[Behavior of alpha-tocopherol during the autoxidation of linoleic acid in aqueous solution].
Addition of great quantity of alpha-tocopherol to an aqueous solution containing linoleic acid dispersed with twen 20 conduce to an important augmentation of the rate of formation of linoleic hydroperoxides. In these particular conditions, alpha-tocopherol have a prooxidant effect. In the same time, alpha-tocopherol is rapidly transformed into tocopherylquinone and a dimer of alpha-tocopherol. Transitorily there is formation of a dihydroxydimer of alpha-tocopherol. Comparison of these compounds behaviour on the oxydation rate of linoleic acid in the same conditions show a near relation between a prooxidant effect and chemical structure of these compounds as well as alpha-tocopherol. So, alpha-tocopherol and its dihydroxydimer are both prooxidant and both have a free hydroxyl on carbon 6. Dimer of alpha-tocopherol and tocopherylquinone are both antioxidant and they have neither free hydroxyl on carbon 6. alpha-tocopherol acetate in the same conditions have an antioxidant comportment. This confirms the importance of free hydroxyl on carbon 6 to obtain a prooxidant effect.
D000975:Antioxidants; D055598:Chemical Phenomena; D002621:Chemistry; D007700:Kinetics; D008041:Linoleic Acids; D010084:Oxidation-Reduction; D010545:Peroxides; D011809:Quinones; D013329:Structure-Activity Relationship; D014810:Vitamin E
D000975:Antioxidants; D008041:Linoleic Acids; D010545:Peroxides; D011809:Quinones; D014810:Vitamin E
Comportement de l'alpha-tocophérol au cours de l'autoxydation de l'acide linoléique en milieu aqueux.