Erben-Russ M, Bors W, Saran M
Int J Radiat Biol Relat Stud Phys Chem Med. 1987 Sep;52(3):393-412. doi: 10.1080/09553008714551871.
Linoleic acid peroxyl radicals (LOO.) can be viewed as model intermediates occurring during lipid peroxidation processes. Formation and reactions of these species were investigated in aqueous alkaline solution using the technique of pulse radiolysis combined with kinetic spectroscopy. Irradiation of linoleic acid in N2O/O2-saturated solutions leads to a mixture of peroxyl radical isomers, whereas reaction of 13-hydroperoxylinoleic acid (13-LOOH) with azide radicals in N2O-saturated solution produces 13-LOO. radicals specifically. These peroxyl radicals cannot be observed directly, but their reactions with the two flavonols, kaempferol and quercetin, acting as radical-scavenging antioxidants, produced strongly absorbing aroxyl radicals (ArO.). The same aroxyl radicals were generated by .OH and N3. with rate constants exceeding 10(9) dm3 mol-1 s-1. Applying a reaction scheme that includes competing generation and decay reactions of both LOO. and ArO. radicals, we derived individual rate constants for LOO. reactions with the phenols (greater than 10(7) dm3 mol-1 s-1), with the aroxyl radicals to form covalent adducts (greater than 10(8) dm3 mol-1 s-1), as well as for their bimilecular decay (3.0 X 10(8) dm3 mol-1 s-1). These results demonstrate the high reactivity of both fatty acid peroxyl radicals and the flavone antioxidants in aqueous solution.
亚油酸过氧自由基（LOO.）可被视为脂质过氧化过程中出现的模型中间体。利用脉冲辐解技术结合动力学光谱法，在碱性水溶液中研究了这些物种的形成和反应。在N2O/O2饱和溶液中辐照亚油酸会产生过氧自由基异构体混合物，而在N2O饱和溶液中13 - 氢过氧亚油酸（13 - LOOH）与叠氮自由基反应则会特异性地产生13 - LOO.自由基。这些过氧自由基无法直接观测到，但它们与两种黄酮醇（山奈酚和槲皮素）作为自由基清除抗氧化剂发生反应时，会产生强吸收的芳氧基自由基（ArO.）。由.OH和N3.也能产生相同的芳氧基自由基，其速率常数超过10(9) dm3 mol-1 s-1。应用一个包含LOO.和ArO.自由基竞争生成与衰变反应的反应方案，我们得出了LOO.与酚类反应（大于10(7) dm3 mol-1 s-1）、与芳氧基自由基形成共价加合物（大于10(8) dm3 mol-1 s-1）以及其二分子衰变（3.0×10(8) dm3 mol-1 s-1）的各个速率常数。这些结果证明了脂肪酸过氧自由基和黄酮类抗氧化剂在水溶液中的高反应活性。
