title: Stress-driven discovery of metabolites from the phytopathogenic fungus Leptosphaeria maculans: structure and activity of leptomaculins A-E.
abstract: A search for stress inducing metabolites produced by the plant pathogenic fungus Leptosphaeria maculans led to the isolation and structure elucidation of eight new metabolites, the leptomaculins and deacetylleptomaculins A-E. The chemical structures and absolute stereochemistry of the new metabolites were deduced by detailed analysis of 1D and 2D NMR spectroscopic data and chemical degradation of the toxin sirodesmin PL. Leptomaculins A and B are the first examples of naturally occurring 2,3-oxopiperazinethione and 2,3-dioxopiperazine, respectively. Stress inducing activity was found in the fungal phytotoxins sirodesmin PL and deacetylsirodesmin PL but not in any of the new leptomaculins, phomalide or phomamide. A metabolic pathway for biosynthesis of the first 2,3-(di)oxopiperazine(thione) from sirodesmin PL is proposed.
authors.affiliation: Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, SK, Canada S7N 5C9. s.pedras@usask.ca
authors.forename: M Soledade C
authors.initials: MS
authors.lastname: Pedras
authors.forename: Yang
authors.initials: Y
authors.lastname: Yu
mesh_terms: D001203:Ascomycota / Q000737:chemistry* / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy / Q000379:methods / Q000592:standards; D008968:Molecular Conformation; D010802:Phylogeny; D010879:Piperazines / Q000737:chemistry* / Q000302:isolation & purification; D012015:Reference Standards; D013237:Stereoisomerism
chemical_list: D010879:Piperazines