PubMed · 3325772
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
R Benigni. 1987. Mutagenicity testing.. https://doi.org/10.1093/mutage%2F2.5.411
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
Explore the source record for details and available documents.
BACKGROUND: Moist snuff is the only tobacco product in the United States with increasing sales (an increase of 38.4% between 1981 and 1993) and with increased consumption, primarily by male adolescents aged 12-18 years old and young adults aged 19 years old or older. It is known from previous studies that levels of nicotine and the proportion of unprotonated (free) nicotine, as well as the pH, which affects nicotine delivery, vary considerably among the leading snuff brands. Whether concentrations of major carcinogens, such as the nicotine-derived tobacco-specific N-nitrosamines (TSNAs), like N'-nitrosonornicotine (NNN) and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), also vary among these brands has not been determined previously. PURPOSE: Our purpose was threefold: 1) to determine the concentrations of major carcinogenic nicotine-derived N-nitrosamines in each of the five most popular moist snuff brands; 2) to analyze the quantitative differences in the various snuff components (e.g., NNN) between two major brand categories: a category comprising the brands known to have high levels of unprotonated nicotine (Copenhagen, Skoal fine cut, and Kodiak) versus a category comprising the brands known to have low levels (Hawken and Skoal Bandits); and 3) to compare the differences in the concentrations of nicotine (previously determined), NNN, NNK, and total TSNAs between these two major brand categories. METHODS: Three boxes of each of the five leading U.S. moist snuff brands were bought in July 1994 from retailers in six areas and transferred immediately to the analytical laboratory. After extraction, N-nitrosamino acids and TSNAs were determined on a gas chromatograph interfaced with a thermal energy analyzer (GC-TEA) and integrator. Each 5-g sample of ground, freeze-dried tobacco was extracted twice, and each extract was analyzed twice by GC-TEA. All P values reported are two sided. RESULTS: Copenhagen, Skoal fine cut, and Kodiak as a group had statistically significant higher levels of nicotine (P = .0017), NNN (P < .0001), NNK (P = .0119), and total TSNAs (P < .0001) than the Hawken and Skoal Bandits group. Concentrations (means +/- SD) of nicotine, NNN, NNK, and total TSNAs comparing the two major brand categories are as follows: nicotine--11.6 +/- 1.01 mg/g versus 6.96 +/- 3.62 mg/g (P = .0017), NNN--7.74 +/- 1.70 micrograms/g versus 4.17 +/- 1.35 micrograms/g (P < .0001), NNK--1.23 +/- 0.68 micrograms/g versus 0.61 +/- 0.41 micrograms/g (P = .0119), and total TSNAs--14.3 +/- 3.82 micrograms/g versus 6.3 +/- 2.56 micrograms/g (P < .0001). CONCLUSIONS: The three leading U.S. snuff brands (Copenhagen, Skoal fine cut, and Kodiak; making up 92% of the U.S. market) showed not only high levels of pH, nicotine, and unprotonated (free) nicotine, but also high concentrations of the strongly carcinogenic TSNAs in comparison with the fourth and fifth best selling moist snuff brands, Hawken and Skoal Bandits (3% of the U.S. market).
3-Alkyl-1,2,3-oxadiazolinium ions 1 have been proposed as reactive intermediates in the activation of (2-hydroxyethyl)nitrosamines. The reaction of 3-methyl-1,2,3-oxadiazolinium tosylate (1a), 2-ethyl-1-methoxy-2-phenyldiazenium tetrafluoroborate (3), and 3-phenyl-1,2,3-oxadiazolinium triflate (1b) with thiols was investigated to determine the behavior of these compounds toward typical "cellular nucleophiles". Each of these substances oxidizes benzenethiol to diphenyl disulfide. The reaction in aqueous buffer at pH 7.4 is rapid. Reaction of 1b with benzenethiol gives, in addition to the disulfide, benzene, biphenyl, azobenzene, diphenyl sulfide, aniline, and glycolaldehyde. Similar products are obtained from 3. Phenyldiazene is postulated as an intermediate in this process, and its generation from phenyldiazoformate in the presence of benzenethiol gives similar products. Diazenes are presumed to arise by proton abstraction from the CH adjacent to N. The kinetics of reaction of 1a with N-acetylcysteine to give the corresponding disulfide show first order dependence on each reactant and base catalysis. The data from these model chemical experiments suggest that 1,2,3-oxadiazolinium ions could react with abundant thiols in cells to lead to either their detoxification or radical processes emanating from diazenes. The occurrence of thiol-oxadiazolinium ion redox transformations could modulate the alkylation chemistry of these substances as well.