Mechanisms of Antioxidant Activities of Fullerenols from First-Principles Calculation

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 C60#nbsp;fullerenols are not completely understood. Using density functional theory calculations, we investigated#nbsp;•OH-, O2•–, and H2O2-scavenging mechanisms of C60#nbsp;fullerenols and the correlations between hydroxyl distributions and radical-scavenging ability. For scavenging#nbsp;•OH and O2•-, H•#nbsp;donation and electron transfer via hydrogen bonds, respectively, are the dominant mechanisms for C60#nbsp;fullerenols. Although the obtained fullerenols simultaneously contain radicals and anions, there is an isolated OH anion which possesses the activity of eliminating H2O2. The#nbsp;•OH-scavenging activity depends on the distribution of hydroxyls according to the calculations for ten C60(OH)24#nbsp;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 sp2#nbsp;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.

https://pubmed.ncbi.nlm.nih.gov/30244577/