title: Mutagenic activity in smokeless tobacco products sold in the USA.
abstract: Aqueous extracts of smokeless tobacco products (snuff, chewing tobacco, smokeless tobacco) sold in the USA are mutagenic in the base-pair substitution mutant, Salmonella typhimurium TA100, with potencies of 8000-16,000 revertants/g tobacco. Most of the activity failed to extract into organic solvents at neutral pH and a portion of the activity extracted into organic solvents at acidic pH. The tobacco-specific nitrosamines, N-nitrosonornicotine and (4-methylnitrosamino)-1-(3-pyridyl)-1-butanone did not exhibit this behavior. Mutagenesis required metabolic activation (liver S-9 fraction plus NADPH) and a weakly acidic liquid preincubation. The mutagenesis behavior is typical of nitrosamines, and suggests that N-nitrosamines are responsible for at least some of the mutagenic activity in the extracts.
mesh_terms: D006863:Hydrogen-Ion Concentration; D009153:Mutagens / Q000032:analysis* / Q000302:isolation & purification; D009602:Nitrosamines / Q000032:analysis; D010947:Plants, Toxic; D014026:Nicotiana / Q000032:analysis*; D014030:Tobacco, Smokeless / Q000032:analysis*
chemical_list: D009153:Mutagens; D009602:Nitrosamines