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BioMed Research International
Volume 2018, Article ID 4508709, 11 pages
Research Article

Curcumin as a Promising Antibacterial Agent: Effects on Metabolism and Biofilm Formation in S. mutans

1Department of Preventive Dentistry, Guanghua School of Stomatology, Sun Yat-sen University, 56 Ling Yuan Road West, Guangzhou 510055, China
2Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou 510055, China

Correspondence should be addressed to Huancai Lin; moc.621@zgchnil and Yan Zhou; moc.361@3.01yuohz

Received 9 November 2017; Revised 16 January 2018; Accepted 29 January 2018; Published 28 February 2018

Academic Editor: Ronald E. Baynes

Copyright © 2018 Bingchun Li et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Streptococcus mutans (S. mutans) has been proved to be the main aetiological factor in dental caries. Curcumin, a natural product, has been shown to exhibit therapeutic antibacterial activity, suggesting that curcumin may be of clinical interest. The objective of this study is to evaluate the inhibitory effects of curcumin on metabolism and biofilm formation in S. mutans using a vitro biofilm model in an artificial oral environment. S. mutans biofilms were treated with varying concentrations of curcumin. The biofilm metabolism and biofilm biomass were assessed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay and the crystal violet assay. Confocal laser scanning microscopy was used to analyse the composition and extracellular polysaccharide content of S. mutans biofilm after curcumin treatment. The biofilm structure was evaluated using a scanning electron microscope. The gene expression of virulence-related factors was assessed by real-time PCR. The antibiofilm effect of curcumin was compared with that of chlorhexidine. The sessile minimum inhibitory concentration (SMIC50%) of curcumin against S. mutans biofilm was 500 μM. Curcumin reduced the biofilm metabolism from 5 min to 24 h. Curcumin inhibited the quantity of live bacteria and total bacteria in both the short term (5 min) and the long term. Moreover, curcumin decreased the production of extracellular polysaccharide in the short term. The expression of genes related to extracellular polysaccharide synthesis, carbohydrate metabolism, adherence, and the two-component transduction system decreased after curcumin treatment. The chlorhexidine-treated group showed similar results. We speculate that curcumin has the capacity to be developed as an alternative agent with the potential to reduce the pathogenic traits of S. mutans biofilm.