Formation of phytosterol photooxidation products: A chemical reaction mechanism for light-induced oxidation
Formation of phytosterol photooxidation products: A chemical reaction mechanism for light-induced oxidation
复制标题
植物甾醇光氧化产物的形成：光诱导氧化的化学反应机制
DOI：
10.1016/j.foodchem.2020.127430
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发表时间：
2020
期刊：
影响因子：
8.8
通讯作者：
Xin Hong
中科院分区：
文献类型：
--
作者：
Bo-wen Yang;Bai-yi Lu;Ya-jing Zhao;Jin-yang Luo;Xin Hong
植物甾醇（PS）是一组分布在食物和植物中的甾醇，在那里它容易氧化。本论文以植物甾醇为研究对象，采用密度泛函理论（DFT）计算和实验相结合的方法，研究了植物甾醇的光氧化反应机理。在LED光照射下，这些植物甾醇的实验性光氧化产生了植物甾醇的前三种氧化物：6α-OH、7α-OH和7β-OH。密度泛函理论（DFT）的机理研究表明，单线态氧（1 O2）介导的光氧化（II型机理）产生的自由基加成到甾核B环上的C5和C6上，C7上的反应由C5产物通过重排途径引发。此外，C5，C6和C7的立体选择性为植物甾醇的光氧化提供了机理指导。这些工作对复杂食品基质中植物甾醇的氧化机理和植物甾醇的抗氧化技术进行了必要的探索性研究。
Phytosterols (PS) are a group of sterols distributed in foods and plants, where it is prone to oxidation. In this work, we studied the reaction mechanism of phytosterols, using density functional theory (DFT) calculation and experimental methods to study the photooxidation of phytosterols. Under LED light illumination, experimental photooxidation of these phytosterols gives rise to the prior three kind oxides of phytosterol: 6α-OH, 7α-OH, and 7β-OH. The mechanistic investigations by DFT suggest that singlet oxygen (1O2)-mediated photooxidation (Type II mechanism) generated radical adds to the C5 and C6 on the B Ring of steroid nucleus and reaction in C7 initiated from C5 products through rearrangement pathway. Furthermore, the stereoselectivity at C5, C6 and C7 provides a mechanistic guide for phytosterols photooxidation. These efforts are expected to serve as an essential exploratory study for the oxidation mechanism of phytosterols in the complex food matrix and antioxidation technology for phytosterols.