Sch 54445: a new polycyclic xanthone with highly potent antifungal activity produced by Actinoplanes sp

A novel antifungal agent, Sch 54445, was isolated from the fermentation broth of an Actinoplanes species. Sch 54445 was identified as a polycyclic xanthone related to the albofungin family of compounds on the basis of analyses of spectroscopic data. As a broad-spectrum antifungal agent, Sch 54445 exhibits highly potent activities against various yeasts and dermatophytes with MIC values approximately 0.00038 microgram/mL.