RESUMEN
INTRODUCTION: This study was designed to scientifically evaluate the effects of an aqueous extract of Muntingia calabura L. (M. calabura), a medicinal herb, on isoproterenol-induced myocardial infarction (MI) in rat models. METHODS: Six groups of Wistar albino rats, each comprising six animals, were selected for this study. Group I served as a control, Group II rats were given isoproterenol (20 mg/100g, subcutaneously), and Group III rats were given M. calabura leaf extract (300 mg/kg). Groups IV, V and VI rats were given M. calabura leaf extract (100 mg/kg, 200 mg/kg and 300 mg/kg, respectively) and isoproterenol (20 mg/100g subcutaneously) prior to MI induction. The transaminases (aspartate transaminase and alanine transaminase), lactate dehydrogenase (LDH) and creatine phosphokinase (CK), were estimated in both the serum and heart tissues, and the serum uric acid level was also estimated. RESULTS: Isoproterenol significantly increased the activities of CK, LDH and the transaminases in serum with a concomitant decrease in these enzymes in tissue. Pretreatment with the aqueous leaf extract of M. calabura at a dose of 300 mg/kg body weight for 30 days had a significant effect on the activities of marker enzymes compared to the other groups. Serum uric acid level, which increased on isoproterenol administration, registered near normal values on treatment with the leaf extract under study. CONCLUSION: The study confirms the protective effects of M. calabura leaf extract against isoproterenol-induced biochemical alterations in rats.