Photoreduction of the fluorescent dye 2'-7'-dichlorofluorescein: a spin trapping and direct electron spin resonance study with implications for oxidative stress measurements.
Free Radic Biol Med
; 26(1-2): 148-61, 1999 Jan.
Article
em En
| MEDLINE
| ID: mdl-9890650
ABSTRACT
The photoreduction of 2'-7'-dichlorofluorescein (DCF) was investigated in buffer solution using direct electron spin resonance (ESR) and the ESR spin-trapping technique. Anaerobic studies of the reaction of DCF in the presence of reducing agents demonstrated that during visible irradiation (lambda > 300 nm) 2'-7'-dichlorofluorescein undergoes one-electron reduction to produce a semiquinone-type free radical as demonstrated by direct ESR. Spin-trapping studies of incubations containing DCF, 5,5-dimethyl-1-pyrroline N-oxide (DMPO) and either reduced glutathione (GSH) or reduced NADH demonstrate, under irradiation with visible light, the production of the superoxide dismutase-sensitive DMPO/*OOH adduct. In the absence of DMPO, measurements with a Clark-type oxygen electrode show that molecular oxygen is consumed in a light-dependent process. The semiquinone radical of DCF, when formed in an aerobic system, is immediately oxidized by oxygen, which regenerates the dye and forms superoxide.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Fluoresceínas
/
Corantes Fluorescentes
Idioma:
En
Revista:
Free Radic Biol Med
Assunto da revista:
BIOQUIMICA
/
MEDICINA
Ano de publicação:
1999
Tipo de documento:
Article
País de afiliação:
Itália