Effect of xylitol on salivary β-glucosidase in humans

Dental biofilm - in which a diverse set of microorganisms are embedded in a complex polysaccharide matrix that adheres to oral components - is one of the most complex microbial communities in the human body. As biofilm formation is related to oral infections, such as caries and periodontal diseases, strategies for biofilm control are crucial for maintaining oral health. Xylitol, a synthetic sugar used as a sucrose substitute, has been shown to reduce biofilm formation. However, its precise mechanism of action on biofilm reduction has so far not been elucidated. Previous studies demonstrate that bacterial β-glucosidase action is crucial for biofilm formation. Here, we investigated the correlation between salivary β-glucosidase activity and dental plaque occurrence. We found a positive correlation between enzymatic activity and the presence of dental biofilm. We observed that xylitol inhibits β-glucosidase in human saliva. Kinetic studies also confirmed that xylitol acts as a mixed type inhibitor of salivary β-glucosidase. Based on our data, we suggest that xylitol impairs oral biofilm formation by the inhibition of bacterial β-glucosidase, which is essential for biofilm formation in the oral cavity.