Antimicrobial activity of traditional Chinese medicines on common oral bacteria

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