2-amino-3,4,8-trimethylimidazo quinoxaline

DiMeIQx 2-amino-3,4,8-trimethylimidazo-[/] quinoxaline nh2 Trp-P-1 3-amino-l,4-dimethyl-5H-pyrido[4,3-/)Jindole CH3 0X1. CH3 Trp-P-2 3-amino-l-methyl-5H-pyrido[4,3-/)]indole ch3 f S X" N... 

Figure 11.4. Structures of various heterocyclic amines. IQ is 2-amino-3-methylimidazo-quinoline. MelQx is 2-amino-3,8-dimethylLtnidazo-quinoxalme. 4,8-DiMelQx is 2-amino-3,4,8-trimethylimidazo-quinoxaline. PhIP is 2-amino-l-methyl-6-phenylimidazo-pyridine. These and other related compounds can be found in fried or broil beef, fish, and chicken, but can also be created by cooking mixtures of creatinine, amino acids, and glucose. Microwave cooking, or cooking in aluminum foil, reduces the formation of heterocyclic amines. (From Sugimura, 1997.)...

Figure 13.8 Mutagenic and carcinogenic heterocyclic amines (a) IQ (2-amino-3-methylimidazo[4,5-/ quinoline), (b) IQx (2-amino-3-methylimidazo[4,5-/ quinoxaline), (c) PhIP, (2-amino-l-methyl-6-phenylimidazo[4,5- ] pyridine), (d) 1,5,6-TMIP (2-amino-l,5,6-trimethylimidazo[4,5-6] p5ridine).

In very heavily smoked products there may also be small amounts of HAs, usually less than 1 ng per g. The smoke-dried bonito (baikan) contains 2 to 3 ng HAs per g (Kikugawa et al., 1986). Smoke-dried mackerel, produced by smoke-drying at 80 to 140°C for two hours, repeated several times, has been found to contain 2-amino-3,8-dimethylimidazo[4,5-/ quinoxaline (0.8 ng per g), and a smaller quantity of 2-amino-3,4,8-trimethylimidazo[4,5-/ quinoxaline (ICato, Kikugawa and Hayatsu, 1986). 

Z-aminO 1 -methy 1 6 phenylimidazo [4,5-b]-pyridine 2 aminO 3,7,8 trimethylimidazo[4,5 f]quinoxaline 2 aminO 3,4,7,8 tetramethyl 3H imidazO [4,5 f]quinoxaline inoxaline 3 aminO l,4 dimethyl SH pyrid [4,3 b] indole (Trp P I) and 3 aminO l methyl 5H pyrido [4,3 b]indole induced mutagenesis. Metabolic activation was required for positive results b... 

Frandson H. Excretion of DNA adducts of 2-amino-l -methyl-6-phenylimidazo[4,5b]pyridine and 2-amino-3,4,8-trimethylimidazo[4, 5-f]quinoxaline, PhIP-dG, PhIP-DNA and DiMelQx-DNA from the rat. Carcinogenesis 1997 18 1555-1560. 

Eight heterocyclic aromatic amine carcinogens were extracted from cooked meats. A Cjg column and a complex 30-min 95/5- 45/55 water (lOmM triethylamine phosphate at pH 3.6)/acetonitrile resolved 2-amino-1-methyl-, 2-amino-3,8-dimethyl-, and 2-amino-3,4,8-trimethylimidazo[4,5-/]quinoxaline with monitoring by UV (A = 262 nm) and fluorescence (A = 307 nm, ex 370 nm, em). A 40-min 95/5—>-20/80 water (25 mM triethylamine phosphate at pH 3.6)/acetonitriIe gradient on the same column resolved 2-amino-1,6-dimethylimi-... 

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