Fluorescence formation and heme degradation at different stages of lipid peroxidation.

Secondary oxidative products of autoxidized methyl linoleate were divided into three groups (SP-I, SP-II and SP-III), which were then compared as to their abilities to form fluorescent substances and to degrade heme. SP-III showed a marked ability to produce two fluorescent substances exhibiting an excitation maximum at 350-360 nm and an emission maximum at 410-430 nm, while SP-I showed a more strongly degradative effect on heme than SP-III. The heme degradation was observed in parallel with the changes of TBA value in an early stage of lipid peroxidation and the fluorescence formation markedly increased according to the decrease of TBA value in a later stage. The results suggested that there are different reactive substances which bring about fluorescence formation and heme degradation and that they are produced at different stages of lipid peroxidation.