Photodegradation of unsaturated fatty acids in senescent cells of phytoplankton: photoproduct structural identification and mechanistic aspects

Abstract

The light-induced degradation of unsaturated fatty acids in killed phytoplanktonic cells seems to involve mainly singlet oxygen and to a lesser extent radical oxidation. These processes afford isomeric allylic hydroperoxyacids, which are then either reduced to the corresponding hydroxyacids or cleaved to ω-oxocarboxylic acids and aldehydes (Hock cleavage). α,ω-Dicarboxylic acids are also produced by subsequent oxidation of the corresponding ω-oxocarboxylic acids. These different compounds constitute useful markers of photooxidative alterations of phytoplanktonic populations.