Potential of Prebiotic D-Tagatose for Prevention of Oral Disease

Abstract

Recent studies have shown phenotypic and metabolic heterogeneity in related species including Streptococcus oralis, a typical oral commensal bacterium, Streptococcus mutans, a cariogenic bacterium, and Streptococcus gordonii, which functions as an accessory pathogen in periodontopathic biofilm. In this study, metabolites characteristically contained in the saliva of individuals with good oral hygiene were determined, after which the effects of an identified prebiotic candidate, D-tagatose, on phenotype, gene expression, and metabolic profiles of those three key bacterial species were investigated. Examinations of the saliva metabolome of 18 systemically healthy volunteers identified salivary D-tagatose as associated with lower dental biofilm abundance in the oral cavity (Spearman’s correlation coefficient; r = -0.603, p = 0.008), then the effects of D-tagatose on oral streptococci were analyzed in vitro. In chemically defined medium (CDM) containing D-tagatose as the sole carbohydrate source, S. mutans and S. gordonii each showed negligible biofilm formation, whereas significant biofilms were formed in cultures of S. oralis. Furthermore, even in the presence of glucose, S. mutans and S. gordonii showed growth suppression and decreases in the final viable cell count in a D-tagatose concentration-dependent manner. In contrast, no inhibitory effects of D-tagatose on the growth of S. oralis were observed. To investigate species-specific inhibition by D-tagatose, the metabolomic profiles of D-tagatose-treated S. mutans, S. gordonii, and S. oralis cells were examined. The intracellular amounts of pyruvate-derived amino acids in S. mutans and S. gordonii, but not in S. oralis, such as branched-chain amino acids and alanine, tended to decrease in the presence of D-tagatose. This phenomenon indicates that D-tagatose inhibits growth of those bacteria by affecting glycolysis and its downstream metabolism. In conclusion, the present study provides evidence that D-tagatose is abundant in saliva of individuals with good oral health. Additionally, experimental results demonstrated that D-tagatose selectively inhibits growth of the oral pathogens S. mutans and S. gordonii. In contrast, the oral commensal S. oralis seemed to be negligibly affected, thus highlighting the potential of administration of D-tagatose as an oral prebiotic for its ability to manipulate the metabolism of those targeted oral streptococci.

Polymicrobial Infections and Biofilms: Clinical Significance and Eradication Strategies

“…The decreased pH and demineralization of dental tissues lead to the attachment of pathogens to the enamel and cause dental caries [ 50 ]. The acid produced by biofilms damage teeth enamel and lead to the cavitation and destruction of teeth [ 51 ]. Approximately 60–90% incidence of dental caries is observed in underprivileged children due to the acid produced by S. mutans biofilms.…”

How probiotics, prebiotics, synbiotics, and postbiotics prevent dental caries: an oral microbiota perspective

“…D-tagatose, a non-cariogenic sugar, is a potential prebiotic that offers lower calories and a lower glycemic index than sucrose 137 . Notably, the saliva of individuals with good oral health is rich in D-tagatose 138 . D-tagatose may inhibit the growth of S. mutans and S. gordonii by affecting glycolysis and its downstream metabolism, but it does not affect S. oralis 138 .…”

“…Notably, the saliva of individuals with good oral health is rich in D-tagatose 138 . D-tagatose may inhibit the growth of S. mutans and S. gordonii by affecting glycolysis and its downstream metabolism, but it does not affect S. oralis 138 . Encouragingly, chewing gum containing D-tagatose has been shown to inhibit the growth of S. mutans 139 .…”

Streptococcus gordonii: An updated review

“…It is suggested that BAR-encapsulated NPs provide a potent platform to inhibit (prevent) and disrupt (treat) P. gingivalis/S.gordonii biofilms, relative to free BAR [15] . Experimental results demonstrated that D-tagatose found in saliva selectively inhibits the growth of oral pathogens S. mutans and S. gordonii [16] . Similarly, SCFA could be an effective anti-biofilm agent against S. gordonii for the prevention of oral diseases [17] .…”