The occurrence of tobacco-specific nitrosamines in oral tobacco products and their potential formation under simulated gastric conditions.
The levels of the tobacco-specific nitrosamines: N-nitrosoanabasine, N-nitrosoanatabine, N-nitrosonornicotine and 4-(N-nitrosomethylamino)-1-(3-pyridyl)-1-butanone in a variety of chewing tobaccos, oral snuffs, masheri and zarda samples were determined. The potential endogenous formation of tobacco-specific nitrosamines was estimated by incubation of tobacco samples at pH 2.0 for 1 hr at 37 degrees C and over the pH range 1.0 to 5.5 under conditions simulating the normal fasting stomach, with a constant nitrite concentration of 25 microM. Under the simulated gastric conditions, N-nitrosoanabasine, N-nitrosoanatabine and N-nitrosonornicotine were formed, and maximum formation of these tobacco-specific nitrosamines occurred at pH 2.5. Nicotine, the major alkaloid present in tobacco and precursor to N-nitrosonornicotine and 4-(N-nitrosomethylamino)-1-(3-pyridyl)-1-butanone, was not nitrosated. The formation of N-nitrosonornicotine resulted from nitrosation of nornicotine, another alkaloid also present in tobacco. Under the acidic simulated gastric conditions, slight decomposition of 4-(N-nitrosomethyl-amino)-1-(3-pyridyl)-1-butanone via transnitrosation was observed.
Tricker
A R
AR
Institute of Toxicology & Chemotherapy, German Cancer Research Center, Heidelberg.
Haubner
R
R
Spiegelhalder
B
B
Preussmann
R
R
D002273:Carcinogens / Q000032:analysis* / Q000378:metabolism; D005753:Gastric Mucosa / Q000378:metabolism*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D009602:Nitrosamines / Q000032:analysis* / Q000378:metabolism; D010947:Plants, Toxic; D014026:Nicotiana / Q000032:analysis*
D002273:Carcinogens; D009602:Nitrosamines; C016583:4-(N-methyl-N-nitrosamino)-1-(3-pyridyl)-1-butanone; C032978:N'-nitrosoanatabine; C008655:N'-nitrosonornicotine