This paper describes a theoretical comparative study of the antiradical properties of six aromatic compounds namely eugenol (EUG), safrole (SAF), myristicin (MYR), carvacrol (CAR), cinnamaldehyde (CIN), and isoeugenol (ISO) found in antioxidant essential oils. Using density functional theory (DFT) calculations, some structural characteristics such as molecular descriptors, frontier molecular orbitals, and molecular electrostatic potential have been studied. Three main antiradical mechanisms, hydrogen atom transfer (HAT), single electron transfer proton transfer (SETPT, and sequential proton loss electron transfer (SPLET) have been also investigated. In addition, the Gibbs free energies related to the reactions of the studied compounds with two reactive oxidant species (HO• and HOO•) have been computed. Throughout the study, the implicitly of polar and nonpolar solvents (water and benzene) has been taken into account. It was found that EUG, SAF, CIN, and ISO scavenge free radicals by means of a CH bond, while CAR and ISO by means of an OH bond. In the gas and benzene phases, all the studied compounds prefer to undergo HAT mechanism, while in water, SPLET is more favoured for CIN, CAR, and ISO and both HAT and SPLET are possible for EUG, SAF, and MYR. In all the studied mediums, the sequence of the antiradical potential is: MYR ≈ SAF ≈ ISO ≈ EUG > CAR > CIN. This order is in line with the available experimental results.

中文翻译：

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DFT研究了一些由抗氧化剂精油衍生的芳香族化合物的抗自由基性能：CH键与OH键。

本文描述了在抗氧化剂必需物中发现的六种芳族化合物的基本理论比较研究，即丁香酚（EUG），黄樟脑（SAF），肉豆蔻素（MYR），香芹酚（CAR），肉桂醛（CIN）和异丁香酚（ISO）油。使用密度泛函理论（DFT）计算，研究了一些结构特征，例如分子描述符，前沿分子轨道和分子静电势。还研究了三种主要的反自由基机理：氢原子转移（HAT），单电子转移质子转移（SETPT）和顺序质子损失电子转移（SPLET），此外，吉布斯自由能与所研究化合物与已经计算出两种活性氧化剂（HO•和HOO•）。在整个研究过程中，隐含的极性和非极性溶剂（水和苯）已被考虑在内。发现EUG，SAF，CIN和ISO通过CH键清除自由基，而CAR和ISO通过OH键清除自由基。在气相和苯相中，所有研究的化合物均倾向于经历HAT机理，而在水中，SPLET更适合CIN，CAR和ISO，EUG，SAF和MYR均适合HAT和SPLET。在所有研究的介质中，抗自由基能力的顺序为：MYR≈SAF≈ISO≈EUG> CAR> CIN。此顺序与可用的实验结果一致。所有研究的化合物都倾向于经历HAT机理，而在水中，SPLET更适合CIN，CAR和ISO，EAG，SAF和MYR都可以使用HAT和SPLET。在所有研究的介质中，抗自由基能力的顺序为：MYR≈SAF≈ISO≈EUG> CAR> CIN。此顺序与可用的实验结果一致。所有研究的化合物都喜欢经历HAT机理，而在水中，SPLET更适合CIN，CAR和ISO，EHAT，SAF和MYR都可以使用HAT和SPLET。在所有研究的介质中，抗自由基能力的顺序为：MYR≈SAF≈ISO≈EUG> CAR> CIN。此顺序与可用的实验结果一致。