Rice-Evans C A, Miller N J, Bolwell P G, Bramley P M, Pridham J B
Free Radical Research Group, UMDS-Guy's Hospital, London.
Free Radic Res. 1995 Apr;22(4):375-83. doi: 10.3109/10715769509145649.
The relative antioxidant activities, against radicals generated in the aqueous phase, of a range of plant-derived polyphenolic flavonoids, constituents of fruit, vegetables, tea and wine, have been assessed. The results show that compounds such as quercetin and cyanidin, with 3',4' dihydroxy substituents in the B ring and conjugation between the A and B rings, have antioxidant potentials four times that of Trolox, the vitamin E analogue. Removing the ortho-dihydroxy substitution, as in kaempferol, or the potential for electron delocalisation by reducing the 2,3 double bond in the C ring, as in catechin and epicatechin, decreases the antioxidant activity by more than 50%, but these structures are still more effective than alpha-tocopherol or ascorbate. The relative significance of the positions and extents of hydroxylation of the A and B rings to the total antioxidant activity of these plant polyphenolics is demonstrated.
对一系列植物来源的多酚类黄酮（水果、蔬菜、茶和葡萄酒的成分）针对水相中产生的自由基的相对抗氧化活性进行了评估。结果表明，诸如槲皮素和花青素等化合物，其B环具有3',4' -二羟基取代基且A环和B环之间存在共轭，其抗氧化潜力是维生素E类似物Trolox的四倍。去除邻二羟基取代，如在山奈酚中，或通过减少C环中的2,3双键来消除电子离域的可能性，如在儿茶素和表儿茶素中，会使抗氧化活性降低超过50%，但这些结构仍然比α-生育酚或抗坏血酸更有效。A环和B环羟基化的位置和程度对这些植物多酚类物质总抗氧化活性的相对重要性得到了证明。
