Department of Chemical Ecology and Ecosystem Research, University of Vienna, Vienna, Austria.
Redox Rep. 2011;16(6):242-7. doi: 10.1179/1351000211Y.0000000015.
Flavonoids are ubiquitous phenolic plant metabolites. Many of them are well known for their pro- and antioxidant properties. Myricetin has been reported to be either a potent antioxidant or a pro-oxidant depending on the conditions. The reaction conditions for the pro- and antioxidant activities were therefore investigated using variations of the deoxyribose degradation assay systems.
The deoxyribose degradation assay systems were conducted as follows; H(2)O(2)/Fe(III)/ascorbic acid, H(2)O(2)/Fe(III), Fe(III)/ascorbic acid, and Fe(III). Each system was carried out in two variants, FeCl(3) (iron ions added as FeCl(3)) and FeEDTA (iron added in complex with ethylenediaminetetraacetic acid).
When ascorbic acid was present, myricetin showed antioxidant properties, especially when it occurred in complex with iron. In ascorbic acid-free systems, pro-oxidant activities prevailed, which where enhanced if iron was in complex with EDTA.
Myricetin's antioxidant activity depends on both the reactive oxygen species (ROS) scavenging and iron ions chelation properties. The pro-oxidative properties are caused by reduction of molecular oxygen to ROS and iron(III) to iron(II). Myricetin is able to substitute for ascorbic acid albeit less efficiently.
类黄酮是普遍存在的植物酚类代谢物。它们中的许多物质因其具有抗氧化和促氧化特性而闻名。据报道，杨梅素的抗氧化和促氧化特性取决于条件。因此，使用脱氧核糖降解测定系统的变化来研究其抗氧化和促氧化活性的反应条件。
脱氧核糖降解测定系统如下进行；H（2）O（2）/Fe（III）/抗坏血酸、H（2）O（2）/Fe（III）、Fe（III）/抗坏血酸和 Fe（III）。每个系统都有两种变体，FeCl（3）（铁离子以 FeCl（3）的形式添加）和 FeEDTA（铁与乙二胺四乙酸形成复合物添加）。
当抗坏血酸存在时，杨梅素表现出抗氧化特性，尤其是与铁形成复合物时。在没有抗坏血酸的系统中，促氧化活性占主导地位，如果铁与 EDTA 形成复合物，则会增强。
杨梅素的抗氧化活性取决于活性氧（ROS）清除和铁离子螯合特性。促氧化特性是由分子氧还原为 ROS 和铁（III）还原为铁（II）引起的。杨梅素能够替代抗坏血酸，尽管效率较低。
