Theoretical insights into the radical scavenging performance of common anti-agers from both kinetic and thermodynamic perspectives

Abstract

In this article, the radical scavenging performance of eight anti-agers (TMQ, ETMQ, DCD, o-MBp24, o-MBp14, p-BBp14, DNPD, and 6PPD) was benchmarked by the experimental residue rates of the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals, followed by the theoretical investigation from the perspective of both kinetic and thermodynamic factors. Kinetically, anti-agers with lower Gibbs free energy barriers (ΔG≠) presumably exhibit higher scavenging performance. Moreover, the scavenging performance is also controlled by the thermodynamic feature, that is, the small difference in Gibbs free energy between products and reactants (ΔG(R → P)) promotes the scavenging performance. Therefore, the ΔG≠×ΔG(R → P) indicator considering both kinetic and thermodynamic contributions was proposed here to comprehensively explain the difference in the scavenging performance of anti-agers. The strong positive correlation between experimental residues and ΔG≠×ΔG(R → P) values (R2 = 0.806) revealed that the ΔG≠×ΔG(R → P) indicator promises to be a reliable metric to theoretically assess the scavenging performance of anti-agers.