Abstract:

Objective To investigate the effects of chloroform extracts of Longdan xiegan decoction (CELX) against hyphae formation of Candida albicans clinical strains isolated from Vulvovaginal Candidiasis (VVC).Methods Microdilution method was used to determine the minimal inhibitory concentrations (MICs) of Longdan xiegan decoction extracts against C. albicans isolated from VVC. Solid agar and Semi-solid agar were utilized to evaluate colony morphology and invasive growth of C. albicans,respectively.XTT and Fluorescence microscope assay were applied to determine the metabolic activity of hyphae of C. albicans treated by CELX for 6 h.Plate assay counted CFU variation.Quantitative Real-time PCR (qRT PCR) was adopted to analyze the expression of hyphae-specific genes including ALS3,SSA1,SUN41,HWP1,UME6 and ECE1.Results The MICs of CELX against C. albicans strains were between 32 and 64 mg/L,which were better than MICs of total extract,petroleum ether extract,ethyl acetate extract,buty alcohol extract and water extract.CELX with concentration of 256 mg/L inhibited hyphae formation and influenced colony morphology significantly,with the wrinkle in solid agar and invasion in semi-solid agar being blocked.The expression of hyphae formation related genes,ALS3,SSA1,SUN41,HWP1,UME6 and ECE1 were down-regulated by 81.6%,60.2%,69.8%,73.7%,49.5%,52.8%.Conclusion Our results suggested that CELX could inhibit hyphae formation through repress hyphae-relative genes expression to reduce the invasive activity against patient.

Key words: Longdan xiegan decoction, Candida albicans, vulvovaginal candidasis (VVC), hyphae