Inhibitory mechanism of novel allosteric inhibitor, Chinese bayberry (Myrica rubra Sieb. et Zucc.) leaves proanthocyanidins against α-glucosidase

• Published in: Journal of functional foods Vol. 56; pp. 286 - 294
• Main Authors: Wang, Mengting, Jiang, Jing, Tian, Jinhu, Chen, Shiguo, Ye, Xingqian, Hu, Yaqin, Chen, Jianchu
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-05-2019; Elsevier
• Subjects: Bayberry leaves proanthocyanidins (BLPs); Fluorescence spectroscopy; Inhibitory; Molecular docking; α-Glucosidase; Fluorescence spectroscopy; α-Glucosidase; Inhibitory; Bayberry leaves proanthocyanidins (BLPs); Molecular docking
• ISSN: 1756-4646; 2214-9414
• DOI: 10.1016/j.jff.2019.03.026

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•Chinese bayberry leaves proanthocyanidins (BLPs) is a polymer with terminal and most extension units of EGCG.•BLPs is a high potential inhibitor to α-glucosidase.•BLPs exhibits a noncompetitive-type inhibition manner.•BLPs mainly binds to α-glucosidase to form a complex inducing conformational changes.•BLPs interacts with some amino acid residues located on an allosteric site of α-glucosidase.
α-Glucosidase is a key enzyme related to starch digestion and type-2 diabetes. In the present study, the inhibition effect and the underlying mechanism of Chinese bayberry leaves proanthocyanidins (BLPs) on α-glucosidase were investigated by enzyme kinetic analysis, multi-spectroscopy and molecular docking simulation. The results revealed that BLPs was a high potential noncompetitive-type inhibitor of α-glucosidase with the half maximal inhibitory concertation (IC50) value of 0.037 ± 0.001 mg mL−1 and acarbose equivalent (AE) of 517.01 mmol AE g−1. What’s more, BLPs may interact with some amino acids surrounded in the allosteric site of α-glucosidase to form a complex driven by hydrogen bonding and hydrophobic interaction, and thus change the structure and microenvironment of α-glucosidase, leading to the decrease of activity of α-glucosidase. The present study suggested that BLPs as epigallocatechin-3-O-gallate (EGCG) polymers could be a novel α-glucosidase inhibitor and had potential to be further used in functional food or anti-diabetic drug.