(The) effects of xylitol and sorbitol on the enzymatic and candidacidal activities related with lysozyme and peroxidase

Abstract

The purpose of this study was to investigate what xylitol and sorbitol could affect on the enzymatic and candidacidal activities of lysozyme, the peroxidase system, and the glucose oxidase-mediated peroxidase system. Xylitol and sorbitol were added to hen egg-white lysozyme, bovine lactoperoxidase, glucose oxidase-mediated peroxidase, and whole saliva in solution and on the hydroxyapatite surface phases. The enzymatic activities of lysozyme, peroxidase, and glucose oxidase-mediated peroxidase were determined by measuring the turbidity of a Micrococcus lysodeikticus suspension, the rate of oxidation to 5,5-dithiobis-2-nitrobenzoic acid by hypothiocyanite, and the production of oxidized o-dianisidine, respectively. Candidacidal activities were determined by comparing colony forming units and calculating the percent loss of cell viability using Candida albicans ATCC 10231, 11006, and 18804. Both xylitol and sorbitol did not affect the enzymatic activity of hen egg-white lysozyme both in solution and on the hydroxyapatite surface phases, while both sugar alcohols inhibited the enzymatic activity of salivary lysozyme significantly in solution phase, but not on the surface phase. Both xylitol and sorbitol enhanced the enzymatic activities of both bovine lactoperoxidase and salivary peroxidase significantly by dose-dependent manner in solution phase, but not on the surface phase. Sorbitol, not xylitol, inhibited the enzymatic activity of glucose oxidase-mediated peroxidase significantly. Both xylitol and sorbitol did not affect the candidacidal activities of hen egg-white lysozyme, the bovine lactoperoxidase system, and the glucose oxidase-mediated bovine lactoperoxidase system. Conclusively, xylitol and sorbitol inhibited salivary lysozyme activity, but enhanced both bovine lactoperoxidase and salivary peroxidase activities significantly in solution phase. Xylitol and sorbitol were not additive to the candidacidal activities related with lysozyme and peroxidase.