title: HR-MALDI-MS imaging assisted screening of β-carboline alkaloids discovered from Mycena metata.
abstract: Fruiting bodies of Mycena metata were screened for the presence of new secondary metabolites by means of HPLC-UV, LC-HR-ESIMS, and high-resolution matrix-assisted laser desorption/ionization mass spectrometry imaging (HR-MALDI-MS imaging). Thus, a new β-carboline alkaloid, 6-hydroxymetatacarboline D (1d), was isolated from fruiting bodies of M. metata. 6-Hydroxymetatacarboline D consists of a highly substituted β-carboline skeleton, which is likely to be derived biosynthetically from l-tryptophan, 2-oxoglutaric acid, l-threonine, and l-proline. The structure of the alkaloid was established by 2D NMR spectroscopic methods and HR-ESIMS. Moreover, by extensive application of LC-HR-ESIMS, LC-HR-ESIMS/MS, and LC-HR-ESIMS(3) techniques we were able to elucidate the structures of a number of accompanying β-carboline alkaloids, 1a-1c, 1e-1i, and 2a-2g, structurally closely related to 6-hydroxymetatacarboline D, which are present in M. metata in minor amounts. The absolute configuration of the stereogenic centers of the β-carboline alkaloids was determined by GC-MS comparison with authentic synthetic samples after hydrolytic cleavage and derivatization of the resulting amino acids.
authors: Institut für Organische und Analytische Chemie, Universität Bremen, Leobener Straße NW2C, Bremen, Germany.
authors: Robert J R
authors: RJ
authors: Jaeger
authors: Marc
authors: M
authors: Lamshöft
authors: Sebastian
authors: S
authors: Gottfried
authors: Michael
authors: M
authors: Spiteller
authors: Peter
authors: P
authors: Spiteller
mesh_terms: D000363:Agaricales / Q000737:chemistry*; D000470:Alkaloids / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D001407:Bacillus / Q000187:drug effects; D002243:Carbolines / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D002963:Cladosporium / Q000187:drug effects; D004926:Escherichia coli / Q000187:drug effects; D048690:Fruiting Bodies, Fungal / Q000737:chemistry; D005858:Germany; D008826:Microbial Sensitivity Tests; D015394:Molecular Structure; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*
chemical_list: C579784:6-hydroxymetatacarboline D; D000470:Alkaloids; D002243:Carbolines