In Vitro Effects of Zinc Compounds on the Candidacidal Activities of Salivary Antimicrobials

This study aimed to investigate the effects of zinc compounds on the candidacidal activities of lysozyme and the peroxidase (PO) and glucose oxidase-mediated peroxidase (GO-PO) systems against Candida albicans.

Four zinc compounds were used: zinc chloride, gluconate, lactate, and sulphate. Three antimicrobial systems were used: hen egg-white lysozyme (HEWL), the PO system [bovine lactoperoxidase (bLPO), potassium thiocyanate, and hydrogen peroxide], and the GO-PO system (bLPO, potassium thiocyanate, glucose oxidase, and glucose). Three Candida albicans strains were used: ATCC 10231, 11006, and 18804. The candidacidal activity of each zinc compound-antimicrobial system mixture was compared with that of the zinc compound or antimicrobial system alone.

The addition of zinc chloride and gluconate significantly (P < .05) increased the candidacidal activity of HEWL in the ATCC 10231 and 11006 strains. Regarding the PO system, the addition of zinc sulphate in the ATCC 10231 strain and of zinc chloride or gluconate in the ATCC 18804 strain significantly (P < .05) increased the candidacidal activity compared with the PO system alone. No significant changes were observed in the candidacidal activities of the mixture of each zinc compound and the GO-PO system compared with the GO-PO system alone for all three C. albicans strains.

Although it depended on the type of zinc compound or strain, the addition of zinc compounds increased the candidacidal activities of antimicrobial enzymes against C. albicans compared with HEWL or the PO system alone. The introduction of zinc compounds into oral healthcare products containing antimicrobials could provide additional antifungal activity.