Cardioprotective Effects of the Ethanol Leaf Extract of Andrographis Paniculata in Isoproterenol‐induced Myocardial Infarction in Rats

Abstract

Andrographis paniculata commonly known as king of bitters is an annual ‐ branched, erect ‐ running 1/2 to 1 meter in height. The aerial parts of the plant (leaves and stems) are used to extract the active phytochemicals. It grows abundantly in south eastern Asia: India (and Sri Lanka), Pakistan and Indonesia ‐ but it is cultivated extensively in China and Thailand, the East and West Indies, and Mauritius. Modern pharmacological studies have demonstrated its hepatoprotective, antithrombotic, anti‐inflammatory, immunostimulant, antimalarial, antihyperglycemic and cardioprotective properties. Because of its well‐known medicinal properties, this study was designed to evaluate the cardioprotective effect of the Nigerian species of Andrographis paniculata (AP) ethanol leaf extracts in isoproterenol‐induced myocardial infarction in rats using electrocardiogram, blood pressure changes as well as anti‐oxidant status.Male rats were randomly divided into 7 groups of 7 animals per group. While group A served as control, group B was administered with Isoproterenol (ISO), group C was administered with Enalapril (10 mg/kg), but groups D, E and F were pretreated respectively with EEAP in three different doses (100, 200 and 400 mg/kg) orally for 7 days and group G was administered with 200 mg/kg EEAP post treatment with ISO. Myocardial infarction was induced intraperitoneally (i.p.) using isoproterenol (85 mg/kg) at interval of 24 h on 8th & 9th day in pretreated groups while on 1st & 2nd day in post treated group. The electrocardiogram, heart rate and blood pressure measurements were carried out on the 10th day in all groups and all animals were sacrificed afterwards and heart tissues were collected, homogenized, and centrifuged for anti‐oxidant studies.ISO injection (85 mg/kg i.p.) produced changes in ECG pattern including prolonged QT interval and notches. ISO injection also produced a significant decrease in SAP, DAP and MAP levels. Although the extract did not amend the changes in ECG to normal but significantly increased the hemodynamics parameters. The extract increased antioxidant enzymes (SOD, GPX, GST, and GSH) and reduced oxidative stress markers (MDA using lipid peroxidation, H2O2, PT and NPT).It could be concluded that the ethanol leaf extract of Andrographis paniculata exhibited cardioprotective effect in rats showing potent anti‐oxidant properties as well as improving the haemodynamic changes in the rats. This cardioprotective effect was similar to that of enalapril, an ACE inhibitor used in this study.Support or Funding InformationNational Research Foundation of the Tertiary Research Fund, Nigeria.