Interaction of bisulfite with unsaturated fatty acids.

Sodium bisulfite reacted with unsaturated fatty acids, significantly increasing their polarity as determined by behavior on silica gel thin-layer chromatography. The ultraviolet absorption spectra of unsaturated fatty acids (due to the presence of double bonds) were abolished as a result of the reaction. Fatty acids containing more than one double bond (arachidonate, linolinate, and linoleate) reacted more rapidly with bisulfite than did oleate. When arachidonate double bonds were titrated with bisulfite there was a much larger spectral decrease with the first equivalent of bisulfite added than with each subsequent addition. Vitamin E, vitamin E nicotinate, and butylated hydroxytoluene significantly inhibited the reaction of bisulfite with unsaturated fatty acids. It is suggested that the reaction of bisulfite with unsaturated fatty acids may be a mechanism of SO2 toxicity.