Evaluation of the biological activity of cigarette‐smoke condensate fractions using six in vitro short‐term tests

Abstract

The biological activity of the volatile part of the particulate phase of cigarette‐smoke condensate, the semivolatile fraction, has been examined, since the constituents of this material are accessible to selective filtration. Such a process offers a possibility to reduce the biological activity of total cigarette smoke without appreciably affecting the taste. Cigarette‐smoke condensate, obtained from domestic American blend type cigarettes, was therefore separated into a nonvolatile and a semivolatile fraction, and the latter was fractionated by liquid‐liquid extractions into four subfractions; acids, phenols, bases, and neutrals. The biological activity of these fractions was investigated using six in vitro short‐term tests, of which two, the Ames test and the induction of sister chromatid exchanges, provided information on their genotoxicity, and the other four provided information on their cytotoxicity by measuring inhibition of cell growth, Inhibition of oxidative metabolism, membrane damage, and ciliotoxicity.

Sister chromatid exchanges were found to be induced by the total condensate, the nonvolatile and the semivolatile fractions, and the subfractions derived from the semivolatlle fraction, except the bases. The Ames test showed the total condensate and the non‐volatile fraction to contain direct‐acting base‐pair mutagens as well as indirect‐acting frameshift mutagens. While the semivolatile fraction was found nonmutagenlc, two of its subtractions, acids and phenols, were shown to contain base‐pair mutagens, which did not require metabolic activation.

The total condensate and the nonvolatile and semivolatile fractions showed similar activity in the four cytotoxicity tests. Of the semivolatile subtractions, the acids and the phenols exhibited the highest activity and the bases the lowest; the toxicity observed for the neutrals varied with the test system used.