engleski

RADICAL INDUCED MODIFICATIONS OF LINOLEIC ACID IN THE PRESENCE OF NATURAL ANTIOXIDANTS

For a long time lipid peroxidation has been a process of considerable interest because of its significant negative effects on biological systems resulted during oxidative stress. A much recent research deals with geometrical isomerization of polyunsaturated fatty acids which can occur due to radical stress. Free radical reactivity of thiol compounds is the common link between two processes, since lipid peroxidation is inhibited by thiols whereas geometrical isomerization is catalysed by S-centered radical (RS•). We have established the simplest biomimetic model of cell membrane, the micelles of linoleic acid in which we followed two processes in parallel.1, 2 Furthermore, we investigated the influence of several natural occurring antioxidants on radical induced lipid reactions. The systems were irradiated by gamma radiation up to 400 Gy under a variety of conditions where RS• are the main reactive species. The results have shown that lipid peroxidation was retarded by ascorbic acid and alpha-tocopherol, whereas this process was strongly inhibited by resveratrol. At the same time, the process of trans-isomerization was found to increase under anaerobic conditions along the series: resveratrol  -tocopherol  ascorbic acid. This study contributes to the understanding of the role of antioxidants in radical processes which are not only able to prevent peroxidation but can also behave as anti-isomerizing compounds. References: [1] B. Mihaljević, I. Tartaro, N. Filipović Vinceković, Eur. J. Lipid Sci. Technol. 114 (2012) 1292–1303. [2] B. Mihaljević, I. Tartaro, C. Ferreri, C. Chatgilialoglu, Org. Biomol. Chem. 9 (2011) 3541–3548.

antioxidants; thiyl radicals; lipid peroxidation; cis-trans isomerization

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