目的 研究葛根素通過抑制鈉-葡萄糖協(xié)同轉(zhuǎn)運(yùn)蛋白2（SGLT2）發(fā)揮促尿糖、降血糖作用。方法 同源模建獲得SGLT2蛋白虛擬結(jié)構(gòu)，以達(dá)格列凈為陽性藥，與葛根素進(jìn)行分子對接，考察其分子結(jié)合強(qiáng)弱；采用能穩(wěn)定表達(dá)人SGLT2（hSGLT2）蛋白的中國倉鼠卵巢（CHO）細(xì)胞、以^14C-甲基葡萄糖苷（[^14C]-AMG）為底物，評價葛根素體外抑制SGLT2的活性；以達(dá)格列凈為陽性藥，采用大鼠體內(nèi)口服糖耐量試驗（OGTT）和尿排泄糖試驗（UGE）觀察葛根素直接降血糖和促尿糖活性。結(jié)果 分子對接得分顯示，葛根素是SGLT2的底物，總體作用強(qiáng)度不及達(dá)格列凈；體外實驗顯示，葛根素可較強(qiáng)抑制hSGLT2，最大效應(yīng)為84%左右，半數(shù)抑制濃度（IC₅₀）為0.40 μmol/L；OGTT結(jié)果顯示，葛根素10、30、60和120 mg/kg劑量的抑糖率分別為5.1%、6.5%、16%和22%，呈劑量相關(guān)性；在UGE實驗中，隨著葛根素劑量的增大，尿糖量增加，與模型組比較，30、60和120 mg/kg劑量組差異顯著（P<0.05、0.01）。結(jié)論 葛根素具有抑制hSGLT2、促尿糖降低血糖的藥理活性，有可能作為一類新型結(jié)構(gòu)的SGLT2抑制劑的先導(dǎo)化合物。

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.

陜西省教育廳專項科研（15JK1203）；陜西省高校科協(xié)青年人才托舉計劃資助（20160227）