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The addition of 1,8-pyrenequinone into the assay system containing rat liver homogenates (S-9) caused an approximately 10-fold increase in the mutagenicity of 2-acetylaminofluorene (AAF) in the current Salmonella reversion assay system. Since no chemical reaction between 1,8-pyrenequinone and AAF was observed, the in vitro effects of 1,8-pyrenequinone on the metabolisms of AAF with S-9 mix were studied. The enhancement of mutagenicity by 1,8-pyrenequinone was not dependent on the dose of NADPH under the present assay condition. The mutagenicity of AAF was increased approximately 4-fold by the addition of 1,8-pyrenequinone into microsomes, whereas it remained at the spontaneous level in the presence of cytosol. However, by reconstituting microsomes with cytosol, the mutagenicity enhancing activity was recovered to the original level. Since 1,8-pyrenequinone inhibited the AAF hydroxylase activity, chemical analysis of the incubation mixture of AAF was tried. This indicated that a higher amount of unmetaboli...

Mutation enhancing activity of the mutagenicity of 2-acetylaminofluorene (AAF) in the fractions of cellulose pyrolysate toward Salmonella typhimurium TA98 was determined.The eluate with 50% benzene in hexane from silica gel column showed the highest activity, and this portion was further fractionated by Sephadex LH-20 column, thin layer and gas chromatography to separate the active components.Results indicated that some of polycyclic aromatic hydrocarbons, such as anthracene, phenanthrene and pyrene, and their derivatives in the pyrolysate might contribute to enhancement of the mutagenicity of AAF.

Carbohydrate pyrolysates obtained at 700°C intensively enhanced mutagenicities of several mutagenic agents on Salmonella typhimurium. The pyrolysates obtained by heating from 1 to 15 min had an enhancing effect on the mutagenicity of a similar level. Of the 8 kinds of carbohydrates tested, sucrose pyrolysate showed the highest enhancing effect. The enhancement of mutagenicity by sucrose pyrolysate was much more effective on aromatic amines such as 2-aminofiuorene and 2-aminoanthracene than on polycyclic aromatic hydrocarbons. The enhancing effect of sucrose pyrolysate was exhibited in the presence of a metabolic activation system.

Pyrene, 1-methylpyrene and 1-hydroxypyrene were isolated and identified as active principles in the pyrolysis product of cellulose which enhances mutagenicity of 2-acetylaminofluorene. 1-Hydroxypyrene was first identified from combustion products of naturally occurring materials.It was noted that the four ring system of polycyclic aromatic hydrocarbons showed the enhancement of mutagenicity.