Antihyperglycaemic and antihyperlipidaemic effects of aqueous ethanol extract of Tapinanthus globiferus leaves and Treculia africana root bark and their mixture on alloxan diabetic rats

Abstract

The plants Treculia africana and Tapinanthus globiferus are ethnobotanically used in the treatment of various diseases including diabetes and heart diseases. Diabetes mellitus is a disease characterized by hyperglycemia and hyperlipidemia which leads to an increased risk of atherosclerosis and other cardiovascular diseases. The effects of aqueous ethanol (96%) extracts of T. africana leaves and Tapinanthus globiferus plants and their mixture, in an equal proportion, were evaluated on postprandial glycemic status. Four groups of normal rats were treated with the extracts at a dose 250mg/kg each, their mixture (1:1), at a dose of 500 mg/kg body weight, 0.5ml of acacia (2%w/v) and then charged with glucose (40%) at a dose of 1 ml/100 g body weight. Plasma sugar contents were analyzed from the blood collected from the tail vein at 30, 60, 90 and 120 min intervals. Also glycemic status and serum lipid profiles of normal and Alloxan-induced diabetic rats were evaluated. Five groups of alloxan-induced diabetic (150 mg/kg ip) rats were treated with the extracts and the (1:1) mixture at a dose of 500 mg/kg, respectively for 21 days. Significant reduction (p≤0.05) in both postprandial blood glucose but not in alloxan-induced diabetes blood glucose levels, triglyceride levels, low density lipoprotein (LDL) level, and increase in high density lipoprotein (HDL) level were observed in the mixture. This scientific finding does not support the basis for the herbal use of mixture of T. africana and Tapinanthus globiferus in the management of diabetes and heart diseases.