目的 研究蒲公英水提取物降低鏈脲佐菌素（STZ）致糖尿病大鼠餐后血糖水平的作用及其機制。方法 考察蒲公英水提取物 400、200、100 mg/kg對STZ致糖尿病模型大鼠餐后血糖水平的影響，并采用ELISA法檢測各組大鼠血清胰島素水平；正糖鉗實驗考察蒲公英水提取物對正常大鼠胰島素敏感性的影響，檢測葡萄糖輸注率（GIR）；以pNPG為底物，測定蒲公英水提取物400 mg/kg體外對α-糖苷酶活性的影響；采用Caco-2細(xì)胞單層模擬的小腸上皮模型，評價蒲公英水提取物200、100 mg/L對小腸麥芽糖水解和葡萄糖吸收能力的影響。結(jié)果 蒲公英水提取物400、200、100 mg/kg給藥7 d，可顯著降低正常大鼠及STZ致糖尿病大鼠餐后血糖水平，但對血清胰島素水平、GIR均無影響。蒲公英水提取物對α-糖苷酶活性具有抑制作用，但半數(shù)抑制濃度（IC₅₀）高于陽性藥阿卡波糖；蒲公英水提取物 200 mg/L可同時抑制Caco-2細(xì)胞單層對麥芽糖的水解和對葡萄糖的轉(zhuǎn)運。結(jié)論 蒲公英水提取物具有降低餐后血糖的作用，其作用機制與抑制小腸對麥芽糖的水解和對葡萄糖的吸收有關(guān)。

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.