Microsomal metabolism of the food mutagen 2-amino-3,4,8-trimethyl-3<i>H</i>-imidazo[4,5-<i>f</i>]-quinoxaline to mutagenic metabolites
作者:Henrik Frandsen、Preben A. Nielsen、Spiros Grivas、John C. Larsen
DOI:10.1093/mutage/9.1.59
日期:——
Heterocyclk aromatic amines are formed in the crust of meat during ordinary cooking. These aromatic amines are potent bacterial mutagens and also potent rodent carcinogens. 2-Amino-3,4,8-trimethyl-3H-imidazo[4,5-f]quinoxaline (DiMelQx) is one of the more abundant heterocyclk aromatic amines, accounting for ∼20% of the mutagenic material found in cooked meat. DiMelQx is metabolkally activated, by hepatic microsomes from PCB treated rats, to two major and three minor metabolites. One major and one minor metabolite were identified as 2-hydroxyamino-3,4,8-tri-methyl-3H-lmidazo[4,5-f]quinoxaline and 3,4,8-trimethy1-2-nitro-3H-imidazo[4,5-f]quinoxaline, respectively, confirmed by comparison of HPLC retention times, and UV and mass spectra of synthetic standards. Both metabolites were mutagenic in Salmonella typhimurium TA98 without metabolic activation. The other major metabolite was identified as 2-amino-8-hydroxymethyl-3,4-dimethyl-3H-imidazo[4,5-f]-quinoxaline by mass and NMR spectral analysis. The two remaining minor metabolites were identified as the 2-hydroxy-amino- and 2-nitro- derivatives of 2-amino-8-hydroxy-methyl-3,4dimethyl-3H-imidazo[4,5-f]quinoxaline by UV and mass spectral analysis. Both of these metabolites were mutagenic in S.typhimurium TA98 without metabolic activation.
在普通烹饪过程中,异环芳香胺会在肉的外皮中形成。这些芳香胺是强效细菌诱变剂,也是强效啮齿动物致癌物。2-氨基-3,4,8-三甲基-3H-咪唑并[4,5-f]喹喔啉(DiMelQx)是含量较多的异环芳香胺之一,约占熟肉中诱变物质的20%。DiMelQx在代谢过程中被经多氯联苯处理过的老鼠的肝微粒体激活为两种主要代谢物和三种次要代谢物。一种主要代谢物和一种次要代谢物分别被确定为2-羟基氨基-3,4,8-三甲基-3H-咪唑并[4,5-f]喹喔啉和3,4,8-三甲基-1-2-硝基-3H-咪唑并[4,5-f]喹喔啉,并通过HPLC保留时间、紫外光谱和合成标准的质量谱进行比较得到证实。这两种代谢物在未进行代谢活化的情况下,对鼠伤寒沙门氏菌TA98具有诱变性。通过质谱和核磁共振光谱分析,另一种主要代谢物被确定为2-氨基-8-羟甲基-3,4-二甲基-3H-咪唑并