Candidacidal Activity of Xylitol and Sorbitol

Purpose: It has been reported that xylitol and sorbitol affect antifungal activities by enhancing antimicrobial activities of other substances. The purpose of this study was to investigate the direct candidacidal activities of xylitol and sorbitol at a wide range of concentration. Methods: Xylitol and sorbitol solubilized with simulated salivary buffer at a range of $0.8{\mu}M$ to 1.05 M were used. Candida albicans strains, ATCC strains 10231, 11006, and 18804 were used for the candidacidal assay. The candidacidal activities of xylitol and sorbitol were determined by comparing the numbers of colony forming units between in the presence and absence of xylitol or sorbitol and calculating the percent loss of cell viability. Results: There were some differences in the candidacidal activities according to the types of sugar alcohols and C. albicans strains. The candidacidal activity of more than 10% was observed when a final concentration of 32.9 mM in xylitol or sorbitol was maintained and that of about 20% was observed when a final concentration of 131 mM was maintained. Even at a high concentration of 1.05 M, the candidacidal activity of xylitol or sorbitol was about 20%. Conclusions: Xylitol and sorbitol at the concentrations used in commercial oral health care products had some levels of candidacidal activities.