title: Assessment of diphenylcyclopropenone for photochemically induced mutagenicity in the Ames assay.
abstract: The photochemical conversion of diphenylcyclopropenone to diphenylacetylene has recently been reported. Diphenylcyclopropenone is used in the treatment of alopecia areata and is nonmutagenic in a limited Ames assay. We examined diphenylcyclopropenone and diphenylacetylene, as well as synthetic precursors of diphenylcyclopropenone--dibenzylketone and alpha,alpha'-dibromodibenzylketone--for mutagenicity against TA100, TA98, TA102, UTH8413, and UTH8414. All compounds were nonmutagenic except alpha,alpha'-dibromodibenzylketone, which was a potent mutagen in TA100 with and without S-9 activation. The effect of photochemical activation of diphenylcyclopropenone in the presence of bacteria demonstrated mutagenicity in UTH8413 (two times background) at 10 micrograms/plate with S-9 microsomal activation. 8-Methoxypsoralen produces a mutagenic response in TA102 at 0.1 microgram/plate with 60 seconds of exposure to 350 nm light. In vitro photochemically activated Ames assay with S-9 microsomal fraction may enhance the trapping of short-lived photochemically produced high-energy mutagenic intermediates. This technique offers exciting opportunities to trap high-energy intermediates that may play an important role in mutagenesis. This method can be applied to a variety of topically applied dermatologic agents, potentially subjected to photochemical changes in normal use.
authors.affiliation: Department of Dermatology, Medical College of Virginia, Richmond.
authors.forename: M G
authors.initials: MG
authors.lastname: Wilkerson
authors.forename: T H
authors.initials: TH
authors.lastname: Connor
authors.forename: J
authors.initials: J
authors.lastname: Henkin
authors.forename: J K
authors.initials: JK
authors.lastname: Wilkin
authors.forename: T S
authors.initials: TS
authors.lastname: Matney
mesh_terms: D003521:Cyclopropanes / Q000528:radiation effects / Q000633:toxicity*; D011564:Furocoumarins / Q000528:radiation effects / Q000633:toxicity; D009152:Mutagenicity Tests; D009153:Mutagens; D012486:Salmonella typhimurium / Q000187:drug effects / Q000528:radiation effects; D014466:Ultraviolet Rays
chemical_list: D003521:Cyclopropanes; D011564:Furocoumarins; D009153:Mutagens; C029402:diphenylcyclopropenone