An online method based on CE was established to screen α-glucosidase inhibitors from traditional Tibetan medicine extracts. First, the inner wall at the inlet of capillary column was simply and effectively functionalized by dopamine-polyethyleneimine co-deposition method, which combines the adhesion property of dopamine and easy cationization of polyethyleneimine. Then α-glucosidase was rapidly immobilized on the inner wall of the capillary column by electrostatic adsorption. The inter- and intraday repeatability of the peak area of the enzymatic reaction product (p-nitrophenol) in a capillary was evaluated, and RSD% (n = 3) was 0.94% and 1.09%, respectively. Good batch-to-batch reproducibility of the peak area between different capillaries (RSD = 2.1%, n = 5) shows that the preparation method has good reproducibility. The Michaelis–Menten constant of the immobilized α-glucosidase was measured to be 1.18 mM, and the capillary column enzyme reactor retained 85.9% of initial activity after 30 cycles. Finally, it was applied to the screening of enzyme inhibitors in 20 traditional Tibetan medicine extracts. Sixteen medicines with inhibitory activity were screened out, and Rheum australe had the strongest inhibitory effect with an inhibitory rate of 83.3 ± 0.4%. These results showed that this method is effective to find potential enzyme inhibitors.

中文翻译：

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多巴胺-聚乙烯亚胺共沉积用于固定α-葡萄糖苷酶的毛细管及其在酶抑制剂筛选中的应用

建立了基于CE的在线方法从藏药提取物中筛选α-葡萄糖苷酶抑制剂。首先，采用多巴胺-聚乙烯亚胺共沉积法对毛细管柱入口内壁进行简单有效的功能化，该方法结合了多巴胺的粘附性和聚乙烯亚胺的易阳离子化特性。然后通过静电吸附将α-葡萄糖苷酶快速固定在毛细管柱的内壁上。对毛细管中酶促反应产物（对硝基苯酚）峰面积的日间和日内重复性进行了评估，RSD%（n = 3）分别为 0.94% 和 1.09%。不同毛细管之间峰面积的良好批次间重现性（RSD = 2.1%，n= 5) 表明该制备方法具有良好的重现性。经测量，固定化 α-葡萄糖苷酶的 Michaelis-Menten 常数为 1.18 mM，并且毛细管柱酶反应器在 30 个循环后保留了 85.9% 的初始活性。最后将其应用于20种藏药提取物中酶抑制剂的筛选。筛选出16种具有抑制活性的药物，以大黄的抑制作用最强，抑制率为83.3±0.4%。这些结果表明，该方法可有效地发现潜在的酶抑制剂。