Formation of Superoxide Anion during Ferrous Ion-Induced Decomposition of Linoleic Acid Hydroperoxide under Aerobic Conditions

抄録

We studied the mechanism of formation of oxygen radicals during ferrous ioninduced decomposition of linoleic acid hydroperoxide using the spin trapping and chemiluminescence methods. The formation of the superoxide anion (O₂^_??_-) was verified in the present study. The hydroxyl radical is also generated through Fenton type decomposition of hydrogen peroxide produced on disproportionation of O₂^_??_-. A carbon-centered radical was detected using 5-(diethoxyphosphoryl)-5-methyl-l-pyrroline N-oxide (DEPMPO) as a spin trap. Alkoxyl radical formation is essential for the conversion of linoleic acid hydroperoxide into the peroxyl radical by ferrous ion. It is likely that the alkoxyl radical [R₁CH(O^_??_)R₂] is converted into the hydroxylcarbon radical [R₁C_??_-(OH)R₂] in water, and that this carbon radical reacts with oxygen to give the α-hydroxyperoxyl radical [R₁R₂C(OH)OO_??_], which decomposes into the carbocation [R₁C⁺(OH)R₂] and O₂^_??_-.