Structure-activity relationship and mechanism of the tocopherol-regenerating activity of resveratrol and its analogues.
The present study investigated the mechanism of the synergistic antioxidant activity of alpha-tocopherol with resveratrol (3,5,4'-trihydroxy-trans-stilbene, 3,5,4'-THS) and its synthetic analogues, that is, 3,4-dihydroxy-trans-stilbene (3,4-DHS), 4,4'-dihydroxy-trans-stilbene (4,4'-DHS), 4-hydroxy-trans-stilbene (4-HS), and 3,5-dihydroxy-trans-stilbene (3,5-DHS). The reaction kinetics of alpha-tocopheroxyl radical with resveratrol and its analogues were studied in sodium dodecyl sulfate (SDS) and cetyl trimethylammonium bromide (CTAB) micelles using the stopped-flow electron paramagnetic resonance (EPR) technique. It was found that resveratrol and its analogues could regenerate alpha-tocopherol with rate constants (k(REG)) in the order of 3,4-DHS > 4,4'-DHS > resveratrol > or = 4-HS > or = 3,5-DHS in SDS and CTAB micelles. It was found that the analogues bearing o-dihydroxyl groups (3,4-DHS) and p-dihydroxyl groups (4,4'-HS) exhibited remarkably higher alpha-tocopherol-regenerating activity than those bearing no such groups (resveratrol, 4-HS, and 3,5-DHS). In addition, the alpha-tocopherol-regenerating activity of resveratrol and its analogues was correlated with their electrochemical behaviors, suggesting that electron transfer might play a critical role during the regeneration reaction.
Fang
Jian-Guo
JG
Lanzhou University, Gansu, China.
Zhou
Bo
B
D000975:Antioxidants / Q000737:chemistry; D007700:Kinetics; D010084:Oxidation-Reduction; D000077185:Resveratrol; D013267:Stilbenes / Q000138:chemical synthesis / Q000737:chemistry*; D013329:Structure-Activity Relationship; D024505:Tocopherols / Q000737:chemistry*
D000975:Antioxidants; D013267:Stilbenes; D000077185:Resveratrol; D024505:Tocopherols