Omphalotin, A New Cyclic Peptide with Potent Nematicidal Activity from<i>Omphalotus Olearius</i>II. Isolation and Structure Determination

Abstract

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