Hypoglycaemic activity of ethyl acetate fraction of the leaf extract of Telfairia occidentalis.

The leaf of Telfairia occidentalis has been found to possess hypoglycemic or antihyperglycemic effect. The hypoglycemic principle of the leaf is yet to be isolated. The aim of this study is to evaluate the hypoglycemic activity of some fractions of ethanolic leaf extract of Telfairia occidentalis in rat as a step toward activity directed isolation of the hypoglycemic component. Ethanolic leaf extract was successively extracted with ethyl acetate, butanol and ethanol to obtain ethyl acetate, butanol and ethanol fractions (I-III). The residue was taken as fraction IV. 250 mg/kg of the various extracts were orally administered to normoglycaemic and alloxan-induced diabetic albino rats. Blood glucose concentration was evaluated at 0, 1, 2 and 4 hours after treatment with One Touch glucometer. None of the fractions reduced glucose concentration in the normoglycaemic rats, while only ethyl acetate fraction lowered glucose concentration significantly at 2 and 4 hours (49.7 and 39.0%) compared to control value of 74.9 and 69.7%, respectively, in the diabetic rats. The results showed that the hypoglycemic component of the ethanolic leaf extract of the plant is contained in the ethyl acetate fraction.

Screening of the seed of Picralima nitida for hypoglycaemic activity.

The seed extract of picralima nitida was screened for hypoglycaemic activity. The hypoglycaemic activity was evaluated in both normoglycemic and alloxan-induced diabetic rats, using glibenclamide as a reference drug. In both normoglycaemic and alloxan diabetic groups, 250 mg kg(-1) of the extract, 5 mg kg(-1) glibenclamide and a mixture of the extract (125 mg kg(-1)) and glibenclamide (2.5 mg kg(-1)) were administered orally, respectively. Blood glucose was measured with a glucometer at 0, 1, 2 and 4 h. In the sub acute group, the same doses as above were administered to diabetic rats once daily for 14 days and blood glucose was determined on days 1, 5, 10 and 15. The seed extract did not show any hypoglycaemic effect in both normoglycaemic and alloxan diabetic rats. Rather, the extract increased blood glucose concentration in the sub acute group on days 5, 10 and 15. These results indicate that, unlike the fruit pulp, the seed extract of Picralima nitida did not possess hypoglycaemic activity.