Abstract
The effect of aqueous extracts of Syzygium cumini Linn., Gymnema sylvestre (Retz.) Schult., and Portulaca olearacea Linn. were investigated in fasting normal and streptozotocin (STZ)-induced diabetic rats. The effects of extracts on oral glucose tolerance in normal fasting rats were also studied. The aqueous extracts of S. cumini (200 mg/kg) and G. sylvestre (200 mg/kg) decreased the blood glucose in normal rats significantly at 2 and 4 h of extract administration (p < 0.05, p < 0.01). The S. cumini and G. sylvestre extracts decreased the increase of glucose levels significantly (p < 0.05) at 90 and 180 min after the glucose load in glucose tolerance test. In STZ diabetic animals, the aqueous extracts of S. cumini and G. sylvestre decreased the blood glucose significantly (p < 0.05) at 4 h. The aqueous extract of P. olearacea did not show any hypoglycemic activity.