D-Tagatose Effectively Reduces the Number of Streptococcus mutans and Oral Bacteria in Healthy Adult Subjects: A Chewing Gum Pilot Study and Randomized Clinical Trial.

We examined the effect of D-Tagatose on the growth of oral bacteria including Streptococcus mutans (S. mutans). Saliva collected from 10 healthy volunteers was plated on BHI medium (to culture total oral bacteria) and MBS medium (to culture S. mutans, specifically). Agar plates of BHI or MBS containing xylitol or D-Tagatose were cultured under aerobic or anaerobic conditions. We then counted the number of colonies. In BHI plates containing D-Tagatose, a complete and significant reduction of bacteria occurred under both aerobic and anaerobic conditions. In MSB medium, significant reduction of S. mutans was also observed. We then performed a doubleblind parallel randomized trial with 19 healthy volunteers. They chewed gum containing xylitol, D-Tagatose, or both for 4 weeks, and their saliva was collected weekly and plated on BHI and MSB media. These plates were cultured under anaerobic conditions. Total bacteria and S. mutans were not effectively reduced in either the D-Tagatose or xylitol gum group. However, S. mutans was significantly reduced in volunteers chewing gum containing both D-Tagatose and xylitol. Thus, D-Tagatose inhibited the growth of S. mutans and many types of oral bacteria, indicating that D-Tagatose intake may help prevent dental caries, periodontitis, and many oral diseases.

D­Tagatose inhibits the growth and biofilm formation of Streptococcus mutans.

Dental caries is an important global health concern and Streptococcus mutans has been established as a major cariogenic bacterial species. Reports indicate that a rare sugar, D­tagatose, is not easily catabolized by pathogenic bacteria. In the present study, the inhibitory effects of D­tagatose on the growth and biofilm formation of S. mutans GS­5 were examined. Monitoring S. mutans growth over a 24 h period revealed that D­tagatose prolonged the lag phase without interfering with the final cell yield. This growth retardation was also observed in the presence of 1% sucrose, although it was abolished by the addition of D­fructose. S. mutans biofilm formation was significantly inhibited by growth in sucrose media supplemented with 1 and 4% D­tagatose compared with that in a culture containing sucrose alone, while S. mutans formed granular biofilms in the presence of this rare sugar. The inhibitory effect of D­tagatose on S. mutans biofilm formation was significantly more evident than that of xylitol. Growth in sucrose media supplemented with D­tagatose significantly decreased the expression of glucosyltransferase, exo­ß­fructosidase and D­fructose­specific phosphotransferase genes but not the expression of fructosyltransferase compared with the culture containing sucrose only. The activity of cell­associated glucosyltransferase in S. mutans was inhibited by 4% D­tagatose. These results indicate that D­tagatose reduces water­insoluble glucan production from sucrose by inhibiting glucosyltransferase activities, which limits access to the free D­fructose released during this process and retards the growth of S. mutans. Therefore, foods and oral care products containing D­tagatose are anticipated to reduce the risk of caries by inhibiting S. mutans biofilm formation.

Cleansing effect of acidic L-arginine on human oral biofilm.

BACKGROUND: Dental plaque formed on tooth surfaces is a complex ecosystem composed of diverse oral bacteria and salivary components. Accumulation of dental plaque is a risk factor for dental caries and periodontal diseases. L-arginine has been reported to decrease the risk for dental caries by elevating plaque pH through the activity of arginine deiminase in oral bacteria. Here we evaluated the potential of L-arginine to remove established oral biofilms. METHODS: Biofilms were formed using human saliva mixed with Brain Heart Infusion broth supplemented with 1 % sucrose in multi-well plates or on plastic discs. After washing the biofilms with saline, citrate (10 mM, pH3.5), or L-arginine (0.5 M, pH3.5), the retained biofilms were analyzed by crystal violet staining, scanning electron microscopy, and Illumina-based 16S rDNA sequencing. RESULTS: Washing with acidic L-arginine detached oral biofilms more efficiently than saline and significantly reduced biofilm mass retained in multi-well plates or on plastic discs. Illumina-based microbiota analysis showed that citrate (pH3.5) preferentially washed out Streptococcus from mature oral biofilm, whereas acidic L-arginine prepared with 10 mM citrate buffer (pH3.5) non-specifically removed microbial components of the oral biofilm. CONCLUSIONS: Acidic L-arginine prepared with citrate buffer (pH3.5) effectively destabilized and removed mature oral biofilms. The acidic L-arginine solution described here could be used as an additive that enhances the efficacy of mouth rinses used in oral hygiene.