Effects of methanolic leaf extract of Kigelia africana on hemodynamic parameters and redox status of normotensive wistar rats

Abstract

Kigelia Africana has a rich history of ethnobotanical usage in the treatment of a wide range of illnesses andcomplications like hypertension, cancer and microbial infections in south western Nigeria. The present work sought to investigate the effects of methanolic leaf extract of Kigelia Africana on the blood pressure and biochemical indices of normotensive albino rats. Twenty five male albino Wistar rats, weighing between 180-200g, and divided into five groups (I-V) of five animals each were used for the experiment. GroupsII – V were administered 1mg/kg b.w ramipril, 25-, 50- and 100mg/kg b.wKigelia Africana respectively by oral gavage for 14 consecutive days. Group I received vehicle (1 mg/kg distilled water) only throughout the duration of the experiment and served as control. Twenty-four hours after the last administration, the blood pressure was determined before sacrificing the animals following anesthesia. The activities of serum biomarkers (aspartate aminotransferase AST, total protein TP, alanine aminotransferase ALT, alkaline phosphatase ALP), serum lipid profile; (cholesterol TC, low/very low density lipoprotein LDL-c/VLDL-c, high density lipoprotein HDL and triglyceride TG) and cardiac antioxidant indices (catalase CAT, superoxide dismutase SOD and glutathione GSH) were determined. Administration of ramipril (1mg/kg b.w) and all dosages of Kigelia africana (25, 50 and 100mg/kg b.w) caused significant (P<0.05) decrease in the blood pressure of the animals when compared to the control. The values obtained further showed that ramipril and the extract (at all dosages) caused significant reduction in TC, TG, LDL-c and VLDL-c and coronary risk index, CRI while there was significant increase in the level of HDL when compared to the control. All dosages of Kigelia africana extract resulted in significant (P<0.05) decrease in serum activities of AST, ALT and ALP when compared with the control. The significant (P<0.05) increases in cardiac catalase activity and GSH concentration recorded in rats treated with Kigelia africana (25, 50 and 100mg/kg b.w.) were comparable with those administered the reference drug, ramipril (1 mg/kg). Cardiac SOD activity was however decreased in rats administered extract (25, 50 or 100 mg/kg b.wt) and ramipril (1mg/kg bw). The results suggest the hypolipidemic, hypotensive and antioxidant properties and of methanolic extract of Kigelia africana leaf and lend support to the ethnobotanical usage of the leaf in the treatment of hypertension.