Evaluation of methanol extract of Gongronema latifolium leaves singly and in combination with glibenclamide for anti-hyperglycemic effects in alloxan-induced hyperglycemic rats

OBJECTIVE: This study evaluated the anti-hyperglycemic effect of the methanol extract of Gongronema latifolium leaves singly and in combination with an oral hypoglycemic agent; glibenclamide. MATERIALS AND METHODS: The plant material was extracted with methanol for 48 h using cold maceration and concentrated in vacuo in a rotary evaporator. The methanol extract of G. latifolium at doses of 200, 300, 400, 500, and 800 mg/kg were studied for anti-hyperglycemic effect in alloxan-induced hyperglycemic rats. More so, the extract at doses of 400 mg/kg + 5 mg/kg glibenclamide and 500 mg/kg + 5 mg/kg glibenclamide were studied for possible additive effects. RESULTS: The 300 mg/kg of the extract decreased blood glucose at 1 h post-treatment though not significantly (P > 0.05) compared with 5 ml/kg distilled water, but failed to lower the blood glucose at 3 and 6 h post-treatment. The 400 and 500 mg/kg decreased the blood glucose level from 1 to 6 h post-treatment. However, the decrease in blood glucose was only significant (P < 0.05) at 6 h post-treatment. The two combination protocol of the extract significantly (P < 0.05) decreased the blood glucose from 1 to 6 h post-treatment compared with 5 ml/kg distilled water. However, there was no significant (P > 0.05) difference between the effects of the combination protocol and glibenclamide 5 mg/kg alone though the effects of the combination protocol were better than that of glibenclmide 5 mg/kg alone. CONCLUSION: Our studies suggest that there is treatment benefit of combining extract of G. latifolium leaves and glibenclamide over G. latifolium or glibenclamide alone.