The influence of antioxidants in the thiyl radical induced lipid peroxidation and geometrical isomerization in micelles of linoleic acid

摘要

The biomimetic model of micelles of linoleic acid containing 2-mercaptoethanol and the antioxidant was examined under gamma irradiation up to 400 Gy in aerobic or deoxygenated conditions where thiyl radicals are the main reactive species. Lipid peroxidation was retarded by ascorbic acid and α-tocopherol, whereas this process was strongly inhibited by resveratrol as effectively as the ascorbic acid/α-tocopherol mixture. Furthermore, antioxidants have a much stronger inhibitory effect on the peroxidation in the presence of 2-mercaptoethanol, and at the same time show protective properties of the double bond, decreasing the cis–trans isomerization. Under anaerobic conditions cis–trans isomerization occurred and antioxidants efficiency increased along the series: resveratrol α-tocopherol ascorbic acid. This result is explained taking into account the double bond localization in the hydrophobic core of the micelle and the need of co- localization of the antioxidant in order to get an anti-isomerizing activity and protection of the natural lipid geometry.