Effects of hydroxyl group, glycosylation and solvents on the antioxidant activity and mechanism of maclurin and its derivatives: Theoretical insights

Maclurin (MAC) and its derivatives received increasing interest due to their diverse biological activities. However, understanding of their antioxidant properties remains insufficient. Herein, the antioxidant activity and mechanism of maclurin (MAC) and iriflophenone (IRF) as well as their glucosides, maclurin-3-C-glucoside (MAC-Glu) and iriflophenone-3-C-glucoside (IRF-Glu) were evaluated using density functional theory (DFT) approach based on descriptors involved in the double (2H+/2e-) radical-trapping processes. Effects of hydroxyl group, glycosylation, hydrogen bonding, and solvents were explored. Moreover, thermodynamic and free energy barrier calculations of MAC with hydroperoxyl (HOO•) radical have also been performed to further explore the radical-trapping behavior. Results showed that double hydrogen atom transfer (dHAT) mechanism represents the dominant pathway in the gas and non-polar phases, while double sequential proton loss electron transfer (dSPLET) is the prevailing mechanism in the polar media. Results also revealed the important role of ortho-dihydroxyl group and C-glycosylation on antiradical activity.