In vitro activity of xanthorrhizol against Streptococcus mutans biofilms

Aims: We determined the effect of xanthorrhizol (XTZ) purified from the rhizome of Curcuma xanthorrhiza Roxb. on the Streptococcus mutans biofilms in vitro. Methods and Results: The biofilms of S. mutans at different phases of growth were exposed to XTZ at different concentrations (5, 10 and 50 μmol l^-1) and for different time exposures (1, 10, 30 and 60 min). The results demonstrated that the activity of XTZ in removing S. mutans biofilm was dependent on the concentration, exposure time and the phase growth of biofilm. A concentration of 5 μmol l^-1 of XTZ completely inhibited biofilm formation by S. mutans at adherent phases of growth, whereas 50 μmol l ^-1 of XTZ removed 76% of biofilm at q1plateau accumulated phase when exposed to S. mutans biofilm for 60 min. Conclusions: Xanthorrhizol isolated from an edible plant (C. xanthorrhiza Roxb.) shows promise as an antibacterial agent for inhibiting and removing S. mutans biofilms in vitro. Significance and Impact of the Study: XTZ could be used as a potential antibacterial agent against biofilm formation by S. mutans.