Antioxidative activity of caffeic acid: Mechanistic DFT study

• Main Authors: Redžepović Izudin, Marković Svetlana, Tošović Jelena
• Format: Article
• Language: English
• Published: University of Kragujevac, Faculty of Science 2017-01-01
• Series: Kragujevac Journal of Science
• Subjects: activation energies; reaction energies; rate constants; M06-2X/6-311++G(d,p) theoretical model; CPCM solvation model
• Online Access: http://scindeks-clanci.ceon.rs/data/pdf/1450-9636/2017/1450-96361739109R.pdf

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.