Chelerythrine, a major ingredient isolated from Macleaya cordata (Willd.) R. Br. (Papaveraceae), inhibits fluconazole-resistant Candida albicans biofilms

Abstract

IntroductionIt has a long history to employ Macleaya cordata (Willd.) R. Br. (Papaveraceae) for the treatment of a variety of diseases in China. Chelerythrine, one of the major of M. cordata with detoxifying and anti-inflammatory effect, is reported to combat bacteria and fungus. This work aims to explore the effect of chelerythrine against fluconazole-resistant Candida albicans and also illustrate its potential mechanism. MethodsThe microdilution method, following CLSI-M27-A3 was used to evaluate the effect of chelerythrine against fluconazole-resistant C. albicans. Meanwhile, biofilm viability was assessed by 2,3-Bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT) assay and cell morphology was observed by inverted microscope. Real Time Quantitative PCR (RT-qPCR) and confocal laser scanning microscope were employed to detect the mRNA expression and 2′,7′-Dichlorodihydrofluorescein diacetate (DCFH-DA) staining, respectively. Fluorescence intensity was quantified by flow cytometry. ResultsThe total alkaloids extract of M. cordata significantly inhibited the viability of C. albicans, concentration of which in 64 μg/ml presented to 40% inhibitory effect. In addition, the minimum inhibitory concentration (MIC)80 for chelerythrine was 8 μM, whereas chelerythrine in 4 μM inhibited biofilm formation by 47.7%. Further studies revealed that chelerythrine reduced the hydrophobicity of cellular surface, inhibited hyphal growth, downregulated the expression of genes related to cyclic adenosine monophosphate (cAMP) pathway, increased cellular permeability and promoted the production of reactive oxygen species (ROS). ConclusionChelerythrine inhibited biofilm formation by decreasing cellular surface hydrophobicity (CSH) and inhibiting the cAMP pathway. Chelerythrine increased cellular permeability and promoted the production of reactive oxygen species, which leads to the cell death of fluconazole-resistant C. albicans.