Polyunsaturated

Peroxidation

Polyunsaturated fatty acids are susceptible to lipid peroxidation, far more so than monounsaturated or saturated analogues. The basis for this reactivity is the weakness of doubly allylic C-H bonds. They are drying oils, i.e. film-forming liquids suitable as painting. One practical consequence is that polyunsaturated fatty acids have poor shelf life, owing to their tendency toward autoxidation, leading, in the case of edibles, to rancidification. Metals accelerate the degradation. A range of reactions with oxygen occur. Products include fatty acid hydroperoxides, epoxy-hydroxy polyunsaturated fatty acids, jasmonates, divinylether fatty acids, and leaf aldehydes. Some of these derivatives are signalling molecules, some are used in plant defense (antifeedants), some are precursors to other metabolites that are used by the plant.