Evaluation of the Antiradical Properties of Phenolic Acids

• Main Authors: Olga Koroleva, Anna Torkova, Ilya Nikolaev, Ekaterina Khrameeva, Tatyana Fedorova, Mikhail Tsentalovich, Ryszard Amarowicz
• Format: Article
• Language: English
• Published: MDPI AG 2014-09-01
• Series: International Journal of Molecular Sciences
• Subjects: antioxitant capacity; antioxidant descriptors; quantum-chemical calculations; phenolic acids
• Online Access: http://www.mdpi.com/1422-0067/15/9/16351

Antioxidant capacity (AOC) against peroxyl radical and 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt (ABTS) radical cation was measured for a series of p-hydroxybenzoic (HB) and p-hydroxycinnamic (HC) acids at different pH. Quantum-chemical computation was performed using Gaussian 3.0 software package to calculate the geometry and energy parameters of the same compounds. Significant correlations were revealed between AOC and a number of calculated parameters. The most significant AOC descriptors for the studied compounds against peroxyl radical were found to be HOMO energy, rigidity (η) and Mulliken charge on the carbon atom in m-position to the phenolic hydroxyl. The most significant descriptor of the antioxidant properties against the ABTS radical cation at рН 7.40 is electron transfer enthalpy from the phenolate ion. The mechanism of AOC realization has been proposed for HB and HC acids against both radicals.