Authors are with CNRS, Cent Marseille, iSm2, Marseille, Aix Marseille Univ., Faculté des Sciences et Techniques de Saint Jérôme, Case 342, 13397, Marseille, France.
J Food Sci. 2018 Nov;83(11):2858-2865. doi: 10.1111/1750-3841.14353. Epub 2018 Oct 5.
Many studies have shown that flavan-3-ols inhibit mammalian alpha-amylases but the published IC and K values vary up to a thousand times. We therefore tested the effects of 6 pure flavan-3-ols-abundant in green tea-on the activity of pure porcine pancreatic alpha-amylase (PPA) under steady-state kinetic conditions. We used both amylose and maltopentaose as substrates, along with spectrophotometry and chromatography as analytical tools, respectively. A Docking approach was also used to probe the interaction between PPA and each flavan-3-ol. The results showed that the 6 flavan-3-ols inhibit amylose hydrolysis with K comprised between 7 and 34 μM, according to a mixed inhibition profile for gallocatechin gallate, and a competitive inhibition profile for the 5 other flavanols. Only the galloyl-containing flavan-3-ols inhibited the maltopentaose hydrolysis with a K of about 30 μM according to a noncompetitive profile. We conclude that dietary flavan-3-ols could inhibit starch digestion nonnegligibly. The results of the docking trials were concordant with the kinetic data and have noticeably revealed that the cis-flavan-3-ols epigallocatechin gallate and epicatechin gallate bind similarly to PPA, involving π-stacking with Trp59.
许多研究表明，黄烷-3-醇能够抑制哺乳动物的α-淀粉酶，但已发表的 IC 和 K 值差异可达千倍。因此，我们在稳态动力学条件下测试了 6 种在绿茶中含量丰富的纯黄烷-3-醇对纯猪胰腺α-淀粉酶（PPA）活性的影响。我们分别使用直链淀粉和麦芽五糖作为底物，同时使用分光光度法和色谱法作为分析工具。还采用对接方法来探测 PPA 和每种黄烷-3-醇之间的相互作用。结果表明，根据没食子酸酯对儿茶素没食子酸酯的混合抑制模式和其余 5 种黄烷醇的竞争性抑制模式，6 种黄烷-3-醇均抑制直链淀粉水解，K 值介于 7 至 34 μM 之间。只有含有没食子酰基的黄烷-3-醇根据非竞争性模式抑制麦芽五糖水解，K 值约为 30 μM。我们得出结论，饮食中的黄烷-3-醇可能会不可忽视地抑制淀粉消化。对接试验的结果与动力学数据一致，并明显表明顺式黄烷-3-醇表没食子儿茶素没食子酸酯和表儿茶素没食子酸酯与 PPA 结合方式相似，涉及与色氨酸 59 的π-堆积。
