A DFT method for the study of the antioxidant action mechanism of resveratrol derivatives.

Quantum-chemical calculations using DFT, have been performed to explain the molecular structure antioxidant activity relationship of resveratrol (RSV) (1) analogues: 3,4-dihydroxy-trans-stilbene (3,4-DHS) (2); 4,4'-dihydroxy-trans-stilbene (4,4'-DHS) (3); 4-hydroxy-trans-stilbene (4-HS) (4); 3,5-dihydroxy-trans-stilbene (3,5-DHS) (5); 3,3'-dimethoxy-4,4'-dihydroxy-trans-stilbene (3,3'-DM-4,4'-DHS) (6); 2,4-dihydroxy-trans-stilbene (2,4-DHS) (7) and 2,4,4'-trihydroxy-trans-stilbene (2,4,4'-THS) (8). It was found that all compounds studied were effective antioxidants with the exception of 3, 5-DHS. The high antioxidant activity of both 3, 3'-DM-4, 4'-DHS and 3, 4-DHS may be due to the abstraction of the two hydrogen atoms of the para and ortho-position hydroxyls respectively, to form a quinone structure. Our results revealed that the antioxidant pharmacophore of 2,4-DHS and 2,4,4'-THS, exhibiting higher antioxidant activity than resveratrol, is the 2-hydroxystilbene, rather than 4-hydroxystilbene. Experimental observations were satisfactorily explained and commented.