Studies of radiation induced peroxidation in fatty acid micelles

Studies of irradiation induced lipid peroxidation in fatty acid micelles, both from our own lab and others, are briefly summarized. Steady state measurements have shown the dependence of hydroperoxide yield on the state of aggregation in the lipid and the degree to which the reactive sites are close packed. Chromatographic measurements obeyed the square root dependence of yield on dose rate confirming the proposed chain mechanism. Application to antioxidant studies have demonstrated the highly efficient blockage of the peroxidation chain by α-tocopherol and the subsequent prooxidant effect of the product formed. Time resolved studies have been used to determine rate information for .OH-lipid interaction, radical transfer within the lipid, radical peroxidation, lipid radical movement across the micellar boundary, chain termination, and radical interaction with α-tocopherol. Complimentary laser studies have demonstrated, in contrast to .OH behavior, the comparatively high degree of selectively exhibited by alkoxy radicals toward allylic lipid sites