Fig. 4

Synergistic inhibition of biofilm formation by extract combinations against S. mutans. The synergistic inhibitory activity of Glycyrrhizae Radix extract and Rubi Fructus extract (A) and glycyrrhizin and ellagic acid (B) against the formation of biofilm by S. mutans. A control was administered, either distilled water (A) or DMSO (B). The amount of biofilm was measured by the absorbance of crystal violet (CV) at 595 nm. Values that differ from the control with a 95% confidence level are marked with an asterisk on top of the bars