Hypoglycemic effects of aqueous extract from Taraxaci Herba on diabetic rats induced by Streptozotocin and its mechanism / 中草药

ABSTRACT

Objective: To evaluate the hypoglycemic effect of aqueous extract from Taraxaci Herba (AETH) on postprandial blood glucose (PBG) in diabetic rats induced by Streptozotocin (STZ) and to explore the mechanism. Methods: The PBG within 120 min was measured after 7 d ig administration of AETH (400, 200, and 100 mg/kg) in normal rats and diabetic model rats induced by STZ, and ELISA was performed to detect the serum insulin of rats in each group. The euglycemic clamp assay was performed to investigate the effect of AETH (400 mg/kg) on the insulin sensitivity in normal rats, and the glucose infusion rate (GIR) was detected. The 50% inhibiting concentration (IC50) against α-glucosidase was measured in vitro, using pNPG as substrate. Caco-2 cells were preincubated for 72 h with AETH (200 and 100 mg/L), and then the capacities of Caco-2 monolayer on maltose hydrolysis and glucose absorption were measured. Results: The 7 d ig administration of AETH decreased the PBG significantly in diabetic rats induced by STZ, but had no effect on serum insulin level and GIR. AETH inhibited α-glucosidase in vitro, and the IC50 was higher than that of acarbose. AETH (200 mg/L) inhibited the capacities of Caco-2 monolayer on both maltose hydrolysis and glucose absorption. Conclusion: AETH has the hypoglycemic effect on PBG in diabetic rats, and the mechanism is related to the inhibition of maltose hydrolysis and glucose absorption in small bowel.