Taking advantage of Light Up Cell System (LUCS) technology, which allows for fine monitoring of reactive oxygen species (ROS) production inside live cells, a new assay called Anti Oxidant Power 1 (AOP1) was developed to specifically measure ROS and/or free-radical scavenging effects inside living cells. This method is quantitative and EC₅₀s obtained from AOP1 dose-response experiments were determined in order to classify the intracellular antioxidant efficacy of 15 well known antioxidant compounds with different hydrophilic properties. Six of them (epigallocatechin gallate, quercetin, butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), ethoxyquin, resveratrol) gave EC₅₀s in the range of 7–64 μM, four (Trolox, catechin, epicatechin, EUK134) in the range of 0.14 to 1 mM, and 5 (sulforaphane, astaxanthin, α- and γ-tocopherols, vitamin E acetate) showed only partial or no effect. Interestingly, effects with measurable EC₅₀s were observed for compounds with hydrophilic properties (LogP ≤ 5.3), while all antioxidants known to act at the plasma membrane level (LogP ≥ 10.3) had partial or no effect. Sulforaphane, a hydrophilic but strict Keap1/Nrf2 pathway enhancer, did not show any effect either. Importantly, AOP1 assay captures both antioxidant and prooxidant effects. Taken together, these results led us to the conclusion that AOP1 assay measures antioxidant effect of compounds that selectively enter the cell, and act as free radical scavengers in the cytosol and/or nucleus level.

中文翻译：

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AOP1，一种直接定量检测细胞内抗氧化作用的新活细胞分析方法。

利用轻型细胞系统（LUCS）技术，该技术可以精确监控活细胞内部的活性氧（ROS）产生，开发了一种名为“抗氧化剂功率1（AOP1）”的新测定法，专门用于测量ROS和/或游离氧-活细胞内部的自由基清除作用。该方法是定量的，测定从AOP1剂量反应实验获得的EC ₅₀，以对15种具有不同亲水特性的众所周知的抗氧化剂化合物的细胞内抗氧化剂功效进行分类。其中六种（表没食子儿茶素没食子酸酯，槲皮素，丁基羟基茴香醚（BHA），丁基羟基甲苯（BHT），乙氧基喹，白藜芦醇）得到EC ₅₀s在7-64μM的范围内，四个（Trolox，儿茶素，表儿茶素，EUK134）在0.14至1 mM的范围内，而5个（萝卜硫素，虾青素，α-和γ-生育酚，维生素E醋酸盐）仅显示部分或没有效果。有趣的是，对于具有亲水特性（LogP≤5.3）的化合物，可观察到EC ₅₀ s的影响，而所有已知在质膜水平（LogP≥10.3）起作用的抗氧化剂均具有部分或完全没有作用。萝卜硫素是一种亲水但严格的Keap1 / Nrf2途径增强剂，也未显示任何作用。重要的是，AOP1分析同时捕获了抗氧化剂和促氧化剂。综上所述，这些结果使我们得出以下结论：AOP1测定可测量选择性进入细胞并在细胞质和/或细胞核水平上充当自由基清除剂的化合物的抗氧化作用。