Cranberry Polyphenols on Formation and Virulence of Streptococcus mutans Biofilms

Cranberry harbors several potentially active polyphenolic compounds, and its crude extracts display biological properties against Streptococcus mutans. Objective: The aim of this study was to evaluate the influence of Cranberry constituents on formation and virulence of S. mutans biofilms. Methods: The composition and influence of flavonols (F)-, anthocyanins (A)-, proanthocyanidins (PACs)-rich fractions of cranberry extract on the virulence and development of S. mutans UA159 biofilms were examined. The ability of cranberry components to inhibit the glucan production by purified glucosyltransferases (GTFs) adsorbed to sHA, the membrane-associated F-ATPase and glycolytic activity was determined. Furthermore, we examined whether cranberry components interferes with the viability, development, polysaccharide composition and acidogenicity of S. mutans biofilms. The crude cranberry extract and vehicle solution (10% ethanol, v/v) were used as controls. Results: Flavonols (125 mg/ml) and PACs (500 mg/ml), alone or in combination, inhibited the activities of surface adsorbed GTF B and C (30 to 60% inhibition compared to control, P<0.05); the crude extract inhibited the GTFs activity by 67%±11. The PACs, alone or in combination with A and F, remarkably inhibited the activity of F-ATPase (85-89% inhibition), and the glycolytic pH drop by suspensions of S. mutans cells. Biofilm formation and accumulation were significantly reduced by topical applications of PACs and F, alone or in combination, twice daily with 1 min exposures (P<0.05). The biomass and insoluble glucan content of the biofilms in addition to its acidogenicity were significantly reduced by PACs and F treatments (P<0.05). Anthocyanins were devoid of any significant biological activity on the parameters assessed in this study. Conclusions: Our data show that A-type PACs and flavonols are responsible for the inhibitory properties of cranberry extract against virulence factors involved in S. mutans acidogenicity and biofilm formation. (NIDCR # 1R01DE016139-01)