Cardioprotective activity of Amaranthus viridis Linn: Effect on serum marker enzymes, cardiac troponin and antioxidant system in experimental myocardial infarcted rats

Background: Cardiovascular diseases (CVDs) have a high prevalence in developing and developed countries and myocardial infarction accounts for majority of deaths and disabilities. The current study dealt with the protective role of Amaranthus viridis Linn on isoproterenol (ISO)-induced myocardial infarction (MI) in rats. Methods: Subcutaneous injection of ISO (20 mg/kg body weight in 1 ml saline) to rats for two consecutive days offered significant alteration in cardiac marker enzymes (AST, ALT, LDH and CPK), cardiac troponin, lipid peroxidation products (TBARS and hydroperoxide) and antioxidant system (CAT, SOD, GPx, GST, GSH and GSSG). ISO-induced myocardial damage was indicated by increased activities of marker enzymes in serum and the levels of cardiac troponin in the serum. In addition to these diagnostic markers, the levels of lipid peroxidation products in the heart were significantly (p<0.05) increased and the activities of enzymic antioxidants and non-enzymic antioxidant such as glutathione in the heart was significantly (p<0.05) decreased and GSSG in the heart was increased in ISO-induced rats. Results: Effect of Amaranthus viridis oral treatment (100, 200 and 300 mg/kg body weight) for 45 days elicited a significant cardio protective activity by lowering the levels of serum marker enzymes, cardiac troponin, GSSG and lipid peroxidation and elevated the levels of antioxidant enzymes and GSH. The effect at a dose of 300 mg/kg of A. viridis was more pronounced than that of the dose 100 mg/kg and 200 mg/kg and brought back all the parameters to near normal. The effect produced by A. viridis was compared with alpha-tocopherol. Conclusions: The present findings have demonstrated that the cardioprotective effects of A. viridis in ISO-induced oxidative damage may be due to an augmentation of the endogenous antioxidants and inhibition of lipid peroxidation of membrane. (c) 2011 Elsevier Ireland Ltd. All rights reserved.