López-Alarcón C, Lissi E
University of Santiago, Faculty of Chemistry and Biology, Santiago, Chile.
Free Radic Res. 2006 Sep;40(9):979-85. doi: 10.1080/10715760500481233.
Oxygen radicals absorbance capacities (ORAC) indexes are frequently employed to characterize the radical trapping capacity of pure compounds and their complex mixtures. A drawback of ORAC values obtained using phycoerythrin, fluorescein (FL) or c-phycocyanin as targets, makes it possible to conclude that for very reactive compounds they are much more related to stoichiometric factors than to the reactivity of the tested compound. In the present paper, we propose a simple methodology, based on the bleaching of Pyrogallol Red (PGR) absorbance that provides ORAC indexes that are almost exclusively determined by the reactivity of the tested compounds. This difference is due to the high reactivity of PGR and the high concentrations of this compound employed in the experiments.
氧自由基吸收能力（ORAC）指数经常被用于表征纯化合物及其复杂混合物的自由基捕获能力。使用藻红蛋白、荧光素（FL）或藻蓝蛋白作为靶标获得的ORAC值存在一个缺点，这使得人们有可能得出结论，对于反应性很强的化合物，它们与化学计量因素的关系比与被测化合物的反应性的关系更大。在本文中，我们提出了一种基于邻苯三酚红（PGR）吸光度漂白的简单方法，该方法提供的ORAC指数几乎完全由被测化合物的反应性决定。这种差异是由于PGR的高反应性以及实验中使用的该化合物的高浓度。
