Background: Streptococcus mutans (S. mutans) plays a major role in the formation of dental caries. The aim of this study was to examine the effect of the green tea polyphenol, epigallocatechin gallate (EGCG), on biofilm formation of S. mutans. Methods: Following exposure to increasing concentrations of EGCG, the planktonic growth was measured by optical density and the biofilm biomass was quantified by crystal violet staining. Exopolysaccharides (EPS) production was visualized by confocal scanning laser microscopy, and the bacterial DNA content was determined by quantitative polymerase chain reaction (qPCR). Gene expression of selected genes was analyzed by real time (RT)-qPCR and membrane potential was examined by flow cytometry. Results: We observed that EGCG inhibited in a dose-dependent manner both the planktonic growth and the biofilm formation of S. mutans. Significant reduction of S. mutans biofilm formation, DNA content, and EPS production was observed at 2.2–4.4 mg/ml EGCG. EGCG reduced the expression of gtfB, gtfC and ftf genes involved in EPS production, and the nox and sodA genes involved in the protection against oxidative stress. Moreover, EGCG caused an immediate change in membrane potential. Conclusions: EGCG, a natural polyphenol, has a significant inhibitory effect on S. mutans dental biofilm formation and EPS production, and thus might be a potential drug in preventing dental caries.
Bibliographical noteFunding Information:
The authors would like to thank Dr. Vitaky Gutkin at The Harvey M. Krueger Family Center for Nanoscience and Nanotechnology at the Edmond J. Safra Campus of The Hebrew University of Jerusalem for his valuable assistance with the HR-SEM analysis, and Dr. Yael Feinstein-Rotkopf at the Core Research Facility of The Hadassah Medical School for managing the Nikon Yokogawa W1 Spinning Disk microscope.
© 2021, The Author(s).
- Oral bacteria