[Antidiabetic activity of the leaves of Vemonia colorata (Wilid.) Drake (Composees) in alloxan-induced diabetic rats].

Vemonia colorata is distributed through Africa (Benin, Cameroon, Senegal, Togo etc...). Its leaves are commonly used by african tradipractitioners for treating diabetes. However, the antidiabetic activity of the leaves of V. colorata had never been investigated in experimental conditions. The present study aimed to test the aqueous extract of the leaves of V. colorata for its effects in normoglycaemic and alloxan-induced diabetic rats in comparison to glibenclamide antidiabetic activity. Such glibenclamide, the aqueous extract of V. colorata (300 mg/kg, per os) induced a significant hypoglycaemic effect in normoglycaemic rats. The blood glucose varied from 0.77 +/- 0.01 to 0.58 +/- 0.01 g/l (p < 0.05, n = 5). It also reduced significantly the fasting glucose level of the hyperglycaemic rats induced with oral administration of glucose (4 g/kg). In alloxan-induced diabetic rats, glibenclamide (0.2 mg/kg, per os) lowered significantly the blood glucose from 2.40 +/- 0.30 to 0.70 +/- 0.40 g/l (p < 0.05, n = 5). As well as glibenclamide, the aqueous extract of V. colorata (300 mg/kg, per os) decreased the blood glucose in alloxanic rats from 2.80 +/- 0.10 to 1.00 +/- 0.20 g/l (p < 0.05, n = 5). The aqueous extract of the leaves of V. colorata possesses both hypoglycaemic and antidiabetic effect in normoglycaemic and alloxan-induced diabetic rats. This may indicate the ethnopharmacological basis of the use of V. colorata leaves in traditional medicine for treating diabetes.