TEAC antioxidant activity of 4-hydroxybenzoates.
TEAC antioxidant activity of 4-hydroxybenzoates.
复制标题
4-羟基苯甲酸酯的 TEAC 抗氧化活性。
DOI：
10.1016/s0891-5849(99)00192-6
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发表时间：
1999
影响因子：
7.4
通讯作者：
I. Rietjens
中科院分区：
文献类型：
--
作者：
B. Tyrakowska;A. Soffers;H. Szymusiak;S. Boeren;M. Boersma;K. Lemańska;J. Vervoort;I. Rietjens
通过实验和计算机计算，研究了pH值、内禀供电子能力和内禀供氢能力对羟基和氟取代的4-羟基苯甲酸酯类化合物抗氧化能力的影响。TEAC测定中化合物的pH依赖性行为揭示了4-羟基苯甲酸酯的非解离单阴离子形式和去质子化双阴离子形式的不同抗氧化行为。在去质子化后，4-羟基苯甲酸酯的自由基清除能力显著增加。为了进行机理比较，合成了一系列氟苯甲酸酯并将其包括在研究中。氟取代基对4-羟基苯甲酸酯的质子和给电子能力的影响与羟基取代基相同。氟取代基对4-羟基苯甲酸酯的TEAC值和供氢能力的影响与羟基取代基不同。这些实验数据的计算机计算的特性的比较表明，单阴离子形式的4-羟基苯甲酸酯的抗氧化剂的行为不是由分子的倾向，捐赠一个电子，但由它的能力，捐赠一个氢原子。总之，这些结果定性和定量地解释了羟基基团的数量和位置如何影响4-羟基苯甲酸酯的抗氧化行为。
The influence of pH, intrinsic electron donating capacity, and intrinsic hydrogen atom donating capacity on the antioxidant potential of series of hydroxy and fluorine substituted 4-hydroxybenzoates was investigated experimentally and also on the basis of computer calculations. The pH-dependent behavior of the compounds in the TEAC assay revealed different antioxidant behavior of the nondissociated monoanionic form and the deprotonated dianionic form of the 4-hydroxybenzoates. Upon deprotonation the radical scavenging ability of the 4-hydroxybenzoates increases significantly. For mechanistic comparison a series of fluorobenzoates was synthesized and included in the studies. The fluorine substituents were shown to affect the proton and electron donating abilities of 4-hydroxybenzoate in the same way as hydroxyl substituents. In contrast, the fluorine substituents influenced the TEAC value and the hydrogen atom donating capacity of 4-hydroxybenzoate in a way different from the hydroxyl moieties. Comparison of these experimental data to computer-calculated characteristics indicates that the antioxidant behavior of the monoanionic forms of the 4-hydroxybenzoates is not determined by the tendency of the molecule to donate an electron, but by its ability to donate a hydrogen atom. Altogether, the results explain qualitatively and quantitatively how the number and position of OH moieties affect the antioxidant behavior of 4-hydroxybenzoates.
影响因子：
4.1
作者：
Liebler, DC;McClure, TD
通讯作者：
McClure, TD