The naturally occurring stilbenes piceatannol and its derivatives are excellent antioxidants. In this work, the antioxidative activities of piceatannol and different piceatannol derivatives have been investigated using the density functional theory (DFT) method based on three widely accepted radical scavenging mechanisms, namely, the hydrogen atom transfer (HAT), single electron transfer followed by proton transfer (SET-PT) and sequential proton loss electron transfer (SPLET). The gas and four solvent phases, namely, bond dissociation enthalpy (BDE), ionization potential (IP), proton dissociation enthalpy (PDE), proton affinity (PA) and electron transfer enthalpy (ETE), related to these mechanisms were calculated to elucidate the antioxidative capacities of the investigated compounds. This work focuses specifically on the thermodynamically preferred mechanism, antioxidative site and antioxidative activity order of the investigated stilbenes. The substituted effects of the methyl group and prenyl group on the chemical properties of the remaining OH and CH groups are also analysed. This work confirms the vital role of the OH and CH groups on free radical scavenging of piceatannol and its derivatives.

中文翻译：

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云杉醇及其不同衍生物的抗氧化活性：抗氧化机理分析

天然存在的芪类 piceatannol 及其衍生物是极好的抗氧化剂。在这项工作中，基于三种广泛接受的自由基清除机制，即氢原子转移 (HAT)、单电子转移和质子转移，使用密度泛函理论 (DFT) 方法研究了云杉醇和不同的云杉醇衍生物的抗氧化活性。转移 (SET-PT) 和顺序质子损失电子转移 (SPLET)。计算了与这些机制相关的气相和四个溶剂相，即键解离焓 (BDE)、电离势 (IP)、质子解离焓 (PDE)、质子亲合力 (PA) 和电子转移焓 (ETE)，以阐明所研究化合物的抗氧化能力。这项工作特别关注所研究的芪的热力学优选机制、抗氧化位点和抗氧化活性顺序。还分析了甲基和异戊二烯基对剩余 OH 和 CH 基团的化学性质的取代影响。这项工作证实了 OH 和 CH 基团在 piceatannol 及其衍生物的自由基清除中的重要作用。