College of Biosystems Engineering and Food Science, Zhejiang University, Zhejiang Key Laboratory for Agro-Food Processing, Fuli Institute of Food Science, Zhejiang R&D Center for Food Technology and Equipment, Hangzhou 310058, People's Republic of China.
College of Biosystems Engineering and Food Science, Zhejiang University, Zhejiang Key Laboratory for Agro-Food Processing, Fuli Institute of Food Science, Zhejiang R&D Center for Food Technology and Equipment, Hangzhou 310058, People's Republic of China; Ningbo Research Institute, Zhejiang University, Ningbo, 315100, People's Republic of China.
Bioorg Chem. 2020 Aug;101:104029. doi: 10.1016/j.bioorg.2020.104029. Epub 2020 Jun 19.
Chinese bayberry leaves proanthocyanidins (BLPs) belongs to the prodelphinidin category with potent EGCG unit, whose inhibition effect on α-amylase and their interaction were investigated by in vitro digestion and enzyme kinetic analysis, multi fluorescence spectroscopies (fluorescence quenching, synchronous fluorescence, and three-dimensional fluorescence), circular dichroism spectra, Fourier transform infrared spectroscopy and in silico modelling. The results revealed that BLPs was a mixed inhibitor to α-amylase with the IC value of 3.075 ± 0.073 μg/mL. BLPs could lead to a static fluorescence quenching of α-amylase, mainly by means of interacting with amino acids (mainly Try and Tyr residues) in one site on α-amylase molecule under the action of hydrogen bonding and/or Van der Waals force. This interaction further induced the change of secondary conformational structure, functional group structure and hydrophobicity of α-amylase, thus resulting in lowering activity. Molecular docking simulated that this binding occurred in a cavity on the surface of the α-amylase molecule, and BLPs trimer showed a relatively high binding energy. The present study provided a new insight of BLPs as an α-amylase inhibitor, which could be considered in anti-diabetic therapy.
杨梅叶原花青素（BLPs）属于原翠雀素类，具有较强的 EGCG 单元，通过体外消化和酶动力学分析、多荧光光谱（荧光猝灭、同步荧光和三维荧光）、圆二色光谱、傅里叶变换红外光谱和计算机模拟研究了其对α-淀粉酶的抑制作用及其相互作用。结果表明，BLPs 对α-淀粉酶是一种混合抑制剂，IC 值为 3.075±0.073μg/mL。BLPs 可通过氢键和/或范德华力在α-淀粉酶分子上的一个位点与α-淀粉酶中的氨基酸（主要是色氨酸和酪氨酸残基）相互作用，导致α-淀粉酶的静态荧光猝灭，主要是通过氢键和/或范德华力。这种相互作用进一步诱导了α-淀粉酶二级构象结构、官能团结构和疏水性的变化，从而降低了其活性。分子对接模拟表明，这种结合发生在α-淀粉酶分子表面的一个腔中，BLPs 三聚体显示出相对较高的结合能。本研究为 BLPs 作为α-淀粉酶抑制剂提供了新的见解，可考虑用于抗糖尿病治疗。
