The inhibition of peroxyradical-induced chemiluminescence by melanins.
Model melanins synthesized from adrenochrome, DOPA and pyrocatechol quench the peroxyradical-coupled chemiluminescence initiated by electrolysis, photolysis and redox reactions in several selected systems. Calculations of the selfadsorption (inner filter effect) of melanins that decreases chemiluminescence intensity as well as changes in absorption spectra of photolabile substrate-probes such as cytochrome c and rhodamine, lead to the conclusion that melanins scavenge peroxyradicals and inhibit chemiluminescence. The inhibition effect (beta-value) is much higher than that of most powerful antioxidants in all chemiluminescence systems excluding the luminol-hydrogen peroxide one. Donor-acceptor properties of melanins, pertinent to their antioxidizing activity, are discussed.
D000975:Antioxidants / Q000494:pharmacology*; D005609:Free Radicals; D008163:Luminescent Measurements; D008543:Melanins / Q000138:chemical synthesis / Q000494:pharmacology*; D010084:Oxidation-Reduction; D010545:Peroxides / Q000378:metabolism*; D013053:Spectrophotometry; D013481:Superoxides / Q000378:metabolism
D000975:Antioxidants; D005609:Free Radicals; D008543:Melanins; D010545:Peroxides; D013481:Superoxides