Antibacterial activity of quercetin on oral infectious pathogens

The aim of this study was to evaluate the antimicrobial activity of quercetin against pathogens of the main oral infectious diseases which include caries, periodontitis and oral mucosa infectious diseases associated microorganisms. Agar diffusion assay was adopted to observe the effects of quercetin on the growth of 11 main oral pathogenic microorganisms, including Streptococcus mutans, Streptococcus sanguis, Streptococcus sobrinus, Actinomyces viscosus, Actinomyces naeslundii, Lactobacillus acidophilu, Porphyromonas gingivalis, Fusobacterium nucleatum, Actinobacillus actinomycetemocomitans, Prevotella intermedia and Candia albicans. The antibacterial activity of quercetin was determined in form of minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) using agar dilution assay. In all experiments, results obtained indicated that quercetin had inhibitory effects on S. mutans with MIC of 2 mg/ml and MBC of 8 mg/ml, S. sobrinus with MIC of 1 mg/ml and MBC of 8 mg/ml, L. acidophilu with MIC of 2 mg/ml and MBC of 16 mg/ml, S. sanguis with MIC of 2 mg/ml and MBC of 16 mg/ml, A. actinomycetemocomitans with MIC of 1 mg/ml and MBC of 8 mg/ml,P. intermedia with MIC of 4 mg/ml and MBC of 16 mg/ml, respectively. Thus, it could be concluded that quercetin had different antibacterial activities against oral bacteria, in which the quecetin showed better antibacterial effect on caries-related bacteria, and could be encouraged for further development in caries prevention and treatment.   Key words: oral bacteria, quercetin, antibacterial, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC).