HYDROXYL RADICAL FORMATION FROM CU(II)-TROLOX MIXTURES - INSIGHTS INTO THE PROOXIDANT PROPERTIES OF ALPHA-TOCOPHEROL

Although widely recognised as the most important chain-breaking antiox idant of the lipid phase, alpha-tocopherol has also been reported to e xert pro-oxidant activity, particularly during the Cu(II)-stimulated o xidation of low density lipoproteins (LDL), In the present communicati on, we demonstrate that hydroxyl radicals are generated following the interaction of Cu(II) with the alpha-tocopherol model compound Trolox, involving the reduction of Cu(II) by Trolox and the subsequent reduct ion of molecular oxygen by Cu(I). We suggest, therefore, that the hydr oxyl radical may be the species responsible for the initiation of fatt y acid oxidation during the Cu(II)-stimulated oxidation of hydroperoxi de-free LDL.