title: Spectroscopic studies of cutaneous photosensitizing agents--XVI. Disperse blue 35.
abstract: The photochemistry (Type I and II) of the phototoxic textile dye Disperse Blue (DB-35) and its purified components has been studied using electron spin resonance in conjunction with spin trapping technique and the direct detection of singlet oxygen (1O2) luminescence. The main components of DB-35 (which is synthesized by the successive nitration, reduction and methylation of 1,8-dihydroxy-anthraquinone) were separated by HPLC and identified by mass spectrometry and 2-D NMR as 4,5-diamino-1,8-dihydroxyanthraquinone (4,5-DDHAQ; 62% of total dye) and 2,7-diamino-1,8-dihydroxyanthraquinone (2,7-DDHAQ; 31% of total dye). Minor components included 2,5-diamino-1,8-dihydroxyanthraquinone (2,5-DDHAQ) and a monomethylated derivative of either 4,5-DDHAQ or 2,7-DDHAQ. Irradiation (624 nm) of 4,5-DDHAQ and 2,7-DDHAQ in dimethylsulfoxide resulted in the generation of superoxide which was trapped by 5,5-dimethyl-1-pyrroline-N-oxide (DMPO). Visible light irradiation of the components in ethanol generated 1O2 with the yields decreasing in the following order: 4,5-DDHAQ greater than 2,5-DDHAQ greater than 2,7-DDHAQ. These findings indicate that upon irradiation by visible light DB-35 can generate active oxygen species which may be responsible for the photocontact dermatitis caused by this dye.
authors.affiliation: Laboratory of Molecular Biophysics, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709.
authors.forename: R
authors.initials: R
authors.lastname: Dabestani
authors.forename: K J
authors.initials: KJ
authors.lastname: Reszka
authors.forename: D G
authors.initials: DG
authors.lastname: Davis
authors.forename: R H
authors.initials: RH
authors.lastname: Sik
authors.forename: C F
authors.initials: CF
authors.lastname: Chignell
mesh_terms: D000880:Anthraquinones / Q000737:chemistry* / Q000494:pharmacology; D002851:Chromatography, High Pressure Liquid; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods; D006801:Humans; D013058:Mass Spectrometry; D011838:Radiation-Sensitizing Agents / Q000737:chemistry*; D012867:Skin / Q000187:drug effects
chemical_list: D000880:Anthraquinones; D011838:Radiation-Sensitizing Agents; C071486:disperse blue 35