Fluconazole assists berberine to kill fluconazole-resistant Candida albicans.
It was found in our previous study that berberine (BBR) and fluconazole (FLC) used concomitantly exhibited a synergism against FLC-resistant Candida albicans in vitro. The aim of the present study was to clarify how BBR and FLC worked synergistically and the underlying mechanism. Antifungal time-kill curves indicated that the synergistic effect of the two drugs was BBR dose dependent rather than FLC dose dependent. In addition, we found that BBR accumulated in C. albicans cells, especially in the nucleus, and resulted in cell cycle arrest and significant change in the transcription of cell cycle-related genes. Besides BBR, other DNA intercalators, including methylene blue, sanguinarine, and acridine orange, were all found to synergize with FLC against FLC-resistant C. albicans. Detection of intracellular BBR accumulation by fluorescence measurement showed that FLC played a role in increasing intracellular BBR concentration, probably due to its effect in disrupting the fungal cell membrane. Similar to the case with FLC, other antifungal agents acting on the cell membrane were able to synergize with BBR. Interestingly, we found that the efflux of intracellular BBR was FLC independent but strongly glucose dependent and associated with the drug efflux pump Cdr2p. These results suggest that BBR plays a major antifungal role in the synergism of FLC and BBR, while FLC plays a role in increasing the intracellular BBR concentration.
New Drug Research and Development Center, School of Pharmacy, Second Military Medical University, Shanghai, China.
De-Dong
DD
Li
Yi
Y
Xu
Da-Zhi
DZ
Zhang
Hua
H
Quan
Eleftherios
E
Mylonakis
Dan-Dan
DD
Hu
Ming-Bang
MB
Li
Lan-Xue
LX
Zhao
Liang-Hua
LH
Zhu
Yan
Y
Wang
Yuan-Ying
YY
Jiang
D000165:Acridine Orange / Q000494:pharmacology; D000935:Antifungal Agents / Q000494:pharmacology*; D053119:Benzophenanthridines / Q000494:pharmacology; D001599:Berberine / Q000494:pharmacology*; D001692:Biological Transport; D002176:Candida albicans / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D059447:Cell Cycle Checkpoints / Q000187:drug effects; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D025141:Drug Resistance, Fungal / Q000235:genetics; D004357:Drug Synergism; D015725:Fluconazole / Q000494:pharmacology*; D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal; D007364:Intercalating Agents / Q000494:pharmacology; D007546:Isoquinolines / Q000494:pharmacology; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism; D008751:Methylene Blue / Q000494:pharmacology; D008826:Microbial Sensitivity Tests
D000935:Antifungal Agents; D053119:Benzophenanthridines; D018797:Cell Cycle Proteins; D005656:Fungal Proteins; D007364:Intercalating Agents; D007546:Isoquinolines; D026901:Membrane Transport Proteins; D001599:Berberine; D015725:Fluconazole; C005705:sanguinarine; D000165:Acridine Orange; D008751:Methylene Blue