Antioxidative activity of caffeic acid – mechanistic DFT study Keywords: activation energies, reaction energies, rate constants, M06-2X/6-311++G(d,p) theoretical model, CPCM solvation model info:eu-repo/semantics/article eng Kragujevac Journal of Science 39 Redžepović, Izudin Marković, Svetlana Tošović, Jelena All rights reserved 2017 Abstract: This paper reports the results of comprehensive mechanistic investigations of the hydrogen atom transfer (HAT), radical adduct formation (RAF), single electron transfer – proton transfer (SET-PT), and sequential proton loss electron transfer (SPLET) mechanisms of caffeic acid (CA). The goals of the work were achieved by simulating the reactions of CA with hydroxyl radical in benzene and water solutions. It was found that SET-PT is not a favourable antioxidative mechanism of CA. On the other hand, HAT and RAF are competitive, because HAT pathways yield thermodynamically more stable radical products, and RAF pathways require smaller activation barriers. In polar basic environment SPLET is a probable antioxidative mechanism of CA, with exceptionally large rate. application/pdf 566730 bytes https://phaidrabg.bg.ac.rs/o:28941 doi:10.5937/KgJSci1739109R ISSN: 1450-9636