The antimicrobial efficacy of Fructus mume extract on orthodontic bracket: A monospecies-biofilm model study in vitro

Objective: The aim of this study was to evaluate the antimicrobial efficacy of Traditional Chinese Medicine Fructus mume on a monospecies-biofilm model established on orthodontic brackets in vitro. Materials and methods: The antimicrobial effect of Fructus mume aqueous extract on the planktonic Streptococcus mutans (S. mutans) was tested by microdilution method (MIC). The cell viability of S. mutans biofilm on Damon3 MX bracket (Ormco, USA) after exposed to Fructus mume extract was quantified by XTT reduction assay. Visualization of the samples was performed by fluorescence microscope and confocal laser scanning microscopy (CLSM). Results: HPLC analysis revealed that the main compounds of Fructus mume are organic acids. The MIC of Fructus mume extract on the planktonic S. mutans was 50 mg/mL. The optical density (OD) values, measured by XTT reduction assay from S. mutans biofilms after 1-min exposure to different test agents, demonstrated that the cell viability of S. mutans biofilms exposed to 250 mg/mL Fructus mume extract < BHI (-) (p < 0.01). Microscope image showed that Fructus mume extract obviously increased the amount of dead bacteria on the surface of bracket. Conclusion: Fructus mume extract showed antimicrobial effect on S. mutans biofilm on orthodontic bracket in vitro which may indicate its potential use as an oral antimicrobial agent for orthodontic patients. (C) 2010 Elsevier Ltd. All rights reserved.