Effect of Catechin Powdered Green Tea on Oral Bacterium

Abstract

Purpose: The purpose of the present study was to evaluate the antibacterial properties and the morphological change in oral bacteria by catechin powdered green tea (catechin). Method: Streptococcus mutans and Streptococcus sanguinis were used in this study. Both bacterial strains were inoculated in Trypticase Soy Broth containing 0.5 % yeast extract (TSBY) and adding catechin (1.9, 1.0, 0.75, 0.5 and 0.25 g/l), cultured at 37℃ for 48 hours anaerobically, and measured for minimal inhibitory concentration (MIC). In addition, each bacterial strain was dropped into 1.9 g/l solution; the morphological changes of each bacterium after 1 and 3 hours were observed under SEM and TEM with negative staining to ascertain the influence on oral bacteria of catechin. Results: Neither bacterial strains were grown with the 1.9 g/l culture medium. The MICs were found to be 1.9 g/l against S. mutans and 0.25 g/l against S. sanguinis. In the presence of catechin, the number of bacterial strains was decreased after 1 and 3 hours. Judging from the SEM and the TEM of both bacterial morphology, the bacterial strains appeared to reduce the number of bacterial cells and to change in form when dropped into 1.9 g/l solution. Conclusion: Catechin was found to have an antibacterial effect on oral bacteria. This finding suggests the usefulness of catechin for oral health care and the prevention of local and systemic disease.