Comparative density functional study of antioxidative activity of thehydroxybenzoic acids and their anions

Abstract

Hydroxybenzoic acids (HBAs) and their anions play an important role in the food and pharmaceuticalindustries because of their antioxidant activity. In this study, we examined the mechanisms of the free radical scavengingaction of HBAs and their anions using density functional theory (DFT) methods. Reaction enthalpies related to themechanisms of free radical scavenging by the investigated species were calculated by DFT methods in water, DMSO,pentylethanoate, and benzene. Hydrogen atom transfer (HAT) is a preferred reaction pathway in benzene, whilesequential proton loss electron transfer (SPLET) is a predominant reaction pathway in polar solvents, water, and DMSOfor all species. For anions of HBAs, HAT and SPLET mechanisms in pentylethanoate are competitive, while SPLET isthe most probable pathway in the case of HBAs.