基于密度泛函理论的生命体水环境下GA分子消除OH的反应机制OA

The study investigated reaction mechanisms of gallic acid(GA)with hydroxyl radicals and hydroxyl radical-water clusters(OH and OH·H2O)in a physiological environment(aqueous phase at 310.15 K and 1.013 ×105 Pa)using the M06-2X method of density functional theory combined with the SMD solvation model from the self-consistent reaction field theory.The reactions between GA and OH proceed via three channels:Hydrogen abstraction by OH,OH addition to carbon,and single electron transfer from GA to OH.Calculations show that for the hydrogen abstraction channel,the reaction where OH(or OH·H2O)abstracts the hydroxyl hydrogen is the most favorable.Both are barrierless processes accompanied by significant exothermic effects.For the addition channel,the addition of OH(or OH·H2O)to the aromatic ring carbon is the most favorable,with free energy barriers ranging from 24.4 to 58.8 kJ/mol,exhibiting significant exothermic effects.The single electron transfer process from GA to OH and OH·H2O is thermodynamically unfavorable and cannot occur.The results indicate that GA can eliminate OH radicals via hydrogen abstraction and addition reactions,demonstrating that gallic acid can serve as an effective hydroxyl radical scavenger.