculata were collected from the Faculty of Agriculture farmland, Nnamdi Azikiwe University, Awka, Nigeria. The plant was identified and authenticated at the Department of Botany, Nnamdi Azikiwe University and a voucher specimen was deposited at the herbarium accordingly. The shredded, air-dried sample was then pulverized and weighed. Solvent-solvent (ethanol and water) (7:3) was used for extraction via maceration for 72 hr. The filtrate was evaporated to dryness to obtain the ethanol extract which was used for further bioassay study. The bioactive constituents of the plant extract were quantitatively analyzed by Gas chromatography mass spectrometry (GC-MS). The animals were administered with the extract of A. paniculata orally for seven days at a divided dose of 100 mg/kg, 200 mg/kg and 400 mg/kg body weights. On the eight day, myocardial infarction was induced through subcutaneous administration of isoproterenol at a dose of 150 mg/kg/day diluted in 2 ml of saline on two consecutive days. Subsequently, the blood pressures were monitored and blood collected for bioassay studies. 
Results: The results of the study showed that the leaf extract of A. paniculata was rich in 2,5-Octadecadiynoic acid, methyl ester (28.21%); 1,2,3,5-Cyclohexanetetrol,(1à,2á,3à,5á)- (15.10 %) and 10-12-Pentacosadiynoic acid (13.05%). The findings also showed a significant decrease (p>0.05) in the Mean arterial blood pressure, heart rate, aspartate transaminase, alanine transaminase, creatinine kinase and lactate dehydrogenase activities of the treatment group compared with the untreated control group while the antioxidant (superoxide dismutase, catalase and glutathione) activities were significantly increased in the treatment group, compared with the untreated control group. 
Conclusion: The findings of this work have shown that leaf of A. paniculata was rich in bioactive compounds which could be synthesized to produce plant based products to combat cardiovascular diseases especially myocardial infarction.