葛根素抑制钠-葡萄糖协同转运蛋白2活性发挥促尿糖作用研究

目的 研究葛根素通过抑制钠-葡萄糖协同转运蛋白2（SGLT2）发挥促尿糖、降血糖作用。方法 同源模建获得SGLT2蛋白虚拟结构，以达格列净为阳性药，与葛根素进行分子对接，考察其分子结合强弱；采用能稳定表达人SGLT2（hSGLT2）蛋白的中国仓鼠卵巢（CHO）细胞、以^14C-甲基葡萄糖苷（^14C]-AMG）为底物，评价葛根素体外抑制SGLT2的活性；以达格列净为阳性药，采用大鼠体内口服糖耐量试验（OGTT）和尿排泄糖试验（UGE）观察葛根素直接降血糖和促尿糖活性。结果 分子对接得分显示，葛根素是SGLT2的底物，总体作用强度不及达格列净；体外实验显示，葛根素可较强抑制hSGLT2，最大效应为84%左右，半数抑制浓度（IC₅₀）为0.40 μmol/L；OGTT结果显示，葛根素10、30、60和120 mg/kg剂量的抑糖率分别为5.1%、6.5%、16%和22%，呈剂量相关性；在UGE实验中，随着葛根素剂量的增大，尿糖量增加，与模型组比较，30、60和120 mg/kg剂量组差异显著（P<0.05、0.01）。结论 葛根素具有抑制hSGLT2、促尿糖降低血糖的药理活性，有可能作为一类新型结构的SGLT2抑制剂的先导化合物。

Inhibition of puerarin on sodium-dependent glucose cotransporters 2 to promote urinary glucose excretion

Objective To study that puerarin can prevent the renal glucose reabsorbtion process and promote urinary glucose excretion by inhibiting sodium-dependent glucose cotransporters 2 (SGLT2) to reduce plasma glucose in diabetes rats. Methods Molecular docking was carried out on puerarin and the obtained SGLT2 complexes through homology modeling method with dapagliflozin as positive control. Chinese hamster ovary (CHO) cells stably expressing human SGLT2 and^14C]-Methyl- D-glucopyranoside (^14C]-AMG) as the substrate were used in vitro for the transport assays and IC₅₀ for SGLT2. The antihyperglycemic activity of puerarin was operated by oral glucose tolerance test (OGTT) and urinary glucose excretion (UGE) test in rats. Results Puerarin was identified as the substrate of SGLT2 through molecular docking, but the overall effect was not as strong asdapagliflozin. In vitro experiments showed that puerarin can strongly inhibit hSGLT2, the maximum effect was about 84% with the half inhibitory concentration (IC₅₀) of 0.40 mol/L. OGTT results showed that glucose inhibition rates of puerarin 10, 30, 60 and 120 mg/kg doses were 5.1%, 6.5%, 16%, and 22% respectively, in a dose-dependent manner. In the UGE experiment, the urine sugar increased with the increase of puerarin dose. Compared with model group, the 30, 60, and 120 mg/kg dose groups had significant difference (P<0.05 and 0.01). Conclusion Puerarin exhibited antiglycemic activity through inhibiting SGLT2 and was considered to be a new lead compound of SGLT2 inhibitors.