Issue 5, 2020

Number of galloyl moieties and molecular flexibility are both important in alpha-amylase inhibition by galloyl-based polyphenols

Abstract

The inhibition of porcine pancreatic α-amylase (PPA) by 9 galloyl-based polyphenols was evaluated via initial digestion velocity, IC50, inhibition kinetics, fluorescence quenching and molecular docking studies. The results show that the polyphenols with free galloyl moieties (GMs) exhibited a much higher inhibition effect than that with bound GMs. The inhibition was competitive mode and increased with an increase in the number of free GMs. Interestingly, all the constants that indicate the binding affinity of polyphenols to PPA, including the reciprocal of the competitive inhibition constant (1/Kic), fluorescence quenching constant (KFQ) and binding energy (Eb), increased with an increase in the number of free GMs. Besides, the respective order of 1/Kic, KFQ and Eb for the galloyl-based polyphenols was contrary to that of IC50, indicating that the polyphenol–PPA binding interactions resulted in enzyme inhibition. In addition, the binding interactions were suggested to result from the hydrogen bonding and π–π conjugation forces between the free GMs and amino acid residues at the active sites of PPA, whereas the chemical linkage of the GMs with additional polyphenol groups limited these interactions. Furthermore, the hypoglycemic effects of two polyphenols with 5 free GMs indicate that GMs may be considered a functional fragment involved in the alleviation of the symptoms of type II diabetes through α-amylase inhibition.

Graphical abstract: Number of galloyl moieties and molecular flexibility are both important in alpha-amylase inhibition by galloyl-based polyphenols

Article information

Article type
Paper
Submitted
20 Nov 2019
Accepted
06 Apr 2020
First published
07 Apr 2020

Food Funct., 2020,11, 3838-3850

Number of galloyl moieties and molecular flexibility are both important in alpha-amylase inhibition by galloyl-based polyphenols

J. Cao, Y. Zhang, L. Han, S. Zhang, X. Duan, L. Sun and M. Wang, Food Funct., 2020, 11, 3838 DOI: 10.1039/C9FO02735A

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements