Hypoglycemic activity of the ethyl acetate extract from Smilax glabra Roxb in mice: Biochemical and histopathological studies

Objective(s): This research was carried out to investigate the hypoglycemic activity of the ethyl acetate (EtOAc) extract from the roots of Smilax glabra Roxb, which strongly exhibit inhibitory activity against alpha-glucosidase and a-amylase on in vivo type 2 diabetic model. Materials and Methods: Column chromatography combined with crystallization was used to isolate the active fraction and compounds. Chemical structures of the compounds were determined based on the analysis of the spectroscopic data and comparison with the literature data. The alpha-glucosidase inhibitory activity (AGI) and the alpha-amylase inhibitory activity (AAI) were determined quantitatively spectrophotometrically using p-nitrophenyl alpha-D-glucopyranoside and soluble starch as substrates, respectively. The hypoglycemic activity was examined by evaluating its effects on glucose and insulin levels, insulin resistance, and histopathology of the pancreatic islets and livers in diabetic induced mice administrated with nicotinamide-streptozotocin. Results: The EtOAc extract and the bioactive compounds astilbin and 5-0-caffeoylshikimic acid in the extract were isolated and confirmed in structures, AGI, and AAI. The treatment at the doses of 500 and 1000 mu g/kg of body weight reduced blood glucose levels down to the physiological level of the physical controls in the diabetic mice after two weeks (P