Methanolic Leaf Extract of Parkia biglobosa Protects against Doxorubicin-induced Cardiotoxicity in rats

Parkia biglobosa aqueous-methanolic leaf extract, PBE (DER-10:1) was investigated for its effects on doxorubicin-induced cardiotoxicity, phytochemical constituents and in vitro antioxidant activity. Adult albino (200 – 220 g) rats were divided into seven groups (n = 6). The control and the doxorubicin-challenged, untreated groups received distilled water orally for 14 consecutive days while on the 13th day, the latter received single dose of doxorubicin (15 mg/kg i.p). The pretreated groups received ramipril (10 mg/kg b.w) or PBE (25 mg/kg, 50 mg/kg, 75 mg/kg and 200 mg/kg b.w) by gavage throughout and later were given doxorubicin (15 mg/kg i.p) on the 13^th day. Animals were sacrificed 20 hours after the last administration, the heart homogenate and serum were analysed for glutathione (GSH), superoxide dismutase (SOD), malondialdehyde (MDA), glutathione-s-transferase (GST), glutathione peroxidase (GPX), catalase (CAT), creatine kinase MB (CK-MB), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), cholesterol, high density lipoprotein (HDL), low density lipoprotein (LDL), and triglycerides (Trig). Results revealed the presence of saponins, tannins, cardiac glycosides, total flavonoid (256.86 mg Quercetin equivalent) and total phenol (144.18 mg gallic acid equivalent), significant reduction in the iron sulphate induced formation of MDA. Doxorubicin caused significant elevations (P < 0.05) of cardiac MDA, serum CK-MB, LDH, AST, Trig and LDL while causing significant reduction in the levels/or activities of cardiac GSH, GPX, GST, SOD and serum HDL. Pretreatment with PBE reversed these parameters to near normal levels. The protection offered compared well with that of ramipril. The results of this study reveal that PBE can protect against doxorubicin-induced toxicity and that the protection might be via antioxidative and antihyperlipidemic mechanisms

Key words: Parkia biglobosa (Fabaceae); cardiotoxicity; doxorubicin; antioxidative; antihyperlipidemic