Isolation and identification of antifungal polyesters from the marine fungus Hypoxylon oceanicum LL-15G256

Cultures of the marine fungus Hypoxylon oceanicum (LL-15G256) were found to have potent antifungal activity in assays designed to detect inhibitors of fungal cell wall biosynthesis. Bio-activity guided isolation provided the macrocyclic polyesters 15G256α (), 15G256α-1 () and 15G256β () that were partially responsible for the antifungal activity. In addition, fermentation beers contained a series of related, but unreported metabolites designated 15G256ι (), 15G256ω (), 15G256ο (), 15G256α-2 (), 15G256β-2 (), 15G256ν () and 15G256π (). Their isolation, characterization and structures are described here and a biosynthetic sequence is proposed.