Cell transformation activities of abietic acid and dehydroabietic acid: safety assessment of possible contaminants in paper and paperboard for food contact use.

Abietic acid (AA) and dehydroabietic acid (DHA) have been detected in virgin paper products and recycled paper products used for food packaging. In order to evaluate the cell transformation activities of AA and DHA, the Bhas 42 cell-transformation assay for initiation and promotion was carried out. Tested in the initiation stage, AA and DHA did not significantly increase transformation frequencies. On the other hand, both chemicals induced transformed foci dose dependently at the promotion stage. The highest transformed foci density induced by AA was about 13 foci/well at 60 nmol ml(-1), and that of DHA was about 16 foci/well at 40 nmol ml(-1) (solvent control = 2.3 +/- 1.4 foci/well). The present results suggest that AA and DHA may have tumour-promoting potential.