Inhibitory effect of the combination of xylitol and funoran on Streptococcus mutans biofilm formation on the uncoated surface.

We investigated the effect of xylitol or/and funoran on biofilm formation by Streptococcus mutans, one of cariogenic bacteria, on the surfaces coated and non-coated with saliva. Effects of xylitol and/or funoran were observed on biofilm formation of S. mutans in non-coated and salivary components-coated polystyrene microtiter 96-well plates (s-plate) and flow cell system. Xylitol did not strongly affect biofilm formation of S. mutans UA159 on non-coated and s-plates and, however, changed the quality of the biofilm on the cells in a flow cell system. Funoran had effects on biofilm formation, and the combination of xylitol and funoran strongly inhibited S. mutans biofilm formation on non-coated plates. In particular, funoran had inactivation effects on membrane vesicles (MVs) and inhibited MV-dependent biofilm formation of S. mutans on non-coated plate surfaces but not on the s-plate. These findings suggest that the combination of xylitol and funoran might be useful to remove the oral biofilm formation in elderly individuals with decreased saliva production. This result suggests that the synergistic effect of funoran and xylitol might be useful for the prevention of biofilm-associated diseases such as dental caries in saliva-decreased patients such as elderly patients.