6′-Hydroxy-3′-methoxy-mitorubrin, a New Potentiator of Antifungal Miconazole Activity, Produced by Penicillium radicum FKI-3765-2

Abstract

A new mitorubrin congener designated 6′-hydroxy-3′-methoxy-mitorubrin (1) was isolated along with structurally related 4′-hydroxy-3′-methoxy-(S)-mitorubrin (2) and monomethyl-(S)-mitorubrin (3) from the culture broth of Penicillium radicum FKI-3765-2 by solvent extraction, octadecyl silyl (ODS) column chromatography and HPLC. The structure of 1 was elucidated by various spectral analyses, including NMR experiments. They have a common isochromane-like ring with a similar hydrophobic side chain. These compounds moderately potentiated miconazole activity against Candida albicans.