Effect of the methanolic extract of Brachylaena discolor in a streptozotocin-induced diabetic rat model

Traditionally, leaf infusions of Brachylaena discolor are used for the treatment of diabetes and renal conditions. Therefore, the aim of this study was to evaluate the effect of a methanolic leaf extract of B. discolor in a streptozotocin (STZ)-induced diabetic rat model. Diabetes was induced in Wistar rats by an intraperitoneal injection of STZ; blood glucose levels greater than 20 mmol/L measured after 7 days confirmed a stable diabetic mellitus state. Two doses of the test extract (50 and 150 mg/ml) were administered daily via oral dosing to both STZ-induced and control rats. Blood was obtained from the tail vein and used to measure the effects of the extract on the biochemical profile of the rats over 28 days. The methanolic leaf extract of B. discolor at both doses (50 and 150 mg/ml) caused a significant reduction in the blood glucose levels at 7, 14, 21 and 28 days in STZ-induced diabetic rats when compared with the normal rats (negative control). Significant differences were also observed in alkaline phosphatase, creatinine, total bilirubin and body weights of extract treated diabetic rats when compared with untreated diabetic rats, normal rats and metformin treated rats. Findings suggest that B. discolor exhibits significant anti-hyperglycaemic activity in STZ-induced diabetic rats.   Key words: Diabetes, streptozotocin, Brachylaena discolor, Wistar rats.