title: Phototoxicity of some bromine-substituted rhodamine dyes: synthesis, photophysical properties and application as photosensitizers.
abstract: The synthesis of some bromine-substituted rhodamine derivatives viz., 4,5-dibromorhodamine methyl ester (dye 2) and 4,5-dibromorhodamine n-butyl ester (dye 3) are reported. These dyes were synthesized to promote a more efficient cancer cell photosensitizer for potential use in in vitro bone marrow purging in preparation for autologous bone marrow transplantation. Spectroscopic and photophysical characterization of these dyes together with rhodamine 123 (dye 1) are reported in water, methanol, ethanol and also in a microheterogeneous system, sodium dodecyl sulfate. The possible mechanism of photosensitization is characterized in terms of singlet oxygen efficiency of these dyes. Singlet oxygen quantum yields for bromine-substituted dyes are in the range of 0.3-0.5 depending on the solvent. For dye 1 no singlet oxygen production is found. The photodynamic actions of these dyes in different cell lines are tested. It was found that dye 2 and dye 3 are efficient photosensitizers and mediate eradication of K562, EM2, myeloid cell lines (CML) and the SMF-AI rhabdomyosarcoma line.
authors.affiliation: Laboratoire de photophysique moléculaire, Université de Montréal, Québec, Canada.
authors.forename: P
authors.initials: P
authors.lastname: Pal
authors.forename: H
authors.initials: H
authors.lastname: Zeng
authors.forename: G
authors.initials: G
authors.lastname: Durocher
authors.forename: D
authors.initials: D
authors.lastname: Girard
authors.forename: T
authors.initials: T
authors.lastname: Li
authors.forename: A K
authors.initials: AK
authors.lastname: Gupta
authors.forename: R
authors.initials: R
authors.lastname: Giasson
authors.forename: L
authors.initials: L
authors.lastname: Blanchard
authors.forename: L
authors.initials: L
authors.lastname: Gaboury
authors.forename: A
authors.initials: A
authors.lastname: Balassy
authors.forename: C
authors.initials: C
authors.lastname: Turmel
authors.forename: A
authors.initials: A
authors.lastname: Laperrière
authors.forename: L
authors.initials: L
authors.lastname: Villeneuve
mesh_terms: D000818:Animals; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D005456:Fluorescent Dyes / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology*; D006801:Humans; D004915:Leukemia, Erythroblastic, Acute / Q000188:drug therapy; D010777:Photochemistry; D017319:Photosensitizing Agents / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology*; D012208:Rhabdomyosarcoma / Q000188:drug therapy; D012235:Rhodamines / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology*; D014407:Tumor Cells, Cultured
chemical_list: C099827:4,5-dibromorhodamine n-butyl ester; D005456:Fluorescent Dyes; D017319:Photosensitizing Agents; D012235:Rhodamines; C099826:4,5-dibromorhodamine methyl ester