Antihyperglycaemic and Hypolipidemic Studies of Three Medicinal Plants on Alloxan-induced Diabetic Rats

Ethanolic extracts of Canarium schweinfurthii stem bark and Senna alata leaf, and aqueous extract of unripe Carica papaya fruit, at two different doses (150, 400 mg/kg), were evaluated for antihyperglycaemic and hypolipidemic effects on alloxan-induced diabetic rats following daily oral administration for 28 days. While antihyperglycaemic effect was lacking in Senna alata, it was persistent (P<0.05) in Canarium schweinfurthii and Carica papaya. The activity was comparable to that of chlorpropamide at 100 mg/kg. All three extracts significantly (P<0.05) attenuated all lipid parameters, except HDL-cholesterol which increased significantly in rats treated with Senna alata and Carica papaya extracts without any appreciable weight gain. Hypolipidemic effect is reported for the first time for Canarium schweinfurthii stem bark. Signs of toxicity included renotoxicity by Canarium schweinfurthii and Carica papaya extracts which was typified by marked vascular congestion with extensive areas of intraparenchyma and glomerular haemorrhage. Further congestion of lungs with extensive harmorrhage in Carica papayatreated rats and intraparenchyma haemorrhage of the heart of Senna alata-treated animals were also evident. This study though supports folkloric usage of the three plants in the traditional management of diabetes and related conditions may not be safe for long term usage until evaluated for further toxicity studies.