Date of Award

1990

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Chemistry

First Advisor

William A. Pryor

Abstract

Nitrogen Dioxide is a toxic air pollutant that exists at less than 0.5 ppm in the atmosphere. This toxic compound is known to initiate autoxidation of unsaturated fatty acids both in vivo and in vitro. When autoxidation occurs in vivo, membrane damage that can lead to cell death can occur. Low concentrations of nitrogen dioxide were shown to react with the polyunsaturated fatty acid esters, methyl linoleate and methyl linolenate, by a H-abstraction mechanism. However, methyl oleate, an unsaturated fatty acid ester, was demonstrated to react with a low concentration of nitrogen dioxide by only an addition mechanism. Although methyl oleate reacts by an addition mechanism, a 50:50 molar solution of methyl oleate and methyl linoleate reacted with a low level of nitrogen dioxide exclusively by a H-abstraction mechanism. Therefore, low levels of nitrogen dioxide will probably react with polyunsaturated fatty acid components of pulmonary lipids by a H-abstraction mechanism forming nitrous acid directly in the cell membrane. Vitamin E was demonstrated to be able to act as a preventative antioxidant in the nitrogen dioxide and methyl linoleate reactions; but vitamin C could not prevent nitrogen dioxide from reacting with methyl linoleate by a H-abstraction mechanism. These results suggest that low levels of nitrogen dioxide will react with polyunsaturated fatty acids by a H-abstraction mechanism and that vitamin E can be used to prevent the reaction from occurring.

Pages

216

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