Singlet Molecular Oxygen Generated from Lipid Hydroperoxides by the Russell Mechanism: Studies Using 18O-Labeled Linoleic Acid Hydroperoxide and Monomol Light Emission Measurements
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- 作者：Sayuri Miyamoto ; Glaucia R. Martinez ; Marisa H. G. Medeiros ; and Paolo Di Mascio
- 刊名：Journal of the American Chemical Society
- 出版年：2003
- 出版时间：May 21, 2003
- 年：2003
- 卷：125
- 期：20
- 页码：6172 - 6179
- 全文大小：206K
- 年卷期：v.125,no.20(May 21, 2003)
- ISSN：1520-5126
文摘
The decomposition of lipid hydroperoxides into peroxyl radicals is a potential source of singletoxygen (1O2) in biological systems. We report herein on evidence of the generation of 1O2 from lipidhydroperoxides involving a cyclic mechanism from a linear tetraoxide intermediate proposed by Russell.Using 18O-labeled linoleic acid hydroperoxide (LA18O18OH) in the presence of Ce4+ or Fe2+, we observedthe formation of 18O-labeled 1O2 (18[1O2]) by chemical trapping of 1O2 with 9,10-diphenylanthracene (DPA)and detected the corresponding 18O-labeled DPA endoperoxide (DPA18O18O) by high-performance liquidchromatography coupled to tandem mass spectrometry. Spectroscopic evidence for the generation of 1O2was obtained by measuring (i) the dimol light emission in the red spectral region (
> 570 nm); (ii) themonomol light emission in the near-infrared (IR) region ( = 1270 nm); and (iii) the quenching effect ofsodium azide. Moreover, the presence of 1O2 was unequivocally demonstrated by the direct spectralcharacterization of the near-IR light emission. For the sake of comparison, 1O2 deriving from the H2O2/OCl- and H2O2/MoO42- systems or from the thermolysis of the endoperoxide of 1,4-dimethylnaphthalenewas also monitored. These chemical trapping and photoemission properties clearly demonstrate that thedecomposition of LA18O18OH generates 18[1O2], consistent with the Russell mechanism and pointing to theinvolvement of 1O2 in lipid hydroperoxide mediated cytotoxicity.
> 570 nm); (ii) themonomol light emission in the near-infrared (IR) region ( = 1270 nm); and (iii) the quenching effect ofsodium azide. Moreover, the presence of 1O2 was unequivocally demonstrated by the direct spectralcharacterization of the near-IR light emission. For the sake of comparison, 1O2 deriving from the H2O2/OCl- and H2O2/MoO42- systems or from the thermolysis of the endoperoxide of 1,4-dimethylnaphthalenewas also monitored. These chemical trapping and photoemission properties clearly demonstrate that thedecomposition of LA18O18OH generates 18[1O2], consistent with the Russell mechanism and pointing to theinvolvement of 1O2 in lipid hydroperoxide mediated cytotoxicity.