Mutagenicity of soy sauce treated with nitrite in the presence of ethanol or alcoholic beverages

Sensitivity of mouse oocytes to nicotine-induced perturbations during oocyte meiotic maturation and aneuploidy in vivo and in vitro

Oocyte meiosis is sensitive to endogenous and exogenous perturbations that upset the temporal sequence of biochemical reactions during oocyte maturation (OM) and predispose oocytes to aneuploidy. Nicotine is an alkaloid that has been reported to disrupt the rate of OM, reduce ovulation and fertilization rates, and increase diploidy. The objective of this study was to test the hypothesis that nicotine perturbs the rate of OM and induces aneuploidy in mouse oocytes in vivo and in vitro. Female mice were given 7.5 IU pregnant mare's serum and either 0, 5.0, 7.5, or 10 mg/kg nicotine in vivo at -3, 0, and +3 h relative to a 5 IU injection of HCG. Oocytes were also cultured in vitro in the presence of 0, 1.0, 5.0, or 10.0 mmol/l nicotine. In vivo, significant (P < 0.05) differences in the proportions of oocytes with premature centromere separation and premature anaphase were found at 10.0 mg/kg nicotine suggesting that the rate of OM was advanced. Also, at this dose the proportion of ovulated oocytes was reduced by approximately 50% relative to controls. In vitro, only non-significant differences were found among the parameters measured. Although nicotine reduced the ovulation rate and perturbed the rate of OM in vivo, these data show that the rate of aneuploidy was not significantly elevated.

Inhibitory effects of tea extracts on the mutagenicity of 1-methyl-1, 2,3,4-tetrahydro-beta-carboline-3-carboxylic acid on treatment with nitrite in the presence of ethanol

It has been shown that the mutagenicity of 1-methyl-1,2,3, 4-tetrahydro-beta-carboline-3-carboxylic acid (MTCCA), a major mutagen precursor in soy sauce on treatment with nitrite and ethanol, was strongly decreased by the addition of hot water extracts of green, black and oolong teas in the reaction mixture when it was treated with 50mM nitrite at pH3.0, 37 degrees C for 60min in the presence of 7.5% ethanol. The mutagenicity-decreasing activity of the teas was scarcely decreased by washing the teas with chloroform and benzene and was partly decreased by butanol and ethyl acetate. Typical polyphenols such as catechins were shown to have the antimutagenicity dose dependently. The antimutagenicity and the reducing power of tea extracts gave a positive good correlation. The results suggest that the mutagenicity of MTCCA on treatment with nitrite in the presence of ethanol may be decreased by the mixed fractions of lyophilic components such as polyphenols, which have high reducing power such as catechins and the other compounds which have little reducing power including the derivatives of the catechins and so on. Although the antimutagenicity of teas and catechins was also considerably effective when they were added after the nitrosation, that of black tea and some catechins was less effective.

Inhibitory effects of citrus fruits on the mutagenicity of 1-methyl-1,2,3,4-tetrahydro-beta-carboline-3-carboxylic acid treated with nitrite in the presence of ethanol

It has been shown that the mutagenicity of 1-methyl-1,2,3,4-tetrahydro-beta-carboline-3-carboxylic acid (MTCCA), a mutagen precursor in soy sauce treated with nitrite, was strongly increased when it was treated with nitrite in the presence of alcohols. We found that the mutagenicity of MTCCA treated with 50 mM nitrite at pH 3, 37 degrees C for 60 min in the presence of 7.5% ethanol was reduced by the addition of citrus fruits sudachi (Citrus sudachi), lemon (C. limon) and yuzu (C. junos), to the reaction mixture. The mutagenicity-reducing activity per weight of flavedos (outer colored portions of peel) of the citrus fruits was considerably higher than that of the juices. The juices of the other citrus fruits commercially available in Japan also had mutagenicity-reducing activity against the nitrite-treated MTCCA. Among the many components of citrus fruits, dietary fibers lignin and pectin showed strong antimutagenic activity in the reaction mixture, suggesting that the mixed fractions of these components including lignin, pectin, D-limonene, naringin, hesperidin, ascorbic acid and citric acid reduce the mutagenicity of MTCCA in the reaction mixture containing nitrite and ethanol.

Mutagenicity of 1-methyl-1,2,3,4-tetrahydro-beta-carboline-3-carboxylic acid treated with nitrite in the presence of alcohols

The mutagenicity of a product produced from 1-methyl-1,2,3,4-tetrahydro-beta-carboline-3-carboxylic acid (MTCCA), which is a component in soy sauce, after treatment with 50 mM nitrite at pH 3, 37 degrees C, for 60 min in the presence of 7.5% ethanol was much higher than that in the absence of ethanol during the nitrite treatment. The enhancement of the mutagenicity of nitrite-treated MTCCA by ethanol required simultaneous treatment of MTCCA with nitrite and ethanol. The mutagenicity of MTCCA treated with nitrite in the presence and absence of ethanol was detected in the same fractions on HPLC and was highest for Salmonella typhimurium strain YG1029 possessing elevated O-acetyltransferase activity among the several Salmonella test strains, suggesting that the same mutagen belonging to aromatic compounds was produced both in the presence and absence of ethanol. Methanol, n-propanol and isopropanol as well as ethanol were also observed to have an augmenting effect. However, the sugars glucose and sucrose had no effect. When MTCCA was treated with nitrite in the presence of commercial alcoholic beverages equivalent to 1.25-10% ethanol, Japanese 'sake' and 'shochu' were demonstrated to have a highly augmenting effect and beer, wine, whisky and brandy to have a mildly augmenting effect.