School of Food Science & Technology, Jiangnan University, Wuxi, Jiangsu 214122, China.
School of Food Science & Technology, Jiangnan University, Wuxi, Jiangsu 214122, China; The State Key Laboratory of Food Science & Technology, Jiangnan University, Wuxi, Jiangsu 214122, China.
Int J Biol Macromol. 2021 Mar 1;172:503-514. doi: 10.1016/j.ijbiomac.2021.01.070. Epub 2021 Jan 15.
The study aimed to reveal the different mechanisms of delaying starch digestion by ECG, EGCG and Procyanidin based on the perspective of α-amylase-flavanol interaction and starch-flavanol interaction. The interaction characteristics of flavanols with α-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 α-amylase were 172.21 ± 0.22, 732.15 ± 0.13 and 504.45 ± 0.19 μg/mL according to the results of α-amylase inhibition experiment, respectively. ECG and Procyanidin showed mixed inhibition against α-amylase, while EGCG showed non-competition against α-amylase. However, thermodynamic parameters，computer-based docking and dynamic simulation proved that ECG and EGCG-α-amylase complexs were mainly driven by van der Waals and hydrogen bonds, while Procyanidin-α-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 α-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.
本研究旨在从α-淀粉酶-黄烷醇相互作用和淀粉-黄烷醇相互作用的角度揭示 ECG、EGCG 和原花青素延缓淀粉消化的不同机制。从酶抑制、动力学、荧光猝灭、圆二色性（CD）和计算机模拟五个方面研究了黄烷醇与α-淀粉酶的相互作用特征。根据α-淀粉酶抑制实验的结果，黄烷醇（ECG、EGCG 和原花青素）对α-淀粉酶的 IC50 分别为 172.21±0.22、732.15±0.13 和 504.45±0.19μg/mL。ECG 和原花青素对α-淀粉酶表现出混合抑制，而 EGCG 对α-淀粉酶表现出非竞争抑制。然而，热力学参数、基于计算机的对接和动态模拟证明，ECG 和 EGCG-α-淀粉酶复合物主要由范德华力和氢键驱动，而原花青素-α-淀粉酶复合物主要由疏水相互作用驱动。此外，通过淀粉-碘络合物光谱法表明，黄烷醇不仅通过与α-淀粉酶结合，还通过与淀粉结合来抑制淀粉的消化。因此，黄烷醇作为一种基于淀粉的食品添加剂，具有作为糖尿病辅助治疗的潜力。
