Protective action of aqueous leaf extract of Gazania krebsiana (Less.) ‘Asteraceae’ antagonizes isoproterenol-triggered myocardial infarction in Rattus norvegicus

Gazania krebsiana (Less.) is employed traditionally as treatment in the Basotho Traditional medicine in the management of numerous ailments. The study evaluated the cardioprotective action of aqueous leaves extracts of G. krebsiana (ALEGK) against cardiotoxicity induced by isoproterenol hydrochloride (ISP). ISP (1 mL; 60 mg kg⁻¹ BW) dissolved in 0.9% sodium chloride was used to induce myocardial damage intraperitoneally in the experimental animals. The outcomes of pre-treatment with 1 mL of the doses (125, 250, and 500 mg kg⁻¹ BW) of ALEGK on consumed food, water intake, body-organ weight ratio, biochemical parameters including aspartate aminotransferase (AST), alanine transaminase (ALT), creatine phosphokinase (CPK), catalase (CAT), glutathione peroxidase (GPx), and lipid peroxidation were studied during the 30-day investigational span. ISP-induced rats revealed no statistical (P > 0.05) effect on the appetite and body weight of the animals yet remarkably (P < 0.05) increased the activities of AST, CPK, ALT, and lipid peroxidation with concurrent reduction in CAT and GPx activities. Pre-treatment with ALEGK at different doses appreciably (P < 0.05) extenuated the raised activities of the serum cardiac (CPK) and liver (ALT, AST) enzymes with concomitant restoration to normal the reduced activities of antioxidant enzymes and cardiac lipid peroxidation. Histological appraisal of the heart tissues revealed granulocyte infiltration, sarcolemma nucleus proliferation as well as interstitial inflammation for ISP-treated rats. However, treatment with ALEGK especially at 500 mg/kg⁻¹ ameliorated these alterations suggesting its maximum effectiveness against ISP-induced cardiotoxicity. This investigation confirmed the cardioprotective potential of ALEGK against ISP-induced myocardial injury sequel to the established outcome of the study.