Abstract

Decoctions of Persea americana Mill (Lauraceae) leaves are employed to manage diabetes mellitus among the Ibo communities of Eastern Nigeria. In this study, we studied the ameliorative effects of the aqueous extract of P. americana leaves (AEPAL) on alloxan-induced hyperglycaemia and hyperlipidaemia in Wistar rats. The oral median lethal dose (LD₅₀) of AEPAL was determined in rats. The effects of extract on blood glucose and lipids levels; and biochemical parameters were evaluated. The effects of AEPAL on relative organs weights, body weight changes as well as food and water consumption were monitored for 28 days in alloxan-induced hyperglycaemic rats and histopathological changes of the pancreas examined. The estimated oral LD₅₀ of AEPAL was greater than 5000 mg kg^–1. AEPAL (125–500 mg kg^–1) significantly reduced the fasting blood glucose levels and hyperlipidaemia in the alloxan-induced hyperglycaemic rats. The extract significantly reversed the decreased body weight, increased food and water intake; and attenuated elevated levels of aspartate transaminase (AST), urea, total protein (TP), albumin (ALB), alanine transaminase (ALT) and alkaline phosphatase (ALP) in alloxan-induced hyperglycaemic rat. Histological examination of the pancreas showed regeneration of the β–cells of the Islet of Langerhans in the extract treated alloxan-induced hyperglycaemic rat. Our findings revealed that AEPAL contains biologically active components with potential hypoglycaemic activity, thus supporting its further development for the management of diabetic mellitus.

Key words: Persea americana, acute toxicity, antidiabetic, β–cells, metformin.