The contribution of flavonoid C-ring on the DPPH free radical scavenging efficiency.: A kinetic approach for the 3′,4′-hydroxy substituted members
The contribution of flavonoid C-ring on the DPPH free radical scavenging efficiency.: A kinetic approach for the 3′,4′-hydroxy substituted members
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DOI：
10.1016/j.ifset.2005.09.001
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发表时间：
2006-06-01
影响因子：
6.6
通讯作者：
Oreopoulou, Vassiliki
中科院分区：
文献类型：
--
作者：
Tsimogiannis, Dimitrios I.;Oreopoulou, Vassiliki
5，7，3 '，4'-羟基取代的类黄酮被认为是非常有效的自由基清除剂。本研究考察了C环的结构元素对这些化合物的自由基清除活性的影响。研究了A环或B环的双羟基取代对全取代C环黄酮活性的影响。槲皮素，毛地黄黄酮，紫杉叶素，圣草酚，芦丁，（+）-儿茶素，（-）-表儿茶素，非瑟酮和山奈酚进行了研究，在与DPPH自由基的反应过程中，他们揭示了两个独特的反应步骤，第一个快速和第二个较慢。DPPH清除在快速步骤中遵循二级动力学;测定了化学计量因子和速率常数。槲皮素和非瑟酮每个分子清除4个自由基，而其他黄酮类化合物清除2个自由基，从而产生B-环二醌。C环结构对反应速率常数也有影响。慢步骤的动力学更为复杂，C环的贡献是基于化学计量的。(c)2005爱思唯尔有限公司保留所有权利。
5,7,3',4'-hydroxy-substituted flavonoids are considered as very efficient radical scavengers. This study examines the effect of the structural elements of the C-ring, on the radical scavenging activity of these compounds. The impact of di-hydroxy substitution of A- or B-ring on the activity of fully substituted C-ring flavonoids was also studied. Quercetin, luteolin, taxifolin, eriodictyol, rutin, (+)-catechin, (-)-epicatechin, fisetin and kaempferol were studied during the reaction with the DPPH radical; they revealed two distinctive steps of reaction, a first rapid and a second slower. DPPH scavenging followed second order kinetics during the rapid step; stoichiometric factors and rate constants were determined. Quercetin and fisetin scavenged four radicals by each molecule, while the other flavonoids scavenged two radicals with a consequent production of B-ring diquinone. Also the rate constants were affected by C-ring structure. The kinetics of the slow step was much more complicated and the contribution of C-ring was based on stoichiometry. (c) 2005 Elsevier Ltd. All rights reserved.