目的 研究荭草素和异荭草素降血糖的靶点及其体外活性。方法 从蛋白质数据库（www.rcsb.org）获取糖尿病相关靶点蛋白结构，利用虚拟分子对接打分评价荭草素和异荭草素与糖尿病相关靶点的结合强弱；基于分子对接的结果，采用荧光标记的1-脱氧葡萄糖（1-NBDG）、4-硝基苯基-α-D-葡萄糖苷PNDG（PNPG）、对硝基苯酚磷酸酯（pNPP）作为底物对荭草素和异荭草素进行体外抑制α-葡萄糖糖苷酶、钠–葡萄糖协同转运蛋白2（SGLT2）和蛋白酪氨酸磷酸酶1B（PTP1B）活性评价。结果 荭草素与α-葡萄糖苷酶、SGLT2、和PTP1B的分子对接得分分别为-5.67、-9.32、-4.75，异荭草素与α-葡萄糖苷酶、SGLT2和PTP1B的分子对接得分分别为-5.34、-8.63、-4.93，而阳性对照药与靶标的分子对接打分依次是-5.58、-9.79、-9.28。体外实验显示，荭草素对α-葡萄糖苷酶、SGLT2、PTP1B的抑制率依次是（16.7±5.8）%、（15.4±1.2）%、（3.0±0.5）%，异荭草素对α-葡萄糖苷酶、SGLT2、PTP1B的抑制率依次是（11.8±3.8）%、（9.4±1.1）%、（-3.8±0.6）%，而阳性对照对α-葡萄糖苷酶、SGLT2、PTP1B的抑制率依次为（63.7±5.8）%、（92.7±8.8）%、（73.4±8.3）%。结论 荭草素和异荭草素对SGLT2和α-葡萄糖苷酶具有一定的抑制活性，对PTP1B几乎没有抑制作用，且荭草素的体外活性略强于异荭草素，荭草素有可能作为一类具有双靶点作用的降血糖药物的先导化合物。

Objective To study the hypoglycemic target of orientin and isoorientin and their activities in vitro. Methods The structure of diabetes-related target proteins was obtained from the www.rcsb.org database, and the binding of orientin and isorientin to diabetes-related target proteins was evaluated by virtual molecular docking score, the inhibitory effects of orientin and isoorientin on α-glucosidase, SGLT2, and PTP1B in vitro were evaluated by using 1-NBDG, PNDG and PNPP as substrates. Results The molecular docking scores of orientin with α-glucosidase, SGLT2, and PTP1B were −5.67, −9.32, and −4.75, respectively. Molecular docking scores of isoorientin with α-glucosidase, SGLT2, and PTP1B were −5.34, −8.63, and −4.93, respectively, while the molecular docking scores of positive control drug and target were −5.58, −9.79 and −9.28, respectively. The inhibition rates of orientin on α-glucosidase, SGLT2, and PTP1B were (16.7 ± 5.8) %, (15.4 ± 1.2) %, and (3.0 ± 0.5) %, respectively. The inhibitory rates of isoorientin on α-glucosidase, SGLT2, and PTP1B were (11.8 ± 3.8) %, (9.4 ± 1.1) %, and (−3.8± 0.6) %, respectively. The inhibition rates of α-glucosidase, SGLT2, and PTP1B in positive control were (63.7± 5.8) %, (92.7 ± 8.8) % ,and (73.4 ± 8.3) %, respectively.Conclusion Orientin and isorientin showed certain inhibitory activities on SGLT2 and α-glucosidase, and had little inhibitory effect on PTP1B, and oriorientin was slightly stronger than isorientin in vitro, orientin may be a potential lead compound for a class of hypoglycemic agents with dual-target effects.

R285

陕西省自然科学基础研究计划（2019JQ-401）；陕西中医药大学校级科研课题（2020GP32）