Insulin sensitizing effect as possible mechanism of the antidiabetic properties of the methanol and the aqueous extracts from the trunk bark of Ceiba pentandra

The objective of this study was to determine the antidiabetic mechanism of the aqueous (AE) and methanol (ME) extracts from Ceiba pentandra. The Oral Glucose Tolerance Test was performed in normal rats pretreated with AE and ME at doses of 75 and 150 mg/kg. The effects of these extracts were further evaluated on hepatic glycogenolysis, gluconeogenesis, and glycogen synthesis using HepG2 cells in presence of insulin. The ability of the extracts to inhibit hemoglobin glycation was also determined. Results from OGTT show that AE and ME significantly reduced hyperglycemia in a dose-dependent manner. AE and ME significantly inhibited gluconeogenesis by 8.89% and 15.59% respectively. Only ME in presence of insulin, significantly increase glycogen synthesis (29.65%). AE and ME also significantly inhibited hemoglobin glycation by 11 and 16%. These results suggest that AE and ME antidiabetic effects may at least partially result from the inhibition of gluconeogenesis, promotion of glycogen synthesis and inhibition of hemoglobin glycation.