Abstract: All possible conformations of trans-resveratrol were optimized by using DFT B3LYP/6-31g, and natural bond analysis on the most stable conformation was carried out, the result shows that the most active position in the hydroxyl radical scavenging of trans-resveratrol was the phenolic hydroxyl in the single hydroxyl circle. The mechanism of this reaction has been theoretically studied at DFT B3LYP/6-31g. The IRC also has been carried out at the same theoretical level. The results show that the hydroxyl of trans-resveratrol reacted with hydroxyl radical to produce H₂O. The energy of stationary points in the reaction path shows that the energy of reactant was E₁=173.5193 kJ/mol, higher than that of the reactant complex, the activation energy was E_a=16.5143 kJ/mol, and the energy of product was E₂=51.8799 kJ/mol, higher than that of the reactant complex. So when the reaction complex formed it would be trasformed into transition state and product immediately.

Key words: Resveratrol, Antioxidation, Hydroxyl radical, DFT, IRC