RESUMEN
A series of caffeic acid amides were designed, synthesized, and their synergistic activity with fluconazole against fluconazole-resistant Candida albicans was evaluated in vitro. The title caffeic acid amides 3-30 except 26 exhibited potent activity, and the subsequent SAR study was conducted. Compound 3, 5, 21, and 34c, at a concentration of 1.0 µg/ml, decreased the MIC80 of fluconazole from 128.0 µg/ml to 1.0-0.5 µg/ml against the fluconazole-resistant C. albicans. This result suggests that the caffeic acid amides, as synergists, can sensitize drug-resistant fungi to fluconazole. The SAR study indicated that the dihydroxyl groups and the amido groups linking to phenyl or heterocyclic rings are the important pharmacophores of the caffeic acid amides.
Asunto(s)
Amidas/química , Ácidos Cafeicos/química , Candida albicans/efectos de los fármacos , Diseño de Fármacos , Fluconazol/química , Amidas/administración & dosificación , Ácidos Cafeicos/administración & dosificación , Candida albicans/fisiología , Evaluación Preclínica de Medicamentos/métodos , Farmacorresistencia Fúngica/efectos de los fármacos , Farmacorresistencia Fúngica/fisiología , Sinergismo Farmacológico , Fluconazol/administración & dosificación , Pruebas de Sensibilidad Microbiana/métodosRESUMEN
Over-expression of the Candida drug resistance gene CDR1 is a common mechanism generating azole-resistant Candida albicans in clinical isolates. CDR1 is transcriptionally activated through the binding of the transcription factor Tac1p to the cis-acting drug-responsive element (DRE) in its promoter. We previously demonstrated that the combination of fluconazole (FLC) and berberine (BBR) produced significant synergy when used against FLC-resistant C. albicans in vitro. In this study, we found that BBR inhibited both the up-regulation of CDR1 mRNA and the transport function of Cdr1p induced by fluphenazine (FNZ). Further, electrophoretic mobility shift assays suggested that the transcription activation complex of protein-DRE was disrupted by BBR, and electrospray ionization mass spectrometry analysis showed that BBR bound to the DRE of CDR1. Thus we propose that BBR inhibits the FNZ-induced transcriptional activation of CDR1 in C. albicans by blocking transcription factor binding to the DRE of CDR1. These results contribute to our understanding of the mechanism of synergistic effect of BBR and FLC.