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[Melanin: structure, biosynthesis, biological functions].

Melanins are the group of natural black pigments. The structure of melanin macromolecules is irregular network arising from phenolic precursors in consequence of enzymatic and autooxidation. Melanin is stable polyradical, contain some semiquinone radicals and accumulate the exogene radicals and other active oxygen species, heavy metals, electrophyl toxic compounds. Some this properties determine the antioxidant, antitoxic, antiradiation and antitumour activity of melanins. On the base of natural melanins is possible creation of some effective prophylactic and curative preparations.