Cardioprotective Activities of Pterocarpus mildbraedii Leaves on Isoproterenol-induced Myocardial Infarction in Rats
Adeniyi Oluwadare Fajobi, B. O. Emma- Okon, O. O. Oyedapo, Christianah Dare, Akintunde Oluseto Akinlalu, Ige Joseph Komolafe, Mayowa Ogunsusi
Abstract
The study evaluated the effects of Pterocarpus mildbraedii leaf extracts on myocardial infarction induced by isoproterenol (ISO) in Wistar albino rats with a view to ascertain the value of its use in the management of heart-related diseases. Fresh plant leaves were collected, identified, extracted, fractionated and the aqueous layer partitioned with ethyl acetate. GC-MS was carried out on the ethyl acetate fraction (EAF) and unknown compounds were identified by comparing measured mass spectral data with those in NIST 14 Mass Spectral Library. Twenty-five adult rats were divided into five groups of 5 rats each. Groups I &II were the control groups. Rats in groups III-V were pretreated with 50 mg/kg and 100 mg/kg of EAF and 1.8 mg/kg of propranolol respectively for 21 days. Myocardial infarction was then induced in all the rats (except those in Group I) with the intraperitoneal injection of ISO (85 mg/kg) for 2 days. Afterwards, the rats were sacrificed and blood samples, heart homogenate and samples for histological studies were aseptically collected. Activities of cardiac biomarkers, lipid profile, enzymatic and non-enzymatic antioxidants were evaluated using standard methods. GC-MS analysis showed that the most abundant components of the plant are propionic acid, 2,3-dimethylphenyl ester, catechol, octyl-β-D-glucopyranoside, phenol and n-Hexadecanoic acid. Administration of ISO caused significant elevation of the activities of cardiac biomarkers (troponin-T concentrations, creatine kinase-MB and lactate dehydrogenase) while rats pretreated with EAF had significantly lower levels of the biomarkers. Moreover, alterations in lipid profile, enzymatic and non-enzymatic antioxidants brought about by the administration of ISO were ameliorated. Histological examinations revealed lesser degree of myocardial injury in pre-treated rats.