Evaluation of the accuracy of antioxidant competition assays: incorrect assumptions with major impact
Evaluation of the accuracy of antioxidant competition assays: incorrect assumptions with major impact
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DOI：
10.1016/j.freeradbiomed.2009.04.009
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发表时间：
2009-07-15
影响因子：
7.4
通讯作者：
Haenen, Guido R. M. M.
中科院分区：
文献类型：
--
作者：
Balk, Jiska M.;Bast, Aalt;Haenen, Guido R. M. M.
抗氧化剂的活性通常在竞争测定中测定。在这些测定中，抗氧化剂（A）和检测分子（D）竞争反应性物质（R）。A对D与R反应的竞争性抑制作用是A抗氧化活性的量度。在测定A的活性时，通常错误地假定A和D的浓度保持等于初始浓度。然而，该测定的原理是消耗一些A和D，因此在竞争测定期间A和D的浓度将降低，导致观察到的抗氧化活性的偏差。使用计算机建模获得图形工具，以估计由A和D浓度不降低的错误假设引起的偏差程度。使用该图形工具对几种竞争测定进行了评价，表明经常报告不准确的抗氧化活性。总的来说，抗氧化剂之间的差异被低估了，所有抗氧化剂的活性都向D的抗氧化活性转移。提供了一种提高竞争测定准确度的策略。为了在竞争测定中获得准确的结果，检测分子与反应性物质的反应速率常数应与抗氧化剂的反应速率常数相当。此外，反应性物质的浓度应尽可能低。(C)2009爱思唯尔公司All rights reserved.
The activity of antioxidants is frequently determined in competition assays. In these assays an antioxidant (A) and a detector molecule (D) compete for the reactive species (R). The competitive inhibitory effect of A on the reaction of D with R is a measure of the antioxidant activity of A. In determining the activity of A, it is in general incorrectly assumed that the concentrations of A and D remain equal to the initial concentration. However, the principle of the assay is that some A and D is consumed and consequently the concentrations of A and D will decrease during a competition assay, resulting in a deviation in the observed antioxidant activity. Computer modeling was used to obtain a graphical tool to estimate the extent of the deviation caused by the incorrect assumption that the concentrations of A and D do not decrease. Several competition assays were evaluated using this graphical tool, demonstrating that frequently inaccurate antioxidant activities have been reported. In general, differences between antioxidants are underestimated and the activity of all antioxidants shifts toward the antioxidant activity of D. A strategy is provided to improve the accuracy of a competition assay. To obtain accurate results in a competition assay, the reaction rate constant of the detector molecule with the reactive species should be comparable to that of the antioxidant. In addition, the concentration of the reactive species should be as low as possible. (C) 2009 Elsevier Inc. All rights reserved.