J Korean Acad Oral Health.  2018 Mar;42(1):9-15. 10.11149/jkaoh.2018.42.1.9.

Inhibitory effect of 18β-glycyrrhetinic acid on the biofilm formation of Streptococcus mutans

  • 1LG Household & Health Care Ltd., Daejeon, Korea. shleek@lgcare.com


The present study aimed at investigating the potential of using 18β-glycyrrhetinic acid against the cariogenic characteristics of Streptococcus mutans UA159.
The effects of 18β-glycyrrhetinic acid on biofilm formation and acid production were evaluated; the latter are indicators of cariogenicity of S. mutans. Biofilm architecture was also analyzed by scanning electron microscopy (SEM), and changes in gene expression related to biofilm formation were studied by quantitative RT-PCR.
Treatment with 18β-glycyrrhetinic acid at a concentration of 20 µg/ml inhibited biofilm formation by 95% in the absence of sucrose and 60% in its presence, reduced acid production by 88.8%, and significantly suppressed the gene expression of comDE, gbpB, gtfC and vicR, which are thought to be involved in the virulence of S. mutans.
These results suggest that 18β-glycyrrhetinic acid could be used as a complementary or alternative agent for preventing dental caries by interfering with the virulence properties of S. mutans without affecting the viability of the bacterial population.


18β-glycyrrhetinic acid; Biofilm inhibition; S. mutans; Dental caries

MeSH Terms

Dental Caries
Gene Expression
Microscopy, Electron, Scanning
Streptococcus mutans*


  • Fig. 1. Effect of 18b-glycyrrhetinic acid on growth of S. mutans. S. mutans incubated with present and absent of 20 μg/ml 18β-glycyrrhetinic acid in a 96well plate at 37°C.

  • Fig. 2. Inhibitory effect of 18β-glycyrrhetinic acid on the biofilm formation by S. mutans in the absence (sucrose-independent) and presence of 1% sucrose (sucrose-dependent). *Significant inhibition compared with untreated control (P<0.05).

  • Fig. 3. SEM images of S. mutans biofilm formed in the presence and absence of the 18β-glycyrrhetinic acid after at 37°C overnight incubation. (A) control, (B) 18β-glycyrrhetinic acid.

  • Fig. 4. Effect of 18β-glycyrrhetinic acid on the biofilm related genes expression of S. mutans. *Significant inhibition compared with untreated control (P<0.05).



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