Levels of direct-acting mutagens, total N-nitroso compounds in nitrosated fermented fish products, consumed in a high-risk area for gastric cancer in southern China.
Mutat Res
; 265(2): 211-21, 1992 Feb.
Article
en En
| MEDLINE
| ID: mdl-1370720
ABSTRACT
A high gastric cancer mortality in Fujian province (Peoples Republic of China) has been associated with the consumption of certain salted fermented fish products such as fish sauce (FS). We have investigated the levels and nature of N-nitroso compounds (NOC) and genotoxins present, before and after nitrosation, in 49 FS samples collected from villages in this high-risk area, pooled into six samples. The concentrations of total NOC before nitrosation ranged from 0.2 to 16 mumoles/l, and after nitrosation at pH 2 and pH 7, they rose by up to 4800- and 100-fold, respectively. In nitrosated samples, 40-50% of total NOC was not extractable into organic solvents; volatile N nitrosamines accounted for 1-2% and N-nitrosamino acids for 8-16% of total NOC. None of the FS samples exhibited genotoxic activity, but after nitrosation all were weakly active in the SOS chromotest. The highest SOS-inducing potency was observed with nitrosated ethyl acetate extracts of most samples. The formation of methylating agents was measured by incubation of nitrosated FS with DNA and subsequent analysis of 7-methylguanine adduct. 2 of the 6 nitrosated FS samples caused a slight increase in DNA methylation. 1 pooled home-made FS sample (the only one tested) contained tumour promoter-like substances, as measured by expression of certain EBV genes in Raji cells. HPLC fractionation of ethyl acetate extracts of FS samples allowed identification of three UV-absorbing peaks that, upon nitrosation, produced direct-acting genotoxins. This genotoxicity was partly ascribed to the formation of nitrite-derived arene diazonium cations that were characterized by a coupling reaction with N-ethyl-1-naphthylamine and thin-layer chromatography.
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Bases de datos:
MEDLINE
Asunto principal:
Productos Pesqueros
/
Mutágenos
/
Compuestos Nitrosos
Tipo de estudio:
Etiology_studies
/
Prognostic_studies
/
Risk_factors_studies
Límite:
Humans
País/Región como asunto:
Asia
Idioma:
En
Revista:
Mutat Res
Año:
1992
Tipo del documento:
Article
País de afiliación:
Francia