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Interactions of plasmalogens and their diacyl analogs with singlet oxygen in selected model systems.
- Source :
-
Free radical biology & medicine [Free Radic Biol Med] 2011 Apr 01; Vol. 50 (7), pp. 892-8. Date of Electronic Publication: 2011 Jan 12. - Publication Year :
- 2011
-
Abstract
- Plasmalogens are phospholipids containing a vinyl-ether linkage at the sn-1 position of the glycerophospholipid backbone. Despite being quite abundant in humans, the biological role of plasmalogens remains speculative. It has been postulated that plasmalogens are physiological antioxidants with the vinyl-ether functionality serving as a sacrificial trap for free radicals and singlet oxygen. However, no quantitative data on the efficiency of plasmalogens at scavenging these reactive species are available. In this study, rate constants of quenching of singlet oxygen, generated by photosensitized energy transfer, by several plasmalogens and, for comparison, by their diacyl analogs were determined by time-resolved detection of phosphorescence at 1270nm. Relative rates of the interactions of singlet oxygen with plasmalogens and other lipids, in solution and in liposomal membranes, were measured by electron paramagnetic resonance oximetry and product analysis using HPLC-EC detection of cholesterol hydroperoxides and iodometric assay of lipid hydroperoxides. The results show that singlet oxygen interacts with plasmalogens significantly faster than with the other lipids, with the corresponding rate constants being 1 to 2 orders of magnitude greater. The quenching of singlet oxygen by plasmalogens is mostly reactive in nature and results from its preferential interaction with the vinyl-ether bond. The data suggest that plasmalogens could protect unsaturated membrane lipids against oxidation induced by singlet oxygen, providing that the oxidation products are not excessively cytotoxic.<br /> (Copyright © 2011 Elsevier Inc. All rights reserved.)
- Subjects :
- Acylation
Antioxidants chemistry
Antioxidants metabolism
Cholesterol analogs & derivatives
Cholesterol analysis
Chromatography, High Pressure Liquid
Electron Spin Resonance Spectroscopy
Humans
Kinetics
Liposomes chemistry
Liposomes metabolism
Luminescent Measurements
Models, Chemical
Oxidation-Reduction
Vinyl Compounds chemistry
Plasmalogens chemistry
Plasmalogens metabolism
Singlet Oxygen metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 1873-4596
- Volume :
- 50
- Issue :
- 7
- Database :
- MEDLINE
- Journal :
- Free radical biology & medicine
- Publication Type :
- Academic Journal
- Accession number :
- 21236336
- Full Text :
- https://doi.org/10.1016/j.freeradbiomed.2011.01.002