title: Phototoxic and photochemical properties of sanguinarine.
abstract: Sanguinarine, a commercial drug exhibiting antimicrobial and antitumor properties, was studied with respect to its basic photochemical characteristics and also with regard to its phototoxicity to mosquito larvae (Aedes atropalpus). Sanguinarine proved to be clearly phototoxic to larvae, with an LD50 of 0.096 mg/mL with near UV exposure as compared with 23.3 mg/mL without. Flash photolysis experiments enabled the study of the triplet state of sanguinarine to be undertaken. Quenching by oxygen occurs with a rate constant of 6 x 10(9) M-1s-1 and time-resolved emission studies indicate that sanguinarine produces a significant amount of singlet oxygen (phi delta = 0.16) as does the isoquinoline alkaloid, berberine (phi delta = 0.25). These values represent the first direct quantitative measurements of photosensitization parameters of these compounds. Additionally, sanguinarine exhibits efficient electron donation properties, undergoing reaction with methyl viologen with a rate constant greater than 10(10) M-1s-1, but is a poor electron acceptor. Phototoxicity of sanguinarine can thus be explained in terms of its photosensitization properties.
authors.affiliation: Ottawa Carleton Biology Institute, University of Ottawa Campus, Ontario, Canada.
authors.forename: J T
authors.initials: JT
authors.lastname: Arnason
authors.forename: B
authors.initials: B
authors.lastname: Guèrin
authors.forename: M M
authors.initials: MM
authors.lastname: Kraml
authors.forename: B
authors.initials: B
authors.lastname: Mehta
authors.forename: R W
authors.initials: RW
authors.lastname: Redmond
authors.forename: J C
authors.initials: JC
authors.lastname: Scaiano
mesh_terms: D000330:Aedes / Q000187:drug effects* / Q000528:radiation effects; D000470:Alkaloids / Q000737:chemistry* / Q000633:toxicity*; D000818:Animals; D000890:Anti-Infective Agents / Q000737:chemistry* / Q000633:toxicity*; D053119:Benzophenanthridines; D007546:Isoquinolines; D007814:Larva; D007928:Lethal Dose 50; D010777:Photochemistry; D011679:Pupa; D014466:Ultraviolet Rays
chemical_list: D000470:Alkaloids; D000890:Anti-Infective Agents; D053119:Benzophenanthridines; D007546:Isoquinolines; C005705:sanguinarine