Figure 1.

The structure of astilbin and the inhibition of S. mutans SrtA by astilbin in vitro. (A) The chemical structure of astilbin. (B) The inhibitory effect of astilbin against the SrtA of S. mutans. The purified SrtA was incubated with or without different concentrations of astilbin at 37 °C for 1 h, then the fluorescent substrate peptide was added, and the plate was incubated for 1 h. The fluorescence intensity of each well was measured with an excitation wavelength of 350 nm and an emission wavelength of 495 nm. The values indicate the mean values of three independent experiments. The error bars represent the standard deviations.