Antifungal Activity Of Sodium Houttuyfonate Against Candida Albicans And Study Of Its Mechanism

Objective To investigate the anti-fungal activity of SH (Sodium Houttuyfonate) against candida albicans and explore the mechanism under this activity. To find effective antifungal drugs with noval chemical constructions and new targets.Methods First we adoptted Broth microdilution analysis to determine MIC80of SH against about20C.albicans strains. Next we confirmed its antifungal activity by growth curve, time-kill curve and systemic fungal infection assay in mice. XTT reduction assay, laser scanning confocal microscope(LSCM) of biofilm and cell surface hydrophobicity assay was then conducted to determine its activity against C. albicans biofilms. We tried to find out the mechanism by measurment of cell cycle,ROS and permeability of cells treated with or without SH. Transmission Electron Microscope(TEM) and Scanning Electron Microscope(SEM) were applied respectively to observe ultrastructure and surface changes of C.albicans cells before and after treated with SH. Spectrometer (GC/MS) assay were performed to investigate if SH play a role in the ergosterol biosynthetic pathway. Finally, real-time RT-PCR assays were applied to determine the gene expression changes after SH treatment.Results Broth microdilution analysis showed that SH possessed good activities against almost all C. albicans isolates tested,with a MIC80ranged from8μg/ml to16μg/ml.growth curves showed that SH had weak activity against candida albicans in YPD,while time-kill curves showed a stong effect in RPMI1640. Systemic fungal infection in mice indicated that SH was effective in vivo although it had some slide effect in high dose.SH played an anti-biofilm effect during biofilm development and CSH decreased sharply as SH concentration was raised. Ultrastructure analysis by TEM revealed a membrane damage while SEM of biofilm showed cytoplasm leakage induced by SH.Subsequently cell permeability was proved to be changed by SH. Real-time RT-PCR analytic results showed that SH treatment resulted in remarkable change in some biofilm adherence and drug resistance-related genes.Coclusions Our present study showed that SH exhibted aitifungal activity probably by causing membrane damages which lead to cytoplasm leakage.