Omphalotin, A New Cyclic Peptide with Potent Nematicidal Activity fromOmphalotus OleariusII. Isolation and Structure Determination

Abstract The structure of the potent nematicide omphalotin, isolated from the mycelia of the basidiomycete Omphalotus olearius, was determined by spectroscopic techniques. Omphalotin is a cyclic dodecapeptide consisting of 3 glycine, 5 valine, 3 isoleucine and 1 tryptophane, and 9 of the 12 β-nitrogens are methylated. HMBC and NOESY correlations between the N-methyl groups and the β-carbons/β-hydrogens established the sequence of amino acids. Key Words: Omphalotus oleariusomphalotincyclopeptidestructure determination