In vitro antifungal activity of the flavonoid baicalein against Candida species.
The aim of the present study was to evaluate the in vitro activity of baicalein, the flavone constituent of Scutellaria baicalensis, and synergism of the combination of baicalein and fluconazole against Candida albicans, Candida tropicalis and Candida parapsilosis. The MIC(50) (lowest concentration at which there was 50 % inhibition of growth) of baicalein alone against six Candida strains ranged from 13 to 104 µg ml(-1). For the three species tested, exposure to baicalein at the MIC(50) concentrations obtained for each strain resulted in a high loss of viability. The fluconazole plus baicalein combination markedly reduced the MICs of both drugs for all three strains analysed. In addition, a synergistic effect between baicalein and fluconazole was observed for C. parapsilosis in terms of MIC(50) (fractional inhibitory concentration index = 0.207). Scanning electron microscopy analysis revealed that yeast cells exposed to baicalein at MIC(50) produced a profusely flocculent extracellular material, resembling a biofilm-like structure. In conclusion, these results showed the antifungal capability of baicalein against Candida species and highlight a promising role of baicalein when used in combination with fluconazole against Candida infections.
Department of Microbiology, Paraná State University at Londrina, C. P. 6001, 86051990, Brazil.
Rosana
R
Serpa
Department of Microbiology, Paraná State University at Londrina, C. P. 6001, 86051990, Brazil.
Emanuele J G
EJG
França
Technological Federal University of Paraná, Brazil.
Luciana
L
Furlaneto-Maia
Electronic Microscopy and Microanalysis Laboratory, Paraná State University at Londrina, Brazil.
Célia G T J
CGTJ
Andrade
Department of Pharmacy, Paraná State University at Maringá, Brazil.
Andréa
A
Diniz
Department of Microbiology, Paraná State University at Londrina, C. P. 6001, 86051990, Brazil.
Márcia C
MC
Furlaneto
D000935:Antifungal Agents / Q000494:pharmacology*; D002176:Candida albicans / Q000187:drug effects*; D041022:Candida tropicalis / Q000187:drug effects*; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D044950:Flavanones / Q000737:chemistry / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests
D000935:Antifungal Agents; D004791:Enzyme Inhibitors; D044950:Flavanones; C006680:baicalein