Antimicrobial Activity of Traditional Chinese Medicine On Oral Bacteria

Objective: To evaluate a group of twenty Traditional Chinese Medicines (TCM) for their antimicrobial activity against four common oral bacteria. Methods: Twenty TCM were tested for sensitivity against four common oral bacteria Streptococcus mitis, Streptococcus sanguis, Streptococcus mutans and Porphyromonas gingivalis using the standard agar diffusion assay: Aliquots of suspension of each bacterial species were inoculated on a horse blood agar (HBA) plate using a glass rod and afterwards, 6mm 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 at 37ºC. Afterwards, naked eye evaluation of evidences of growth inhibition zone measured. The diameters of growth inhibition of three different areas were measured using a calibrated computer software and the mean diameter obtained for each bacteria. The experiment was repeated on three separate occasions. Results: Nine of the twenty drugs demonstrated consistent antimicrobial activity against Porphyromonas gingivalis, including Folium artemisiae argyi, Fructus crataegi, Rhizoma dryopteris crassirhizomae, Flos magnoliae, Rhizoma polygoni cuspidati, Radix scrophulariae ningpoensis, Galla chinensis, Radix scutellariae baicalensis and Rhizoma coptidis. Both Radix scutellariae baicalensis and Rhizoma coptidis show a greater antimicrobial effect than control against Porphyromonas gingivalis. Fructus crataegi, Galla chinensis and Rhizoma copitidis showed consistent antimicrobial activities against Streptococcus mutans, while Galla chinensis and Rhizoma copitidis are effective against Streptococcus mitis and Streptococcus sanguis. Galla chinensis shows a larger antimicrobial effect than control against Streptococcus sanguis. Conclusion: Both Rhizoma copitidis and Galla chinensis had inhibitory effects on Streptococcus mitis, Streptococcus sanguis, Streptococcus mutans and Porphyromonas gingivalis in vitro.