Free radical scavenging properties of melanin interaction of eu- and pheo-melanin models with reducing and oxidising radicals.
AffiliationDepartment of Biophysics, Institute of Molecular Biology, Jagiellonian University, Kraków, Poland.
MetadataShow full item record
AbstractThe human skin and eye melanin is commonly viewed as an efficient photoprotective agent. To elucidate the molecular mechanism of the melanin-dependent photoprotection, we studied the interaction of two synthetic melanins, dopa-melanin and cysteinyldopa-melanin, with a wide range of oxidising and reducing free radicals using the pulse radiolysis technique. We have found that although both types of free radicals could efficiently interact with the synthetic melanins, their radical scavenging properties depended, in a complex way, on the redox potential, the electric charge and the lifetime of the radicals. Repetitive pulsing experiments, in which the free radicals, probing the polymer redox sites, were generated from four different viologens, indicated that the eumelanin model had more reduced than oxidised groups accessible to reaction with the radicals. Although with many radicals studied, melanin interacted via simple one-electron transfer processes, the reaction of both melanins with the strongly oxidising peroxyl radical from carbon tetrachloride, involved radical addition. Our study suggests that the free radical scavenging properties of melanin may be important in the protection of melanotic cells against free radical damage, particularly if the reactive radicals are generated in close proximity to the pigment granules.
CitationFree radical scavenging properties of melanin interaction of eu- and pheo-melanin models with reducing and oxidising radicals. 1999, 26 (5-6):518-25 Free Radic. Biol. Med.
JournalFree Radical Biology & Medicine
- Interaction of radicals from water radiolysis with melanin.
- Authors: Sarna T, Pilas B, Land EJ, Truscott TG
- Issue date: 1986 Aug 6
- Interaction of melanin with carbon- and oxygen-centered radicals from methanol and ethanol.
- Authors: Dunford R, Land EJ, Rozanowska M, Sarna T, Truscott TG
- Issue date: 1995 Dec
- The role of melanin as protector against free radicals in skin and its role as free radical indicator in hair.
- Authors: Herrling T, Jung K, Fuchs J
- Issue date: 2008 May
- Nitroxides as redox probes of melanins: dark-induced and photoinduced changes in redox equilibria.
- Authors: Sarna T, Korytowski W, Sealy RC
- Issue date: 1985 May 15
- Time-resolved detection of melanin free radicals quenching reactive oxygen species.
- Authors: Seagle BL, Rezai KA, Gasyna EM, Kobori Y, Rezaei KA, Norris JR Jr
- Issue date: 2005 Aug 17