α ‐Tocopherol prooxidant effect and malondialdehyde production

α ‐Tocopherol at high concentration (1.25×10 −4 M) exhibited a prooxidant effect during autoxidation of linolenic and arachidonic acids. This prooxidant activity involved a significant increase of the conjugated diene level, especially with linolenic acid. High performance liquid chromatographic evaluation of malondialdehyde, a by‐product of the hydroperoxides of polyunsaturated fatty acids, showed that malondialdehyde was not increased during prooxidant effect of α ‐tocopherol. Thus, malondialdehyde does not seem to be a good indicator for the manifestation of the prooxidant activity of α ‐tocopherol.