水的溶剂效应对植物防晒剂UV-B吸收的影响

Solvent Effect of Water on the UV-B Absorption of Plant Sunscreen Agents

抵御UV-B(280~320nm)对地球生命至关重要.研究UV-B防晒分子周边的环境对UV-B吸收的影响有助于了解防晒剂的光吸收机制.水作为溶剂在细胞中无处不在,但是其对防晒剂吸收UV-B的影响还未被充分研究.本文基于第一性原理,重点研究了芥子酸酯及其相关植物防晒分子的UV-B吸收中水的溶剂作用.芥子酸酯阴离子对UV-B的吸收作用来自与其周边水溶剂环境的相互作用,因此其也是在实际环境中起到防晒功能的防晒物种。在第一性原理模拟中,隐式水溶剂模型可以提供溶剂化的介电环境,显式水溶剂模型可以与芥子酸酯阴离子形成氢键,这些因素都可以显著改变与芥子酸酯阴离子吸收UV-B相关的跃迁轨道性质.同时,发现了植物防晒剂的分子偶极矩可以作为衡量其UV-B吸收能力对周围极性环境敏感程度的指标.本工作为开发新型水溶性UV-B防晒剂提供了起点.

UV-B(280-320 nm)sunscreening is crucial for lives on Earth.Examining the role of surrounding of UV-B ter understand UV-B absorption.screening molecules can help us better is ubiquitous in cells as the solvent,but its impacts on UV-B absorption of sunscreen agents are underexplored.Herein,we report a firstprinciple study on UV-B absorption of sinapate malate(SM)and rele vant molecular species,with a focus on the solvent effect of water.The capability of UV-B screening by anions of SM,the proposed species for actual sunscreening,is shaped by water.Both the implicit water providing the dielectric environment of solvation and the explicit water molecules forming hydrogen bonding to SM anion can appreciably alter the nature of transition orbitals responsible to the UV-B absorption of the anion.Finally,we find the molecular dipole moment of an organic UV-B screening agent can be an indicator of its UV-B screening sensitivity to the surrounding water.Our work may serve as a starting point of developing new water-soluble UV-B screening agent.