Department of Food Chemistry, Institute of Biochemistry and Technical Biochemistry , University of Stuttgart , Allmandring 5b , 70569 Stuttgart , Germany.
Institute of Organic Chemistry , University of Stuttgart , Pfaffenwaldring 55 , 70569 Stuttgart , Germany.
J Agric Food Chem. 2019 Oct 9;67(40):11108-11118. doi: 10.1021/acs.jafc.9b04798. Epub 2019 Sep 24.
A blood glucose level lowering effect is postulated for polyphenols (PPs), which is in part attributed to the inhibition of α-amylase. To estimate structure-effect relationships, chlorogenic acid (CA), phlorizin (PHL), epigallocatechin gallate (EGCG), epicatechin (EC), and malvidin-3-glucoside (Mlv-3-glc) were used as inhibitors in an enzyme assay, on the basis of the conversion of GalGCNP by α-amylase. The detection of CNP was performed by UV/vis spectroscopy. The data reveal that the inhibitor strength decreases as follows: EGCG > Mlv-3-glc > EC > PHL ∼ CA. Detection of the substrate conversion by isothermal titration calorimetry supports these results. All PPs showed mixed inhibition, except for CA and EGCG wherein the competitive proportion was predominant. Investigations by saturation transfer difference NMR revealed interaction of PPs with α-amylase prevalently based on interactions with the aromatic or conjugated system. A correlation between the extent of the conjugated system and the IC of the PP could be found.
人们推测多酚（PPs）具有降低血糖的作用，这在一定程度上归因于对α-淀粉酶的抑制。为了评估结构-效应关系，根据α-淀粉酶对GalGCNP 的转化，使用绿原酸（CA）、根皮苷（PHL）、表没食子儿茶素没食子酸酯（EGCG）、表儿茶素（EC）和矢车菊素-3-葡萄糖苷（Mlv-3-glc）作为抑制剂在酶测定中进行了研究。通过紫外/可见光谱法检测 CNP。数据表明，抑制剂的强度依次降低：EGCG > Mlv-3-glc > EC > PHL ∼ CA。等温滴定量热法检测到的底物转化支持这些结果。除 CA 和 EGCG 外，所有 PPs 均表现出混合抑制，其中竞争性比例占主导地位。饱和转移差异 NMR 的研究表明，PPs 与 α-淀粉酶的相互作用主要基于与芳香族或共轭系统的相互作用。可以发现共轭系统的程度与 PP 的 IC 之间存在相关性。
