Choong-Ho Choi

Inhibitory effect of methyl gallate and gallic acid on oral bacteria

This study examined the ability of methyl gallate (MG) and gallic acid (GA), the main compounds of gallo-tannins in Galla Rhois, to inhibit the proliferation of oral bacterial and the in vitro formation of Streptococcus mutans biofilms. The antimicrobial activities of these compounds were evaluated in vitro using the broth microdilution method and a beaker-wire test. Both MG and GA had inhibitory effects on the growth of cariogenic (MIC<8 mg/ml) and periodontopathic bacteria (MIC=1 mg/ml). Moreover, these compounds significantly inhibited the in vitro formation of S. mutans biofilms (MG, 1 mg/ml; GA, 4 mg/ml; P<0.05). MG was more effective in inhibiting bacterial growth and the formation of S. mutans biofilm than GA. In conclusion, MG and GA can inhibit the growth of oral pathogens and S. mutans biofilm formation, and may be used to prevent the formation of oral biofilms.

Anti-cariogenic effects of erythritol on growth and adhesion of Streptococcus mutans

Erythritol is one of the most widely used low calorie sugar substitutes and has known inhibitory effects on the growth of Streptococcus mutans. However, the mechanism underlying this inhibition is poorly understood. Expression profiles of the glucosyltransferase (GTF) and fructosyltransferase (FTF) genes in S. mutans were evaluated in the presence of erythritol and other sweeteners. Adhesion of S. mutans to different carbohydrates was also determined across a range of concentrations. Erythritol significantly (p<0.05) inhibited adherence of S. mutans under multiple conditions, compared with sucrose. Erythritol significantly (p<0.05) inhibited expressions of gtfB, gtfC, gtfD, and ftf in the presence of various carbohydrates compared with sucrose. These findings were consistent with an anti-cariogenic effect of erythritol on S. mutans, and suggested mechanisms by which erythritol inhibits formation of dental caries.

Anti-inflammatory effects of bamboo salt and sodium fluoride in human gingival fibroblasts–An in vitro study

Dental caries preventive agents, such as sodium fluoride (NaF) and bamboo salt (BS), are known to cause cellular growth that is characterized by morphological and gene expression changes. This study was designed to investigate the dual effect of NaF and BS on interleukin (IL)‐1β‐induced gingival inflammation. Under in vitro experimental conditions, exposure to a subcytotoxic dose of IL‐1β enhanced human gingival fibroblast inflammation, as characterized by increased levels of inflammation‐associated proteins. A combination of NaF and BS significantly protected fibroblasts from IL‐1β‐induced cellular deterioration. Exposure to NaF and BS induced the cell growth and no changes in viability were found with the Lactate Dehydrogenase Assay (LDH) assay at the NaF and BS concentration analyzed. Molecular analysis demonstrated that NaF and BS increased resistance to inflammation by reduction of IL‐1β, IL‐8, and tumor necrosis factor (TNF)‐α production. In addition, NaF and BS decreased the expression of IL‐1β, IL‐8, and TNF‐α mRNA in IL‐1β‐induced human gingival fibroblast cells. The study identifies a new role for NaF and BS in the IL‐1β‐induced inflammation of gingival fibroblasts and provides a potential target for gingival protection.