Chlorhexidine: beta-cyclodextrin inhibits yeast growth by extraction of ergosterol
Braz. j. microbiol
;
43(2): 810-818, Apr.-June 2012. ilus, graf, tab
Artigo
em Inglês
| LILACS
| ID: lil-644500
ABSTRACT
Chlorhexidine (Cx) augmented with beta-cyclodextrin (β-cd) inclusion compounds, termed Cx:β-cd complexes, have been developed for use as antiseptic agents. The aim of this study was to examine the interactions of Cx:β-cd complexes, prepared at different molecular ratios, with sterol and yeast membranes. The Minimal Inhibitory Concentration (MIC) against the yeast Candida albicans (C.a.) was determined for each complex; the MICs were found to range from 0.5 to 2 µg/mL. To confirm the MIC data, quantitative analysis of viable cells was performed using trypan blue staining. Mechanistic characterization of the interactions that the Cx:β-cd complexes have with the yeast membrane and assessment of membrane morphology following exposure to Cx:β-cd complexes were performed using Sterol Quantification Method analysis (SQM) and scanning electron microscopy (SEM). SQM revealed that sterol extraction increased with increasing β-cd concentrations (1.71 × 10³; 1.4 × 10³; 3.45 × 10³, and 3.74 × 10³ CFU for 1:1, 1:2, 1:3, and 1:4, respectively), likely as a consequence of membrane ergosterol solubilization. SEM images demonstrated that cell membrane damage is a visible and significant mechanism that contributes to the antimicrobial effects of Cx:β-cd complexes. Cell disorganization increased significantly as the proportion of β-cyclodextrin present in the complex increased. Morphology of cells exposed to complexes with 1:3 and 1:4 molar ratios of Cx:β-cd were observed to have large aggregates mixed with yeast remains, representing more membrane disruption than that observed in cells treated with Cx alone. In conclusion, nanoaggregates of Cx:β-cd complexes block yeast growth via ergosterol extraction, permeabilizing the membrane by creating cluster-like structures within the cell membrane, possibly due to high amounts of hydrogen bonding.
Texto completo:
DisponíveL
Índice:
LILACS (Américas)
Assunto principal:
Leveduras
/
Candida albicans
/
Corpos de Inclusão
/
Clorexidina
/
Beta-Ciclodextrinas
/
Ergosterol
/
Anti-Infecciosos Locais
Idioma:
Inglês
Revista:
Braz. j. microbiol
Assunto da revista:
Microbiologia
Ano de publicação:
2012
Tipo de documento:
Artigo
País de afiliação:
Brasil
Instituição/País de afiliação:
Universidade Federal de Minas Gerais/BR
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