Department of Biology, The Josip Juraj Strossmayer University, Cara Hadrijana 8a, HR-31000 Osijek, Croatia.
Department of Chemical-Technological Sciences, State University of Novi Pazar, Vuka Karadžića bb, 36300 Novi Pazar, Serbia.
Food Chem. 2014;152:578-85. doi: 10.1016/j.foodchem.2013.12.025. Epub 2013 Dec 12.
The 1H(+)/1e(-) and 2H(+)/2e(-) proton-coupled electron transfer (PCET) processes of free radical scavenging by flavonoids were theoretically studied for aqueous and lipid environments using the PM6 and PM7 methods. The results reported here indicate that the significant contribution of the second PCET mechanism, resulting in the formation of a quinone/quinone methide, effectively discriminates the active from inactive flavonoids. The predictive potency of descriptors related to the energetics of second PCET mechanisms (the second O-H bond dissociation enthalpy (BDE2) related to hydrogen atom transfer (HAT) mechanism, and the second electron transfer enthalpy (ETE2) related to sequential proton loss electron transfer (SPLET) mechanism) are superior to the currently used indices, which are related to the first 1H(+)/1e(-) processes, and could serve as primary descriptors in development of the QSAR (quantitative structure-activity relationships) of flavonoids.
本文使用 PM6 和 PM7 方法，理论研究了黄酮类化合物在水相和脂相环境中清除自由基的 1H(+)/1e(-)和 2H(+)/2e(-)质子耦合电子转移 (PCET) 过程。结果表明，第二个 PCET 机制（导致醌/醌甲醚形成）的显著贡献，有效地区分了活性和非活性黄酮类化合物。与第二个 PCET 机制的能量相关的描述符（与氢原子转移 (HAT) 机制相关的第二个 O-H 键离解焓 (BDE2) 和与顺序质子丢失电子转移 (SPLET) 机制相关的第二个电子转移焓 (ETE2)）的预测能力优于目前使用的与第一个 1H(+)/1e(-)过程相关的指数，可作为黄酮类化合物 QSAR（定量构效关系）开发的主要描述符。
