Antimicrobial Activity of Traditional Chinese Medicines on Common Oral Bacteria

Michelle K Z Yuen,Urban Hägg,Ricky W K Wong,Lakshman Samaranayake

doi:10.4236/cm.2011.22007

Abstract

Objective: To evaluate twenty Traditional Chinese Medicines (TCM) against four oral bacteria. Methods: Twenty TCM were tested for sensitivity against Streptococcus mitis, Streptococcus sanguis, Streptococcus mutans and Porphyromonas gingivalis. Aliquots of suspension of each bacterial species were inoculated on a horse blood agar (HBA) plate, 6 mm diameter paper disks was soaked in different drug suspensions were placed concentrically on a HBA plate. Disks soaked in 0.2% w/v chlorhexidine were used as positive controls. These HBA plates were incubated for 48 hours anaerobically and the diameters of growth inhibition of three different areas were measured using a calibrated computer software and the mean diameter obtained for each bacteria. Broth microdilution assay was used to determine minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). The experiment was repeated on three separate occasions. Results: The TCMs that consistently against Porphyromonas gingivalis, included Folium artemisiae argyi, Fructus crataegi, Rhizoma dryopteris crassirhizomae, Flos magnoliae, Rhizoma polygoni cuspidati, Radix scrophulariae ningpoensis, Galla chinensis, Radix scutellariae baicalensis and Rhizoma coptidis; against Streptococcus mutans included Fructus crataegi, Galla chinensis and Rhizoma copitidis; against Streptococcus mitis and Streptococcus sanguis included Galla chinensis and Rhizoma copitidis. Conclusion: Rhizoma copitidis and Galla chinensis had inhibitory effects on Streptococcus mitis, Streptococcus sanguis, Streptococcus mutans and Porphyromonas gingivalis in vitro.

Highlights

Dental caries is a common human disease that affects a vast majority of people
The mean of inhibition zones of chlorhexidine measured were 7.4 mm against Streptococcus mitis compared to Galla chinensis and Rhizoma copitidis, which were of 5.8 mm and 6.2 mm respectively (Table 1, Figures 1 and 2)
The average mean of inhibition zone measured in diameter of chlorhexidine was 9.1 mm against Streptococcus sanguis, where as Galla chinensis and Rhizoma copitidis were measured as 10.6 mm and 7.6 mm

Summary

Introduction

Dental caries is a common human disease that affects a vast majority of people. It is a chronic endogenous infection caused by the normal oral commensal flora [1]. Oral biofilm develop on all natural or artificial shedding and non-shedding surfaces of the oral cavity. Microorganisms in oral biofilm are the major aetiological agents of dental caries. Oral biofilm can cause many oral infections including periodontal disease and candidiasis. The “pioneer species” of oral biofilm are Streptococcus oralis, Streptococcus mitis and Streptococcus sanguis. There are specific bacteria that are closely related to specific dental diseases, for example, Stre ptococcus mutans and Porphyromonas gingivalis are associated with dental caries and periodontal disease, respectively [1]

Methods

Results

Conclusion