A deeper insight on the radical scavenger activity of two simple coumarins toward OOH radical

作者：Marino T^*; Russo N; Galano Annia

来源：Computational and Theoretical Chemistry, 2016, 1077: 133-138.

DOI：10.1016/j.comptc.2015.12.010

• OOH radical scavenging activity
• Antioxidant activity
• Hydroxycoumarins
• Density functional theory
• Kinetic constants

The antioxidant properties of 7-hydroxy-5-methoxy-4-methyl-2H-chromen-2-one (system a) and 5-hy droxy-7-methoxy-4-methyl-2H-chromen-2-one (system b) have been explored and rationalized by density functional theory. Quantum mechanics based test for overall free radical scavenging activity (QM-ORSA) protocol has been employed to account for their radical-scavenging capacity against hydroperoxyl radical in aqueous and lipid solutions. Three different reaction mechanisms have been considered. They are the single electron transfer (SET), the hydrogen atom transfer (HAT) and the radical adduct formation (RAF). From both, thermodynamic and kinetic points of view, our calculations suggest that HAT is the most favored reaction mechanism for the free radical scavenging activity of the studied systems. Kinetic rate constants indicate that system a is a more efficient antioxidant than system b in non polar media, while the opposite trend is found in aqueous solution. These results indicate that both the polarity of the environment, and the position of the methoxy and hydroxy groups in the coumarin structure influence the activity of this kind of compounds.

• 出版日期2016-2-1