Wang Zhenzhen, Gao Xingfa, Zhao Yuliang
CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety , Institute of High Energy Physics, Chinese Academy of Sciences , Beijing 100049 , China.
University of Chinese Academy of Sciences , Beijing 100049 , China.
J Phys Chem A. 2018 Oct 18;122(41):8183-8190. doi: 10.1021/acs.jpca.8b06340. Epub 2018 Oct 3.
Fullerenols possess excellent antioxidant activity, in which they can scavenge all of the major physiologically relevant reactive oxygen species (ROS). However, the underlying ROS-scavenging mechanisms of C fullerenols are not completely understood. Using density functional theory calculations, we investigated OH-, O-, and HO-scavenging mechanisms of C fullerenols and the correlations between hydroxyl distributions and radical-scavenging ability. For scavenging OH and O, H donation and electron transfer via hydrogen bonds, respectively, are the dominant mechanisms for C fullerenols. Although the obtained fullerenols simultaneously contain radicals and anions, there is an isolated OH anion which possesses the activity of eliminating HO. The OH-scavenging activity depends on the distribution of hydroxyls according to the calculations for ten C(OH) isomers. Fullerenols, in which the distribution of hydroxyls leads to low redox potential (ε) values, possess high scavenging activity. For the nonmagnetic fullerenols, activity relies on the number of sp substructures, in which the greater their number is, the lower the activity of the fullerenols. The results will be of fundamental importance in understanding the antioxidant activities of fullerenols.
富勒醇具有出色的抗氧化活性，能够清除所有主要的生理相关活性氧（ROS）。然而，碳富勒醇潜在的ROS清除机制尚未完全明确。我们运用密度泛函理论计算方法，研究了碳富勒醇对OH-、O-和HO-的清除机制以及羟基分布与自由基清除能力之间的相关性。对于清除OH和O，碳富勒醇的主要机制分别是通过氢键进行氢供体作用和电子转移。尽管所得到的富勒醇同时含有自由基和阴离子，但存在一个具有消除HO活性的孤立OH阴离子。根据对十种C(OH)异构体的计算，OH清除活性取决于羟基的分布。羟基分布导致低氧化还原电位（ε）值的富勒醇具有较高的清除活性。对于非磁性富勒醇，活性依赖于sp子结构的数量，其数量越多，富勒醇的活性越低。这些结果对于理解富勒醇的抗氧化活性具有至关重要的意义。
