New beauvericins, potentiators of antifungal miconazole activity, produced by Beauveria sp FKI-1366 -: I.: Taxonomy, fermentation, isolation and biological properties

Three new beauvericins, designated beauvericins D, E and F, were isolated along with known beauvericin and beauvericin A, from the culture of Beauveria sp. FKI-1366 by solvent extraction, ODS column chromatography and HPLC. These compounds potentiate miconazole activity against not only wild Candida albicans but also fluconazole resistant C. albicans. Beauvericins D and E decreased the IC50 value of miconazole against fluconazole resistant C. albicans from 1.3 mum to 0.25 and 0.31 mum, respectively.