Data_Sheet_1_Quantum Mechanical Predictions of the Antioxidant Capability of Moracin C Isomers.docx

The antioxidant capability of moracin C and iso-moracin C isomers against the OOH free radical was studied by applying density functional theory (DFT) and choosing the M05-2X exchange-correlation functional coupled with the all electron basis set, 6-311++G(d,p), for computations. Different reaction mechanisms [hydrogen atom transfer (HAT), single electron transfer (SET), and radical adduct formation (RAF)] were taken into account when considering water- and lipid-like environments. Rate constants were obtained by applying the conventional transition state theory (TST). The results show that, in water, scavenging activity mainly occurs through a radical addition mechanism for both isomers, while, in the lipid-like environment, the radical addition process is favored for iso-moracin C, while, redox- and non-redox-type reactions can equally occur for moracin C. The values of pKa relative to the deprotonation paths at physiological pH were predicted in aqueous solution.

本研究通过密度泛函理论（DFT）对莫拉辛C及其异构体莫拉辛C的抗氧化能力进行了研究，计算中选用了M05-2X交换关联泛函与全电子基组6-311++G(d,p)。在考虑水相和脂质相环境时，纳入了不同的反应机制，包括氢原子转移（HAT）、单电子转移（SET）和自由基加成（RAF）。通过传统的过渡态理论（TST）获得了速率常数。结果显示，在水中，两种异构体的清除活性主要通过自由基加成机制实现，而在脂质相环境中，对于莫拉辛C异构体，自由基加成过程更为有利，而对于莫拉辛C，氧化还原和非氧化还原型反应可以同时发生。在水中溶液中，相对于生理pH值下的去质子化路径，预测了pKa值。