Dracorhodin perchlorate inhibits biofilm formation and virulence factors of Candida albicans

OBJECTIVE

The aim of this study was to investigate the antifungal activity of dracorhodin perchlorate (DP) against planktonic growth and virulence factors of Candida albicans.

METHODS

Microdilution method based on CLSI-M27-A3 was used to test the antifungal susceptibility of DP. The activity of DP against biofilm formation and development of C. albicans was quantified by XTT assay and visualized by confocal laser scanning microscope. The effect of DP on the morphological transition of C. albicans induced by four kinds of hyphal-inducing media at 37°C for 4hours was observed under microscope. The rescue experiment by adding exogenous cAMP analog was performed to investigate the involvement of cAMP in the yeast to hyphal transition and biofilm formation of C. albicans. Egg yolk emulsion agar was used to determine the inhibition of DP on the phospholipase production of C. albicans. Human JEG-3 and HUVEC cell lines, as well as the nematode Caenorhabditis elegans was used to assess the toxicity of DP.

RESULTS

The minimum inhibitory concentration (MIC) of DP is 64μM while the antifungal activity was fungistatic. As low as a concentration at 16μM, DP could inhibit the yeast to hyphal transition in liquid RPMI-1640, Spider, GlcNAc and 10% FBS-containing Sabouroud Dextrose medium, as well as on the solid spider agar. Exogenous cAMP analog could rescue part of biofilm viability of C. albicans. DP could inhibit the production of phospholipase. The toxicity of DP against human cells and C. elegans is low.

CONCLUSION

DP could inhibit the planktonic growth and virulent factors in multiple stages, such as yeast to hyphal transition, adhesion, biofilm formation and production of phospholipase of C. albicans.

[Recombinant human tumor necrosis factor receptor type Ⅱ-IgG Fc fusion protein for treatment of occupational medicamentosa-like dermatitis induced by trichloroethylene]

Objective: To investigate the efficacy and safety of the recombinant human tumor necrosis factor receptor Ⅱ-IgG Fc fusion protein (rhTNFR: Fc, etanercept) for the treatment of occupational medicamentosa-like dermatitis induced by trichloroethylene (OMLDT) . Methods: In September 2011 to February 2016, 12 patients with OMLDT were treated with etanercept 25 mg, subcutaneous injection, twice per week, doubling of first dose. The course of treatment was 6 weeks. The drug eruption area and severity index (DASI) score, the proportion of patients achieving a 50%, 75% and 90% reduction in DASI (DASI50, DASI75, DASI90) and the serum level of TNF-α were used to assess the efficacy at different times. Adverse reactions were also recorded and evaluated. The results were statistically analyzed by nonparametric Friedman test and repetitive measurement ANOVA using the software SPSS19.0. Results: After 4 weeks treatment, the DASI score decreased form 56.33±7.02 to 0.50±0.91 (P<0.01) . The DASI50, DASI75 and DASI90 were all increased to 12 (100%) . The serum level of TNF-α decreased form (43.74±41.62) pg/ml to (3.03±0.47) pg/ml (P<0.01) . Statistically significant difference was observed from the above indexes. There were no adverse reactions in clinical application. Conclusion: Recombinant human tumor necrosis factor receptor Ⅱ-IgG Fc fusion protein may be a safe and effective drug in the treatment of OMLDT.