P 010 - UV-induced free radical transformations of sphingolipids

Abstract

Photochemical transformations of membrane lipids can lead to their modification and/or destruction, and consequently cause changes in their biological functions. Among the most studied photoinduced reactions of glycerophospholipids are the processes of lipid oxidation and oxidative degradation. Sphingolipids unlike glycerophospholipids resistant to peroxidation processes. At the same time, these lipids are part of the plasma membranes of skin cells and exposed to UV light. We have sown that direct action of UV irradiation on sphingomyelins in water dispersions induces the Norrish type I decomposition with the formation and subsequence rupture of nitrogen-centered radicals. In the case of sphingosine, containing a free amino group, its photolysis can lead to the photodissociation and formation of N-centered radicals due to n,σ * - transition. The main products of sphingolipids photodestruction were unsaturated aldehydes, which possess a wide spectrum of biological activity. The photolysis of sphingosine and sphingomyelin with the addition of sensitizers expands the range of photolysis products via the possible formation of N- and C-centered radicals. The results of this study can broaden the frontier of research regarding to the mechanisms of photochemical reactions of sphingolipids that may be involved in the development of UV-erythema of the skin, radiation damages.