Microbiological evaluation of an experimental denture cleanser containing essential oil of Lippia sidoides

Abstract

The antimicrobial activity of an experimental solution containing essential oil of Lippia sidoides for denture cleaning was evaluated by (1) minimum inhibitory (MIC) and fungicidal/bactericidal concentration (MFC/MBC) tests against Candida albicans, Staphylococcus aureus, and Pseudomona aeruginosa; (2) the metabolic activity of C. albicans biofilm formed on flat-bottom microplates and denture base specimens based on the reduction of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT); and (3) scanning electron microscopy, to evaluate the fungal biofilm morphology. The solution showed antimicrobial action against the pathogens tested (C. albicans - MIC and MFC: 19.53 µg ml^-1, S. aureus - MIC and MBC: 78.12 µg ml^-1, P. aeruginosa - MIC: 625 µg ml^-1, MBC: 2,500 µg ml^-1), reduced the metabolic activity of C. albicans biofilm up to 97%, and caused cell wall damage at low concentrations (195.3-390.6 µg ml^-1) and in short time periods (20 min). Therefore, the experimental solution has the potential to be used as an alternative in the prevention and treatment of denture-induced infections.

Keywords: Biofilm; Candida albicans; Lippia; denture cleansers; denture stomatitis.