The successful preventing and effective treatment of invasive Candida albicans infections required
research focused on synthesis of new classes of agents and antifungal activity studies. Bromodichloromethyl-
4-chloro-3-nitrophenyl sulfone (named compound 6); dichloromethyl-4-chloro-3-nitrophenyl sulfone
(named 7); and chlorodibromomethyl-4-hydrazino-3-nitrophenyl sulfone (named 11) on inhibition
of planktonic cells’ growth, leucine arylamidase APE2 gene expression, and adhesion to epithelial cells
were investigated. In vitro anti-Candida activities were determined against wild-types, and the morphogenesis
mutants: Defg1 and Dcph1. MICs of compounds 6, 7 and 11 (concentrated at 0.25–16 lg/ml) were
determined using the Clinical and Laboratory Standards Institute Broth Microdilution Method (M27-A3
Document). APE2 expression was analyzed using RT-PCR; relative quantification was normalized against
ACT1 in cells growth in YEPD and on Caco-2 cell line. Adherence assay of C. albicans to Caco-2 was performed
in 24-well-plate.
The structure activity relationship suggested that sulfone containing hydrazine function at C-1 (compound
11) showed higher antifungal activity (cell inhibition% = 100 at 1–16 lg/ml) than the remaining
sulfones with chlorine at C-1. Dcph1/Defg1 was highly sensitive to compound 11, while the sensitivity
was reduced in Dcph1/Defg1::EFG1 (% = 100 at 16-fold higher concentration). Compound 11 significantly
affected adherence to epithelium (P 60.05) and hyphae formation. The APE2 up-regulation plays role in
sulfones’ resistance on MAP kinase pathway. Either CPH1 or EFG1 play a role in the resistance mechanism
in sulfones. The strain-dependent phenomenon is a factor in the sulfone resistance mechanism. Sulfones’
mode of action was attributed to reduced virulence arsenal in terms of adhesiveness and pathogenic
potential related to the APE2 expression and morphogenesis