This report explores the antioxidant interaction of combinations of flavonoid–glutathione with different ratios. Two different 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid radical (ABTS^•+)-based approaches were applied for the elucidation of the antioxidant capacity of the combinations. Despite using the same radical, the two approaches employ different free radical inflow systems: An instant, great excess of radicals in the end-point decolorization assay, and a steady inflow of radicals in the lag-time assay. As expected, the flavonoid–glutathione pairs showed contrasting results in these two approaches. All the examined combinations showed additive or light subadditive antioxidant capacity effects in the decolorization assay. This effect showed slight dilution dependence and did not change when the initial ABTS^•+ concentration was two times as high or low. However, in the lag-time assay, different types of interaction were detected, from subadditivity to considerable synergy. Taxifolin–glutathione combinations demonstrated the greatest synergy, at up to 112%; quercetin and rutin, in combination with glutathione, revealed moderate synergy in the 30–70% range; while morin–glutathione appeared to be additive or subadditive. In general, this study demonstrated that, on the one hand, the effect of flavonoid–glutathione combinations depends both on the flavonoid structure and molar ratio; on the other hand, the manifestation of the synergy of the combination strongly depends on the mode of inflow of the free radicals.

中文翻译：

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具有谷胱甘肽抗氧化剂协同作用的类黄酮：自由基流入的影响。

本报告探讨了不同比例的类黄酮-谷胱甘肽的抗氧化作用。两个不同的2,2'-叠氮基双（3-乙基苯并噻唑啉-6-磺酸基（ABTS ^•+基于）的方法用于阐明组合的抗氧化能力。尽管使用相同的自由基，但这两种方法使用不同的自由基流入系统：在终点脱色测定中瞬间大量过量的自由基，在滞后时间测定中稳定地流入自由基。不出所料，这两种方法中的类黄酮-谷胱甘肽对显示出相反的结果。在脱色试验中，所有检查的组合均显示出加性或轻度亚加性抗氧化能力的影响。此效应显示出轻微的稀释依赖性，并且在初始ABTS ^•+时没有变化浓度是高或低的两倍。但是，在滞后时间分析中，检测到了不同类型的相互作用，从亚可加性到可观的协同作用。紫杉醇与谷胱甘肽的组合显示出最大的协同作用，最高可达112％。槲皮素和芦丁与谷胱甘肽联用，在30-70％的范围内显示出中等协同作用；而morin-谷胱甘肽似乎是加成或亚加成的。总的来说，这项研究表明，一方面，类黄酮-谷胱甘肽组合的作用取决于类黄酮的结构和摩尔比。另一方面，组合协同作用的表现在很大程度上取决于自由基的流入方式。