Antifungal Cyclopeptolide from Fungal Saprophytic Antagonist Ulocladium atrum

The saprophytic fungus Ulocladium atrum Preuss is a promising biological control agent for Botrytis cinerea in greenhouse- and field-grown crops. However, despite its known potent antifungal activity, no antifungal substance has yet been reported. In an effort to characterize the antifungal substance from U. atrum, we isolated an antibiotic peptide. Based on extensive spectroscopic analyses, its structure was established as a cyclopeptolide with a high portion of N-methylated amino acids, and its ¹H and ∨13C chemical shifts were completely assigned based on extensive 1D and 2D NMR experiments.