Jing Shao1, MengXiang Zhang1, TianMing Wang2, Yue Li3, ChangZhong Wang1. 1. a Laboratory of Microbiology and Immunology, School of Chinese and Western Integrative Medicine , Anhui University of Chinese Medicine , Hefei , China . 2. b Laboratory of Biochemistry and Molecular Biology, School of Chinese and Western Integrative Medicine , Anhui University of Chinese Medicine , Hefei , China , and. 3. c Gynecology of Traditional Chinese Medicine, Clinical College of Traditional Chinese Medicine , Anhui University of Chinese Medicine , Hefei , China.
Abstract
CONTEXT: Fungal infections caused by fluconazole-resistant Candida albicans are an intractable clinical problem, calling for new efficient antifungal drugs. Kaempferol, an active flavonoid, has been considered a potential candidate against Candida species. OBJECTIVE: This work investigates the resistance reversion of kaempferol in fluconazole-resistant C. albicans and the underlying mechanism. MATERIALS AND METHODS: The antifungal activities of fluconazole and/or kaempferol were assessed by a series of standard procedures including broth microdilution method, checkerboard assay and time-kill (T-K) test in nine clinical strains as well as a standard reference isolate of C. albicans. Subsequently, the morphological changes, the efflux of rhodamine 6G, and the expressions of CDR 1, CDR 2, and MDR 1 were analysed by scanning electron microscope (SEM), inverted fluorescence microscope and quantitative reverse transcription polymerase chain reaction (qRT-PCR) in C. albicans z2003. RESULTS: For all the tested C. albicans strains, the minimum inhibitory concentrations (MICs) of fluconazole and kaempferol ranged 0.25-32 and 128-256 μg/mL with a range of fractional inhibitory concentration index of 0.257-0.531. In C. albicans z2003, the expression of both CDR 1 and CDR 2 were decreased after exposure to kaempferol alone with negligible rhodamine 6G accumulation, while the expression of CDR 1, CDR 2 and MDR 1 were all decreased when fluconazole and kaempferol were used concomitantly with notable fluorescence of rhodamine 6G observed. DISCUSSION AND CONCLUSION: Kaempferol-induced reversion in fluconazole-resistant C. albicans might be likely due to the suppression of the expression of CDR1, CDR2 and MDR1.
CONTEXT: Fungal infections caused by fluconazole-resistant Candida albicans are an intractable clinical problem, calling for new efficient antifungal drugs. Kaempferol, an active flavonoid, has been considered a potential candidate against Candida species. OBJECTIVE: This work investigates the resistance reversion of kaempferol in fluconazole-resistant C. albicans and the underlying mechanism. MATERIALS AND METHODS: The antifungal activities of fluconazole and/or kaempferol were assessed by a series of standard procedures including broth microdilution method, checkerboard assay and time-kill (T-K) test in nine clinical strains as well as a standard reference isolate of C. albicans. Subsequently, the morphological changes, the efflux of rhodamine 6G, and the expressions of CDR 1, CDR 2, and MDR 1 were analysed by scanning electron microscope (SEM), inverted fluorescence microscope and quantitative reverse transcription polymerase chain reaction (qRT-PCR) in C. albicans z2003. RESULTS: For all the tested C. albicans strains, the minimum inhibitory concentrations (MICs) of fluconazole and kaempferol ranged 0.25-32 and 128-256 μg/mL with a range of fractional inhibitory concentration index of 0.257-0.531. In C. albicans z2003, the expression of both CDR 1 and CDR 2 were decreased after exposure to kaempferol alone with negligible rhodamine 6G accumulation, while the expression of CDR 1, CDR 2 and MDR 1 were all decreased when fluconazole and kaempferol were used concomitantly with notable fluorescence of rhodamine 6G observed. DISCUSSION AND CONCLUSION:Kaempferol-induced reversion in fluconazole-resistant C. albicans might be likely due to the suppression of the expression of CDR1, CDR2 and MDR1.
Authors: Mohammad A I Al-Hatamleh; Jennifer C Boer; Kirsty L Wilson; Magdalena Plebanski; Rohimah Mohamud; Mohd Zulkifli Mustafa Journal: Biomolecules Date: 2020-06-18