基于实验和密度泛函理论研究EGCG与Zn(Ⅱ)的相互作用

Study on the Interaction of EGCG with Zn(Ⅱ) Based on Experiments and Density Functional Theory

用紫外-可见（UV-Vis）吸收光谱和1H核磁共振（NMR）谱研究了茶多酚类衍生物表没食子儿茶素没食子酸酯（EGCG）与Zn（Ⅱ）离子的相互作用，并用密度泛函理论（DFT）计算了EGCG与Zn（Ⅱ）离子络合前后的空间结构及其紫外和核磁共振谱．实验与理论研究结果表明：EGCG主要构象是其芳香B环以e键（平伏键）及芳香D环以a键（直立键）形式共同与C环链接．EGCG通过其芳香D环上酚羟基与Zn（11）离子相互作用，生成稳定的Zn（Ⅱ）与EGCG摩尔比为1：1的Zn（Ⅱ）-EGCG四面体络合物．

The interaction between the tea polyphenols derivative （-）-epigallocatechin-3-gallate （EGCG） and Zn（Ⅱ） was investigated by ultraviolet visible （UV-Vis） spectroscopy and liquid-state 1H nuclear magnetic resonance （NMR）. In addition, density functional theory （DFT）-based UV and chemical shifts were calculated to view insight into the complex structure and property. The main conformer of EGCG is an aromatic B-ring in an e-bond （equatorial bond） and an aromatic D-ring in an a-bond （axial bond） and these are linked to the C-ring. In addition, the Zn（Ⅱ） ion can coordinate with the phenolic hydroxyl groups in the D-ring and form a steady tetrahedral Zn（Ⅱ）-EGCG complex in a 1：1 molar ratio.