title: The antimicrobial effects of deglycyrrhizinated licorice root extract on Streptococcus mutans UA159 in both planktonic and biofilm cultures.
abstract: The objective of the study was to investigate the antimicrobial effects of deglycyrrhizinated licorice root extracts (DG-LRE) against Streptococcus mutans UA159 in both the planktonic and biofilm phases by determining the minimum inhibitory concentration and minimum bactericidal concentration, and by performing time-kill kinetic, growth, adhesion, and biofilm assays. The cell toxicity of DG-LRE on normal human gingival fibroblast (NHGF) cells was tested using a methyl thiazolyl tetrazolium assay. This study showed that DG-LRE had strong antimicrobial activity against S. mutans in the planktonic phase with little cytotoxic effect on NHGF cells. In addition, DG-LRE significantly inhibited biofilm formation by S. mutans UA159 at concentrations over 4 μg/ml for glucose or 16 μg/ml for sucrose, respectively, regardless of the presence of saliva-coating. To the best of our knowledge, this is the first report to provide evidence that DG-LRE demonstrates antimicrobial activity against S. mutans. These results suggest that DG-LRE can be used in developing oral hygiene products, such as gargling solution and dentifrice to prevent human dental caries.
authors.affiliation: Dental Research Institute and Department of Orthodontics, School of Dentistry, Seoul National University, 28-22 Yungeon-Dong, Jongro-Gu, Seoul 110-768, Republic of Korea.
authors.forename: Sug-Joon
authors.initials: SJ
authors.lastname: Ahn
authors.forename: Eun-Jung
authors.initials: EJ
authors.lastname: Cho
authors.forename: Hyoung-Jun
authors.initials: HJ
authors.lastname: Kim
authors.forename: Soon-Nang
authors.initials: SN
authors.lastname: Park
authors.forename: Yun-Kyong
authors.initials: YK
authors.lastname: Lim
authors.forename: Joong-Ki
authors.initials: JK
authors.lastname: Kook
mesh_terms: D000900:Anti-Bacterial Agents / Q000302:isolation & purification / Q000494:pharmacology* / Q000633:toxicity; D018441:Biofilms / Q000187:drug effects*; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D005347:Fibroblasts / Q000187:drug effects; D006035:Glycyrrhiza / Q000737:chemistry*; D006801:Humans; D008826:Microbial Sensitivity Tests; D050296:Microbial Viability / Q000187:drug effects; D010936:Plant Extracts / Q000302:isolation & purification / Q000494:pharmacology* / Q000633:toxicity; D018517:Plant Roots / Q000737:chemistry*; D013295:Streptococcus mutans / Q000187:drug effects* / Q000502:physiology
chemical_list: D000900:Anti-Bacterial Agents; D010936:Plant Extracts