Antihyperglycemic activity of Zanthoxylum chalybeum stem bark extract in diabetic rats

Zanthoxylum chalybeum Engl. (Rutaceae) stem bark is used by communities in Africa and Asia to manage diabetes mellitus. This study determined the anti-hyperglycemic effect of Z. chalybeum aqueous stem bark extract in streptozotocin-induced diabetic rat. The plant was obtained from Machakos County, Kenya and a stem bark extract prepared. Rats were divided into experimental (n=5), negative control (n=5) and positive control groups (n=5). Diabetes was induced in each rat in experimental groups by a single dose intraperitoneal injection of Streptozotocin at 45mg/kg body weight. The plant extract was administered orally to the experimental rats at dosages of 10, 100 and 1000mg/kg body weight for 14 days. The negative control group was left untreated while the positive control group was treated orally with glibenclamide (10mg/kg body weight). The effect of the extract on blood glucose, body weight, food and water intake and oral glucose tolerance were determined in all rats in the experimental and control groups. The aqueous stem bark extract exhibited significant antidiabetic activity compared to the untreated diabetic controls (P<0.05). Additionally, there was no significant difference between the extract fed diabetic rats and the normal controls. Furthermore, extract treated diabetic animals recorded a comparatively decreased weight loss which was dose dependent. These results suggest that the aqueous stem bark extract of Z. chalybeum possesses significant antihyperglycemic activity. This study thus corroborates the traditional use of the plant for the management of diabetes. However, further studies are required to identify the active ingredient(s) and determine the mode of action.