Chemical and biological studies of a new cigarette that primarily heats tobacco. Part 2. In vitro toxicology of mainstream smoke condensate.

The genotoxic and cytotoxic potential of mainstream cigarette smoke condensate (CSC) from a new cigarette that primarily heats tobacco (TOB-HT) was compared with that of CSC from a Kentucky reference low "tar" cigarette (1R4F) representative of the current US cigarette market, and Kentucky Reference 1R5F, representative of ultra-low "tar" cigarettes on the US market. TOB-HT was evaluated at concentrations which induced concentration-dependent positive responses with 1R4F and 1R5F in an in vitro toxicology test battery which included sister chromatid exchange, chromosome aberration, and neutral red cytotoxicity assays in CHO cells, and the Ames bacterial mutagenicity assay. CSC from 1R4F and 1R5F was positive in the Ames assay with Salmonella typhimurium strains TA98, TA100, TA1538 and TA1537, and negative with TA1535, while CSC from TOB-HT was negative in all five strains. CSC from 1R4F and 1R5F cigarettes was positive in sister chromatid exchange (SCE), chromosome aberration (CA) and neutral red cytotoxicity assays, while CSC from the TOB-HT cigarette yielded negative results in all the above endpoints. These data indicate that in these assays the genotoxic and cytotoxic potential of CSC from the new cigarette that primarily heats tobacco is significantly less than CSC from Kentucky reference 1R4F and 1R5F cigarettes, which are representative of cigarettes currently sold in the US.