Departamento de Química, Universidade Federal de Mato Grosso, Cuiabá, Mato Grosso, 78060-900, Brazil.
Instituto Federal de Educação, Ciência e Tecnologia de Mato Grosso, Rondonópolis, Mato Grosso, 78721-520, Brazil.
J Mol Model. 2019 Mar 28;25(4):103. doi: 10.1007/s00894-019-3969-8.
The strategy of investigating the antioxidant potential of flavonols through the explicit modeling of chemical reactions (initiated to be employed in a previous work from our group) was taken further in this work. Therefore, a theoretical investigation on the reaction between fisetin and 2,2-diphenyl-1-picrylhydrazyl (DPPH) is presented. All the computations were performed using the density functional theory with the B3LYP functional along with the 6-31G(d,p) basis set. Structural, energetic quantities (ΔG and ΔG), and reaction rates were probed in order to provide information on the antioxidant activity and to explore the contributions of each hydroxyl group to the referred property. According to the results obtained for the thermodynamic properties, fisetin presents antioxidant potential similar to quercetin (behavior that is also observed experimentally). In addition, the order of contribution of each OH group to the antioxidant potential was found to be 4'-ArOH (the most contributor, presenting ΔG = -5.17 kcal/mol) → 3'-ArOH (ΔG = -3.35 kcal/mol) → 3-ArOH (ΔG = -1.64 kcal/mol) → 7-ArOH (ΔG = 7.72 kcal/mol). These observations are in consistent agreement with the outcomes of other computational investigations performed using bond dissociation enthalpies (BDEs) as descriptors for the antioxidant activity. Therefore, the methodology employed in this work can be used as an alternative for probing antioxidant potential of compounds derived from fisetin. Graphical Abstract Illustrative scheme of the PES mapping in terms of hydrogen atom transfer from fisetin 3-ArOH to the nitrogen centered DPPH.
本工作进一步采用明确模拟化学反应（前一工作中采用的策略）来研究黄酮醇的抗氧化潜力。因此，本文提出了一种关于非瑟酮与 2,2-二苯基-1-苦基肼（DPPH）之间反应的理论研究。所有计算均采用密度泛函理论（B3LYP 泛函）和 6-31G(d,p)基组进行。为了提供抗氧化活性的信息并探讨每个羟基对该性质的贡献，研究了结构、能量参数（ΔG 和 ΔG）和反应速率。根据热力学性质的结果，非瑟酮具有与槲皮素相似的抗氧化潜力（实验中也观察到这种行为）。此外，还发现每个 OH 基团对抗氧化潜力的贡献顺序为 4'-ArOH（最具贡献者，ΔG = -5.17 kcal/mol）→3'-ArOH（ΔG = -3.35 kcal/mol）→3-ArOH（ΔG = -1.64 kcal/mol）→7-ArOH（ΔG = 7.72 kcal/mol）。这些观察结果与使用键离解焓（BDE）作为抗氧化活性描述符进行的其他计算研究的结果一致。因此，本工作中采用的方法可用于探测非瑟酮衍生化合物的抗氧化潜力。
