氧化白藜芦醇清除自由基活性的密度泛函理论研究

Density functional theory study on the free radical scavenging of oxyresveratrol

采用密度泛函理论(DFT)的方法,分析了氧化白藜芦醇分子酚羟基在不同溶剂中清除自由基活性能力大小,对其三种抗氧化机制:H原子转移(HAT)机制、逐步电子转移质子转移(SET-PT)机制、质子优先损失电子转移(SPLET)机制进行了研究,探讨了在气相中不同位置酚羟基清除·OH、·OOH自由基的抗氧化机理。计算结果表明,在任何溶剂中氧化白藜芦醇分子C4’位的酚羟基活性最高,在气相和苯中HAT机制是清除自由基活性的最主要机制,在极性溶剂中SET-PT机制是热力学上最有利的途径,而在所有环境中SPLET机制都不是最主要的机制。

In this paper,the density functional theory（ DFT） method was used to analyze the activity on the free radical scavenging for different phenol hydroxyl free radicals of oxyresveratrol in different solvents. Three potential working mechanisms, hydrogen atom transfer（ HAT） , stepwise electron transfer proton transfer（ SET-PT） and sequential proton loss electron transfer（ SPLET） have been investigated. Possible reaction mechanism between · OH and· 00H with oxyresveratrol were also discussed. The results showed that the activation energies of hydrogen abstraction from 4,-OH was the smallest and the 4,-OH of oxyresveratrol was the most activist site. HAT would be the most favourable mechanism in the gas and benzene phases, whereas the SPLET mechanism is the thermody-namically preferred pathway in polar media and the SET-PT mechanism is not the main mechanism in all environments.