Effects of undecylenic acid released from denture liner on Candida albicans or Candida glabrata biofilms

Author(s)

Letícia Machado Gonçalves

• Document type: Master's Dissertation
• Press: Piracicaba, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Odontologia de Piracicaba
• Defense date: 2012-05-18

Examining board members

Wander José da Silva; Fernanda Faot; Carlos Eduardo Vergani

• Advisor: Wander José da Silva

Abstract

After exposure to oral cavity, denture liners exhibit structural alterations which facilitate colonization by Candida species. In this context, undecylenic acid (UDA) has been incorporated into denture liner formulation in an attempt to reduce the development of fungal biofilms. However, released concentrations of UDA from denture liner and its effects on Candida biofilms have not yet been elucidated. Therefore, the purpose of this study was to investigate the UDA-released concentrations from denture liner and evaluate its effects on C. albicans or C. glabrata biofilms development. Initially, it was simulated, in vitro, the UDA-releasing at oral cavity by immersing specimens of denture liner (10 mm x 2 mm) in artificial saliva, and the released product was quantified by gas chromatography. Then, susceptibility tests of a reference strain and two clinical isolates of C. albicans (ATCC 90028, P01 and P34) and C. glabrata (ATCC 2001, P11 and P31) for UDA were performed by minimal inhibitory concentration (MIC), minimal fungicidal concentration (MFC) and time-kill assays. For evaluate the effects of UDA-released on Candida biofilms, specimens of denture liner containing UDA (experimental group) or not (control group) were saliva-coated and then, biofilms of mentioned strains were developed on such surfaces. At adhesion phase, 24, 48 and 72 h, developed biofilms had their cells counts analyzed by serial dilution; metabolic activity by XTT reduction assay; biofilm structure by confocal laser microscopy; and enzymatic activity of proteinases and phospholipases by colorimetric methods. Data were subjected by analysis of variance followed by Tukey test with a significance level of 5%. UDA-released concentrations from denture liner were within the ranges of MIC and MFC for all strains evaluated. Time-kill results demonstrated that UDA at MIC had a fungistatic behavior for at least 8 hours of exposition for all strains investigated. The presence of UDA did not alter the cell counting, metabolic activity, biofilm structure and enzymatic secretion in the early stages of colonization (adhesion and 24 h) for both species investigated (p > 0.05). At UDA exposure, mature biofilms (48 and 72 h) of C. albicans presented lower cell counts (p < 0.05) and metabolic activity (p = 0.001), although structural changes and enzymatic secretion were not identified (p > 0.05). In contrast, C. glabrata mature biofilms showed higher cell counts (p = 0.004), metabolic status (p < 0.001) and also high secretion of proteinases in the experimental group (p < 0.001). Within the limitations of this study, it could be concluded that UDA-released from DL did not avoid Candida biofilms colonization (AU)

• FAPESP's process: 10/12270-4 - Action of undecylenic acid released from denture liners on bioactivity, bioarchiteture and virulence factors of Candida albicans e Candida glabrata biofilms
• Grantee: Letícia Machado Gonçalves
• Support Opportunities: Scholarships in Brazil - Master