Antibacterial Activity of Curcumin Against Periodontopathic Bacteria

Background: Curcumin is a polyphenol extracted from root of turmeric and known to possess multifunctional properties, including antibacterial activity. Although previous studies have investigated the effects of curcumin on microorganisms, available knowledge on the effects of curcumin on periodontopathic bacteria is still limited. In this study, the antibacterial effect of curcumin on periodontopathic bacteria is investigated, particularly Porphyromonas gingivalis. Methods: Representative periodontopathic bacteria were cultured in media with and without various curcumin concentrations, and the optical density at 600 nm was measured for 60 hours. The inhibitory effect of curcumin on P. gingivalis Arg‐ and Lys‐specific proteinase (RGP and KGP, respectively) activities were assessed using spectrofluorophotometric assay. Analysis of biofilm formation by P. gingivalis with or without Streptococcus gordonii was conducted using confocal laser‐scanning microscopy (CLSM). Results: Curcumin inhibited the growth of P. gingivalis, Prevotella intermedia, Fusobacterium nucleatum, and Treponema denticola in a dose‐dependent manner. Bacterial growth was suppressed almost completely at very low concentrations of curcumin. Conversely, 100 μg/mL curcumin did not suppress the growth of Aggregatibacter actinomycetemcomitans. It also demonstrated inhibitory effects against RGP and KGP activities in a dose‐dependent manner. CLSM revealed that curcumin suppressed P. gingivalis homotypic and P. gingivalis–S. gordonii heterotypic biofilm formation in a dose‐dependent manner. A concentration of 20 μg/mL curcumin inhibited these P. gingivalis biofilm formations by >80%. Conclusion: Curcumin possesses antibacterial activity against periodontopathic bacteria and may be a potent agent for preventing periodontal diseases.