Occurrence of 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), 2-amino-6-methyldipyrido[1,2-a:3',2'-d]imidazole (Glu-P-1) and other heterocyclic amine mutagens in oil of charred egg yolk (ranyu)

Abstract

Mutagenicity of oil of charred egg yolk (called ranyu in Japanese), which is commercially available and consumed as a health food in Japan, was tested on Salmonella typhimurium strains TA98 and TA100 with and without metabolic activation. Both strains showed a high response to the oil, and the number of His+ revertant colonies with strain TA98 was 15,000-20,000 for 1 g equivalent amount of oil. The mutagens were purified by acid extraction, chloroform extraction after alkalization, dialysis, adsorption to blue cotton, passing through a Sephadex LH-20 column and several stages of high-pressure liquid chromatography with reverse-phase columns. At least 7 heterocyclic amine mutagens were detected. Two of them were suggested to be 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) and 2-amino-6-methyldipyrido [1,2-a:3',2'-d]imidazole (Glu-P-1). One was suggested to be 2-amino-3,4-dimethylimidazo[4,5-f]quinoline (MeIQ). The others were not identified but distinguishable from 12 known heterocyclic amine mutagens. The estimated minimum contents of IQ and Glu-P-1 were 1.1 ng/g and 4.8 ng/g, respectively.