P 060 - New radical-regulatory properties of tryptophan and its derivatives

Abstract

The effects provoked by ionizing radiation or metabolic disturbances in a living organism result in hyperproduction of reactive species, including O-, C- and N-centered organic and inorganic radicals. Further transformations of such radicals lead to activation of free-radical processes causing damage to biologically relevant molecules. Such processes account for and/or participate in the development of cardiovascular, neurodegenerative, oncological and inflammatory diseases. So, radical-regulatory activity of substances should be mainly associated with their high reactivity towards different types of organic radicals. The subject of this study was investigation of new type tryptophan and its derivatives interactions with O- and C-centered radicals being formed during radiation- and peroxide-induced transformations of organic compounds and with N-centered 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical. Tryptophan and its derivatives displayed the antioxidant properties due to the ability of these compounds to reduce O-centered organic radicals via the reaction of electron transfer from the lone pair of nitrogen atoms. We have found that substances under study can add and oxidize C-centered organic radicals. Serotonin and 5-hydroxytryptophan are characterized by moderate reactivity toward the N-centered DPPH radical as compared with that of classical antioxidants.