Inhibitory Effects of Food-Coloring Agents Derived from Monascus on the Mutagenicity of Heterocyclic Amines

Red and yellow pigments extracted from Monascus anka and Monascus purpureus (collectively called Beni-Koji) are being used for food coloration. In the Ames Salmonella assay, these pigments themselves showed individually no mutagenic activity, and both of them inhibited the mutagenicity of 3-hydroxyamino-1-methyl-5H-pyrido[4,3-b]indole [Trp-P-2(NHOH)], the activated form of Trp-P-2 (3-amino-1-methyl-5H-pyrido[4,3-b]indole). Laccaic acid and kaki pigment also inhibited the mutagenicity of Trp-P-2(NHOH). Monascus dyes, both yellow and red, inhibited the mutagenicity of metabolically activated 2-amino-3-methylimidazo[4,5-f]quinoline, 2-amino-3,4-dimethylimidazo-[4,5-f]quinoline, and cooked-meat extract. Incubation of Trp-P-2(NHOH) with the Monascus dyes resulted in a rapid disappearance of the mutagen. Therefore, a role of the dyes in the inhibition of the mutagenicity appears to be acceleration of the decomposition of the activated mutagens.