MaCSE Group, Sciences Chimiques de Rennes, CNRS, UMR No. 6226, ENSCR, Université de Rennes 1, Avenue du Général Leclerc, 35042 Rennes Cedex, France.
Anal Chem. 2010 Oct 15;82(20):8703-10. doi: 10.1021/ac101854w.
The reactivities of different phenols and polyphenols versus superoxide ion (O₂(•-)) were investigated as an easy-to-handle electrochemical method for evaluating antioxidant capacities. In view of this application, the O₂/O₂(•-) couple and associated reactions between O₂(•-) and polyphenols (or phenols) were examined in an aprotic solvent [dimethylformamide (DMF)] by cyclic voltammetry. Comparisons based on simple criteria (reversibility of the O₂ reduction in the presence of the phenolic compound, electron stoichiometry, or apparent kinetic constants) allow discriminations between the possible mechanistic pathways (acid-base or radical reaction type). The results highlight that the proton-transfer and radical-transfer pathways are both present for monophenols and polyphenols, with the relative contributions of the two pathways depending on the phenol structure. In agreement with the literature, polyphenols containing an o-diphenol ring (as in flavonoids) were found to present the highest reactivities.
不同酚类和多酚类物质与超氧阴离子（O₂(•-))的反应活性，被研究作为一种易于处理的电化学方法，用于评估抗氧化能力。鉴于这种应用，通过循环伏安法，在非质子溶剂[二甲基甲酰胺（DMF）]中检查了 O₂/O₂(•-)偶联和 O₂(•-)与多酚（或酚类）之间的相关反应。基于简单标准（在酚类化合物存在下 O₂还原的可逆性、电子计量关系或表观动力学常数）的比较，可以区分可能的反应途径（酸碱或自由基反应类型）。结果表明，单酚类和多酚类物质中都存在质子转移和自由基转移途径，两种途径的相对贡献取决于酚类结构。与文献一致，含有邻二酚环（如类黄酮）的多酚类物质被发现具有最高的反应活性。
