Cardioprotective Potential of d-limonene against Isoproterenol induced Myocardial Infarction in Rats

d-limonene is a type of colorless liquid hydrocarbon that falls under the category of cyclic monoterpene. It is the component found in the oil extracted from fruit peels. Isoproterenol, a synthetic β-adrenergic agonist, was administered to rats to induce myocardial injury by increasing heart rate and myocardial oxygen demand, leading to ischemia and oxidative stress. This study aims to investigate the properties of d limonene, against myocardial infarction induced by isoprenaline (ISO) in rats. Male Sprague Dawley rats were treated with d-limonene (200 & 400 mg/kg, p.o) daily for 28 days and administered ISO (85 mg/kg, s.c) on the 29th and 30th days at an interval of 24 hr to induce myocardial injury. Morphological and antioxidant parameters, biochemical markers, lipid profile, troponin-I, cardiac ATPase, heart mitochondrial, and lysosomal enzymes were assayed followed by histopathological screening. Rats treated with isoproterenol (85 mg/kg, s.c), administered twice at an interval of 24 h on 29th and 30th day showed a significant change in morphological and antioxidant parameters, biochemical markers, lipid profile, troponin-I, cardiac ATPase, heart mitochondrial, lysosomal enzymes activities and transcription factor (TNF-α/IL-6/NF-kB) expression. Pretreatment with d-limonene (200 and 400 mg/kg, p.o) for 28 days followed by ISO administration on 29^th and 30^th day significantly reversed the effects of isoproterenol-induced ischemic changes. Moreover, the biochemical results were validated by histopathological findings. The research indicates that d-limonene demonstrates cardioprotective potential against isoproterenol-induced myocardial infarction. This is attributed to its antioxidant properties, stabilization of myocardial membranes, improved scavenging of free radicals, and inhibition of membrane lipid peroxidation.