title: Purpurolic acid: A new natural alkaloid from Claviceps purpurea (Fr.) Tul.
abstract: A novel secondary metabolite from the sclerotia of Claviceps purpurea (Fr.) Tul. is described; the structure is based on (1)H and (13)C NMR spectroscopy and electrospray mass spectrometry. It has an elemental composition C10H16N2O7 and is comprised mainly of proline and alanine moieties, although without peptide linkage. Notably, these amino-acids are also components of the cyclic tripeptide side chain of several classic ergoline alkaloids. Designated as purpurolic acid, the new compound is the principal free amino-acid in ergot and its natural abundance exceeds that of the ergoline alkaloids with which it accumulates in parallel during parasitic development. In contrast, it does not accumulate in the fungus in axenic culture, even when ergotamine is synthesised. The extent to which the compound is a metabolite of other ergot fungi worldwide is unknown. Biological activity and metabolic significance also remain unknown, but purpurolic acid could become a biomarker for detection of ergot contamination in agricultural products of temperate latitudes.
authors.affiliation: Drug Metabolism and Pharmacokinetics, GlaxoSmithKline, Ware, Herts, SG12 0DP, UK.
authors.forename: Andrew
authors.initials: A
authors.lastname: Roberts
authors.affiliation: Drug Metabolism and Pharmacokinetics, GlaxoSmithKline, Ware, Herts, SG12 0DP, UK.
authors.forename: Claire
authors.initials: C
authors.lastname: Beaumont
authors.affiliation: Biochemistry Department, Imperial College, London, SW7 2AZ, UK.
authors.forename: Azita
authors.initials: A
authors.lastname: Manzarpour
authors.affiliation: Centre for Environmental Policy, Imperial College London, London, SW7 2AZ, UK.
authors.forename: Peter
authors.initials: P
authors.lastname: Mantle
mesh_terms: D000470:Alkaloids / Q000737:chemistry* / Q000378:metabolism; D002967:Claviceps / Q000737:chemistry / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D015394:Molecular Structure
chemical_list: D000470:Alkaloids
keywords: Biomarker; Ergot; Ion-exchange chromatography; Parasitism; Preparative electrophoresis; Sclerotia