构建电子转移通道阻抑法筛选车前子中黄嘌呤氧化酶抑制剂成分

目的：构建黄嘌呤氧化酶（XOD）电子转移通道阻抑方法筛选车前子中XOD抑制剂成分。方法：将双壁碳纳米管（DWNTS）固定于玻碳电极表面，并在其上修饰XOD，构建XOD催化反应电子转移通道。应用循环伏安法监测通道中的电子转移信号，当抑制剂成分存在阻止XOD催化黄嘌呤（XAN）反应时，通道电子转移信号下降，藉此筛选XOD抑制剂。结果：循环伏安法可灵敏监测XOD催化反应通道中电子转移阻抑信号，利用该法对车前子中的4个代表性单体成分进行筛选，共筛选出2个XOD抑制剂，分别为毛蕊花糖苷（IC₅₀为8.4 μg·mL^-1）、乙基己基-苯羧酸酯（IC₅₀为75.0 μg·mL^-1），其中乙基己基-苯羧酸酯为新筛选出的XOD抑制剂。结论：电子转移通道阻抑筛选方法简单快捷，灵敏度与选择性高，筛选化合物用量低，在天然产物XOD抑制剂的筛选中具有很好的应用前景。

Objective: To develop an electron transfer channel blocking method for screening of xanthine oxidase inhibitors from Plantaga asiatica L. Methods: DWNTS was firstly fixed on the surface of glass carbon electrode, on which XOD was modified, and the electron transfer for XOD catalytic reaction could be established. Doublewall carbon nanotubes were fixed on the surface of glass carbon electrode, on which xanthine oxidase is then modified, so as to develop the electron transfer channel for the catalysis reaction of XOD. The inhibitor activity of the compounds could be evaluated by the signal of electron transfer using cyclic voltammetry since the response signal would be greatly decreased by xanthine oxidase inhibitors. Results: Two compounds of acteoside and bisethythexyl-benzene-dicarboxylate isolated from P. asiatica L. were successfully identified as xanthine oxidase inhibitors, with IC₅₀ of 8.4 μg·mL^-1 and 75.0 μg·mL^-1 respectively, and bis-ethythexyl-benzene-dicarboxylate was for the first time screened as a xanthine oxidase inhibitor. Conclusion: The method is selective, sensitive, rapid, and convenient. It is hoped to be one of the most promising methods in the field of xanthine oxidase inhibitors research.