Introduction Vitamin E homologues, including α-, β-, γ-, δ-tocopherols-TocHs and tocotrienols-Toc-3Hs , are well known as the most important lipophilic antioxidants AOHs 1 3. Vitamin E homologues function as efficient inhibitors of lipid peroxidation in both foods and biological systems 1 5. The antioxidant action of TocHs and Toc-3Hs has been ascribed to their ability to scavenge lipid peroxyl LOO radicals, producing the tocopheroxyl Toc and tocotrienoxyl Toc-3 radicals, respectively reaction 1 1, 2, 6. However, if TocHs and Toc-3Hs exist in edible oils and bio-membranes, Toc and Toc-3 radicals may react with unsaturated lipids LHs reaction 2 , causing a prooxidant reaction which induces the degradation of these unsaturated lipids 5, 7 11 .