Centre de Recherche en Sciences Pharmaceutiques (CRSP), 25000, Constantine, Algeria.
Centre de Recherche Scientifique et Technique en Analyses Physico-Chimiques (CRAPC), Tipaza, Algeria.
J Mol Model. 2022 Aug 1;28(8):240. doi: 10.1007/s00894-022-05223-7.
The structural and antioxidant activity of two flavonols, namely, Fisetin and Robinetin, have been investigated employing the density functional theory (DFT) using B3LYP functional and 6-311++G (d, p) basis set. The calculations were performed in the gas phase and under the solvent effect of water, dimethylsulfoxide (DMSO), methanol, and benzene. The Hydrogen-Atom Transfer (HAT), single Electron Transfer Followed by Proton Transfer (SET-PT), and sequential Proton Loss Electron Transfer (SPLET) mechanisms were investigated to rationalize the radical scavenging capacities and to identify the favored antioxidant mechanism. Hence, the bond dissociation enthalpies (BDE) ionization potential (IP), IE, proton dissociation enthalpy (PDE), proton affinity (PA), and electron Transfer enthalpy (ETE) related to each mechanism were reported and discussed in function of the solvent effect. For both flavonols, the results showed that 4'-OH hydroxyl is the preferred active site following the trend 4'-OH > 3'-OH > 3-OH > (5'-OH) > 7-OH. Besides, the HAT mechanism is energetically the most favored pathway. The energetically favored solvents follow the trends water > DMSO > benzene > methanol and benzene > DMSO > methanol > water, for Fisetin and Robinetin, respectively.
采用密度泛函理论（DFT），使用 B3LYP 函数和 6-311++G（d，p）基组，研究了两种类黄酮，即非瑟酮和罗宾汀的结构和抗氧化活性。在气相中和水、二甲基亚砜（DMSO）、甲醇和苯的溶剂效应下进行了计算。研究了氢原子转移（HAT）、单电子转移随后质子转移（SET-PT）和顺序质子损失电子转移（SPLET）机制，以合理化自由基清除能力，并确定首选的抗氧化机制。因此，报告并讨论了与每种机制相关的键离解焓（BDE）、电离能（IP）、IE、质子离解焓（PDE）、质子亲合能（PA）和电子转移焓（ETE），并考虑了溶剂效应的影响。对于这两种类黄酮，结果表明 4'-OH 羟基是首选的活性位点，遵循以下趋势 4'-OH > 3'-OH > 3-OH > （5'-OH）> 7-OH。此外，HAT 机制在能量上是最有利的途径。对于非瑟酮和罗宾汀，最有利于能量的溶剂分别遵循水 > DMSO > 苯 > 甲醇和苯 > DMSO > 甲醇 > 水的趋势。
