Yu Qingfeng, Shan Zhen, Ni Kunyi, Qian Steven Y
Department of Pharmaceutical Sciences, College of Pharmacy, Nursing, and Allied Sciences, North Dakota State University, Fargo, ND 58105, USA.
Free Radic Res. 2008 May;42(5):442-55. doi: 10.1080/10715760802085344.
Gamma-linolenic acid (GLA) has been reported as a potential anti-cancer and anti-inflammatory agent and has received substantial attention in cancer care research. One of the many proposed mechanisms for GLA biological activity is free radical-mediated lipid peroxidation. However, no direct evidence has been obtained for the formation of GLA-derived radicals. In this study, a combination of LC/ESR and LC/MS was used with alpha-[4-pyridyl-1-oxide]-N-tert-butyl nitrone (POBN) to profile the carbon-centred radicals that are generated in lipoxygenase-catalysed GLA peroxidation. A total of four classes of GLA-derived radicals were characterized including GLA-alkyl, epoxyallylic, dihydroxyallylic radicals and a variety of carbon-centred radicals stemming from the beta-scissions of GLA-alkoxyl radicals. By means of an internal standard in LC/MS, one also quantified each radical adduct in all its redox forms, including an ESR-active form and two ESR-silent forms. The results provided a good starting point for ongoing research in defining the possible biological effects of radicals generated from GLA peroxidation.
γ-亚麻酸（GLA）已被报道为一种潜在的抗癌和抗炎剂，并在癌症护理研究中受到了广泛关注。GLA生物活性的众多潜在机制之一是自由基介导的脂质过氧化。然而，尚未获得GLA衍生自由基形成的直接证据。在本研究中，将液相色谱/电子自旋共振（LC/ESR）和液相色谱/质谱（LC/MS）联用，并使用α-[4-吡啶基-1-氧化物]-N-叔丁基硝酮（POBN）来分析在脂氧合酶催化的GLA过氧化过程中产生的碳中心自由基。共鉴定出四类GLA衍生自由基，包括GLA-烷基自由基、环氧烯丙基自由基、二羟基烯丙基自由基以及源自GLA烷氧基自由基β-断裂的各种碳中心自由基。通过LC/MS中的内标，还对每种自由基加合物的所有氧化还原形式进行了定量，包括一种ESR活性形式和两种ESR沉默形式。这些结果为正在进行的研究提供了一个良好的起点，有助于确定GLA过氧化产生的自由基可能的生物学效应。
