Concurrent Administration of the Methanol Leaf Extract of Leptadenia Hastata (Pers) Decne (Apocynaceae) With Metformin or Glibenclamide Influences Blood Glucose Handling in Normal Rats

Background: Leptadenia hastata (Pers) Decne (Apocynaceae) is a familiar medicinal plant utilized in northern Nigeria either singly or together with conventional drugs to treat diabetes mellitus. Objective: This study investigated the influence of concurrent administration of the methanol leaf extract of L. hastata with Metformin or Glibenclamide on blood glucose handling in normal male Wister rats. Methods: One hundred and twenty-eight normal rats were randomized into 16 groups of 8 rats each. The first group served as a vehicle administered control. Three groups were treated with three increasing doses of the extract using a semilogarithmic scale (50mg/kg, 150mg/kg and 500mg/kg respectively). Another three groups were treated with Glibenclamide at doses of 0.3mg/kg, 1mg/kg and 3mg/kg respectively. Another three groups were treated with metformin at doses of 30mg/kg, 100mg/kg, and 300mg/kg respectively. Another three groups were treated with metformin (100mg/kg) co-administered with the extract at 50mg/kg, metformin 100mg/kg and the extract at 150mg/kg, metformin 100mg/kg and the extract at 500mg/kg respectively. The last three groups received Glibenclamide at 1mg/kg co-administered with the methanol extract at 50mg/kg, Glibenclamide at 1mg/kg with the extract at 150mg/kg, and Glibenclamide 1mg/kg with the extract at 500mg/kg respectively. Oral glucose tolerance test (OGTT) was conducted following 8 hours of fasting. Results: The result revealed a significant reduction in the total area under the glucose tolerance curve when metformin was co-administered with the extract in normal rats. Conclusion: The findings suggest that the methanol leaf extract of L. hastata when co-administered with metformin caused an enhancement of the effect of metformin following OGTT in normal rats. Keywords: Blood glucose, extract, metformin, glibenclamide, glucose tolerance.