We optimized the assays used to measure inhibition of rat and human α-glucosidases (sucrase and maltase activities), intestinal enzymes which catalyze the final steps of carbohydrate digestion. Cell-free extracts from fully differentiated intestinal Caco-2/TC7 monolayers were shown to be a suitable source of sucrase–isomaltase, with the same sequence as human small intestine, and were compared to a rat intestinal extract. The kinetic conditions of the assay were optimized, including comparison of enzymatic and chromatographic methods to detect the monosaccharide products. Human sucrase activity was more susceptible than the rat enzyme to inhibition by acarbose (IC₅₀ (concentration required for 50% inhibition) = 2.5 ± 0.5 and 12.3 ± 0.6 μM, respectively), by a polyphenol-rich green tea extract, and by pure (−)-epigallocatechin gallate (EGCG) (IC₅₀ = 657 ± 150 and 950 ± 86 μM respectively). In contrast, the reverse was observed when assessing maltase activity (e.g., EGCG: IC₅₀ = 677 ± 241 and 14.0 ± 2.0 μM for human and rat maltase, respectively). 5-Caffeoylquinic acid did not significantly inhibit maltase and was only a very weak inhibitor of sucrase. The data show that for sucrase and maltase activities, inhibition patterns of rat and human enzymes are generally qualitatively similar but can be quantitatively different.

中文翻译：

---

抑制人和大鼠蔗糖酶和马耳他糖酶活性以评估抗血糖潜力：使用阿卡波糖和多酚的测定方法的优化

我们优化了用于测量对大鼠和人α-葡萄糖苷酶（蔗糖酶和麦芽糖酶活性）的抑制作用的检测方法，这些酶催化碳水化合物消化的最终步骤。来自完全分化的肠Caco-2 / TC7单层的无细胞提取物被证明是蔗糖酶-异麦芽糖酶的合适来源，其序列与人的小肠相同，并与大鼠肠提取物进行了比较。优化了测定的动力学条件，包括比较酶法和色谱法以检测单糖产物。人蔗糖酶活性比大鼠酶更容易受到阿卡波糖的抑制（IC ₅₀（抑制50％所需的浓度）分别为2.5±0.5和12.3±0.6μM），富含多酚的绿茶提取物和纯的（-）-表没食子儿茶素没食子酸酯（EGCG）（IC ₅₀ = 657±150和分别为950±86μM）。相反，在评估麦芽糖酶活性时观察到相反的情况（例如，人和大鼠麦芽糖酶的EGCG：IC ₅₀ = 677±241和14.0±2.0μM）。5-咖啡酰奎宁酸没有显着抑制麦芽糖酶，只是蔗糖酶的一种非常弱的抑制剂。数据表明，对于蔗糖酶和麦芽糖酶活性，大鼠和人类酶的抑制模式通常在质量上相似，但在数量上可以不同。