Three flavanols delay starch digestion by inhibiting α-amylase and binding with starch

The study aimed to reveal the different mechanisms of delaying starch digestion by ECG, EGCG and Procyanidin based on the perspective of alpha-amylase-flavanol interaction and starch-flavanol interaction. The interaction characteristics of flavanols with alpha-amylase were studied from five aspects: enzyme inhibition, kinetics, fluorescence quenching, circular dichroism (CD) and computer simulation. The IC50 of flavanols (ECG, EGCG and Procyanidin) against alpha-amylase were 172.21 +/- 0.22, 732.15 +/- 0.13 and 504.45 +/- 0.19 mu g/mL according to the results of alpha-amylase inhibition experiment, respectively. ECG and Procyanidin showed mixed inhibition against alpha-amylase, while EGCG showed non-competition against alpha-amylase. However, thermodynamic parameters, computer-based docking and dynamic simulation proved that ECG and EGCG-alpha-amylase complexs were mainly driven by van der Waals and hydrogen bonds, while Procyanidin-alpha-amylase complexs was driven by hydrophobic interaction. In addition, it was indicated, by means of starch-iodine complex spectroscopy, that flavanols inhibited the digestion of starch not only through bind with alpha-amylase but also through bind with starch. Thus, flavanols as a starch-based food additive have the potential to be employed as adjuvant therapy for diabetes. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

The study investigated the mechanisms of delaying starch digestion by ECG, EGCG and Procyanidin through interactions with alpha-amylase and starch. Flavanols showed different inhibition patterns against alpha-amylase, with ECG and Procyanidin demonstrating mixed inhibition and EGCG showing non-competitive inhibition. Thermodynamic parameters and computer simulations revealed the driving forces of these interactions, indicating potential applications of flavanols as adjuvant therapy for diabetes.