title: [Quenching of singlet molecular oxygen by screening pigments-- melanins and ommochromes].
abstract: Synthetic DOPA-melanin and natural screening pigments--sepiomelanin and ommochromes are shown to quench the luminescence of singlet molecular oxygen (1O2) in aqueous (D2O, pD = 7.5-8.1) solutions. The rate constants of 1O2 quenching are found to be equal to (1.2 +/- 0.6) 10(8) M-1 s-1 for monomeric units in DOPA-melanin and to (3 +/- 1) 10(6) M-1 s-1 for ommochromes. The data suggest that screening is not the only function of melanins, which may play a role of inhibitors of photodynamic damage in living tissues.
authors: S Iu
authors: SIu
authors: Egorov
authors: A E
authors: AE
authors: Dontsov
authors: A A
authors: AA
authors: Krasnovskiĭ
authors: M A
authors: MA
authors: Ostrovskiĭ
mesh_terms: D000818:Animals; D008543:Melanins / Q000494:pharmacology*; D010100:Oxygen; D010640:Phenothiazines / Q000494:pharmacology*; D010777:Photochemistry; D010860:Pigments, Biological / Q000494:pharmacology*; D026082:Singlet Oxygen
chemical_list: D008543:Melanins; D010640:Phenothiazines; D010860:Pigments, Biological; C002772:ommochrome; D026082:Singlet Oxygen; D010100:Oxygen
vernacular_title: Tushenie singletnogo molekuliarnogo kisloroda ékraniruiushchimi pigmentami--melaninami i ommokhromami.