Products and mechanism of the reaction of ozone with phospholipids in unilamellar phospholipid vesicles

Journal Article · Wed Jan 01 04:00:00 EST 1992 · Chemical Research in Toxicology; (United States)

DOI:https://doi.org/10.1021/tx00025a023· OSTI ID:5196395

Santrock, J; Gorski, R A; O'Gara, J F ^[1]

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1. Biomedical Science Department, General Motors Research Laboratories, Warren, MI (United States)

While considerable effort has been expended on determining the health effects of exposure to typical urban concentrations of O3, little is known about the chemical events responsible for toxicity. Phospholipids containing unsaturated fatty acids in the cell membranes of lung cells are likely reaction sites for inhaled ozone (O3). In this study, we examined the reaction of O3 with 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) in unilamellar phospholipid vesicles. Reaction of ozone with the carbon-carbon double bond of POPC yielded an aldehyde and a hydroxy hydroperoxide. The hydroxy hydroperoxide eliminated H2O2 to yield a second aldehyde. Upon further ozonolysis, the aldehydes were oxidized to the corresponding carboxylic acids. A material balance showed that no other reaction consumed POPC and O3 or produced these products. As a mechanistic probe, we measured incorporation of oxygen-18 from 18O3 into aldehyde, carboxylic acid, and H2O2. Approximately 50% of the aldehyde oxygen atoms were derived from O3. Oxygen in H2O2 was derived solely from O3, where both oxygen atoms in a molecule of H2O2 were from the same molecule of O3. One of the carboxylic acid oxygen atoms was derived from the precursor aldehyde, while the other was derived from O3. These results support the following mechanism. Cleavage of the carbon-carbon double bond of POPC by O3 yields a carbonyl oxide and an aldehyde. Reaction of H2O with the carbonyl oxide yields a hydroxy hydroperoxide, preventing formation ozonide by reaction of the carbonyl oxide and aldehyde. Elimination of H2O2 from the hydroxy hydroperoxide yields a second aldehyde. Oxidation of the aldehydes by O3 yields carboxylic acids.

• OSTI ID: 5196395
• Journal Information: Chemical Research in Toxicology; (United States), Journal Name: Chemical Research in Toxicology; (United States) Vol. 5:1; ISSN CRTOE; ISSN 0893-228X
• Country of Publication: United States
• Language: English

Related Subjects

560300* -- Chemicals Metabolism & Toxicology
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ALDEHYDES
BODY
CARBOXYLIC ACIDS
CELL CONSTITUENTS
CELL MEMBRANES
CHROMATOGRAPHY
ESTERS
EVEN-EVEN NUCLEI
HYDROGEN COMPOUNDS
HYDROGEN PEROXIDE
INHALATION
INTAKE
ISOTOPE APPLICATIONS
ISOTOPES
LIGHT NUCLEI
LIPIDS
LIQUID COLUMN CHROMATOGRAPHY
LUNGS
MAGNETIC RESONANCE
MASS SPECTROSCOPY
MEMBRANES
METABOLISM
NUCLEAR MAGNETIC RESONANCE
NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
ORGANS
OXYGEN 18
OXYGEN COMPOUNDS
OXYGEN ISOTOPES
OZONE
PEROXIDES
PHOSPHOLIPIDS
RESONANCE
RESPIRATORY SYSTEM
SEPARATION PROCESSES
SPECTROSCOPY
STABLE ISOTOPES
TOXICITY
TRACER TECHNIQUES