Evaluation of POMx lozenges' antimicrobial activity against saliva-derived biofilm

OBJECTIVES: Pomegranates have long been associated with myriad health benefits, including antimicrobial activity against dental plaque. This study evaluates the antimicrobial activity of two POMx Wonderful lozenges containing polyphenols extracted from pomegranates against oral bacteria grown in a biofilm environment. METHODS: The lozenges tested containing 50 mg GAE/ lozenge (Lozenge-50) and 100 mg GAE/ lozenge (Lozenge-100) were dissolved one each in 10 ml microorganism free saliva. For biofilm growth pooled saliva from 6 subjects was processed and 1.25x10⁶ of a spectinomycin-resistant Streptococcus mutans derivative was added to the salivary bacteria to yield saliva-derived biofilms containing about 10% of this cariogenic oral species. Overnight grown biofilms were subjected to treatment with lozenge-50 and lozenge-100 solutions for 1, 5, 10, 15, 20 and 30 min. The biofilms were thoroughly disrupted, and biofilm cell survival was assessed by determining CFUs on BHI plates (all biofilm cells) and BHI containing 800 µg/ml spectinomycin (S. mutans). To test the effect of POMx lozenges on salivary bacteria attachment to surfaces, saliva was collected and co-inoculated with the treatment solutions for 8 hours. Biofilm formation was monitored with a live imaging system. RESULTS: Greatly reduced overall biofilm viability was observed starting at 5 min treatment with POMx lozenge-100, eliminating 50% of the total population. Lozenge-50 lagged behind for 5 min and displayed a similar killing at 10 min treatment. S. mutans appeared to be particularly sensitive to these products by demonstrating a more than 10-fold greater reduction compared to the total biofilm population. Both lozenges prevented biofilm attachment and growth upon co-inocculation with salivary bacteria CONCLUSIONS: The pomegranate extract based lozenges tested exhibited significant antimicrobial activity against saliva-derived biofilms and were found to be particularly effective against the major cariogenic agent S. mutans. They were also effective in inhibiting biofilm formation for up to 8 hours.