Evaluation of resveratrol derivatives as potential antioxidants and identification of a reaction product of resveratrol and 2,2-diphenyl-1-picryhydrazyl radical

Resveratrol (3,4',5-trihydroxy-trans-stilbene), an antioxidant from grapes, and five other polyhydroxystilbenes were synthesized. Their antioxidative properties were evaluated in two model systems [pure lipid oxidation using the Rancimat method and 2,2-diphenyl-1-picryhydrazyl (DPPH) free radical scavenging model.] 3,3',4,5'-Tetrahydroxystilbene, 3,3',4,5,5'-pentahydroxystilbene, and 3,4,4',5-tetrahydroxystilbene were found to be more active than resveratrol in both models. A dimer of resveratrol was identified as the major radical reaction product when resveratrol was reacted with DPPH radicals.