Assessment of Listerine Cool Mint mouthwash influence on possible DNA damage measured by buccal micronucleus cytome assay-preliminary results

Listerine is a brand of mouthwash most used worldwide in oral hygene maintainance.  With its antimicrobic and antifungal characteristics, it can stop/diminish plaque and gingivitis development. Among different types of this mouthwash, all 5 ingredients of Listerine Cool Mint, 21.6% ethanol and 4 herbal extracts-thymol, menthol, eucalyptol and methyl salicylate, have shown capacity to cause cell damage and buccal epithelial cells are in direct contact. Buccal micronucleus cytome assay (BMN) measures changes in differentiation as the frequency of basal/differentiated, binuclear, and cells in different phases of cell death-apoptosis/necrosis (cells with condensed chromatin, karriorhectic, pycnotic and karyolitic cells) and changes in genomic instability measured as micronucleus or nuclear buds/broken eggs frequency. Samples from 10 healthy individuals using Listerine Cool Mint mouthwash twice/day during two-week treatment were analyzed before and after the treatment. There was no significant influence on cell differentiation and genomic instability on the group level, although micronucleus frequency (MN) of entire group was higher after the treatment (1 vs. 1.5). We found interindividual differences and showed that strong alcoholic drinks consumers had higher MN. Future studies should include more individuals, especially with regular alcohol consummation for analysis of possible synergistic influence and therefore higher risk of genomic instability, together with genetic polymorphisms in enzymes responsible for metabolism of ethanol, since they can drastically influence the time duration of ethanol exposure and its metabolite acetaldehyde and also have an impact on genomic instability and possible development of oral squamous cell cancer.