title: Hymenosetin, a 3-decalinoyltetramic acid antibiotic from cultures of the ash dieback pathogen, Hymenoscyphus pseudoalbidus.
abstract: A 3-decalinoyltetramic acid, for which the trivial name hymenosetin is proposed, was isolated from crude extracts of a virulent strain of the ash dieback pathogen, Hymenoscyphus pseudoalbidus (="Chalara fraxinea"). This compound was produced only under certain culture conditions in submerged cultures of the fungus. Its planar structure was determined by NMR spectroscopy and by mass spectrometry. The absolute stereochemistry was assigned by CD spectroscopy and HETLOC data. Hymenosetin exhibited broad spectrum antibacterial and antifungal activities (including strong inhibition of MRSA), as well as moderate cytotoxic effects. So far, the metabolite proved inactive in assays for evaluation of phytotoxicity, whereas viridiol, another secondary metabolite known from H. pseudoalbidus, was regarded as phytotoxic principle of the pathogen against its host, Fraxinus excelsior. Further studies will show whether hymenosetin constitutes a defence metabolite that is produced by the pathogenic fungus to combat other microbes and fungi in the natural environment.
authors: Helmholtz Centre for Infection Research GmbH (HZI), Department Microbial Drugs, Inhoffenstraße 7, 38124 Braunschweig, Germany.
authors: Sandra
authors: S
authors: Halecker
authors: Helmholtz Centre for Infection Research GmbH (HZI), Department Microbial Drugs, Inhoffenstraße 7, 38124 Braunschweig, Germany.
authors: Frank
authors: F
authors: Surup
authors: Helmholtz Centre for Infection Research GmbH (HZI), Department Microbial Drugs, Inhoffenstraße 7, 38124 Braunschweig, Germany.
authors: Eric
authors: E
authors: Kuhnert
authors: Helmholtz Centre for Infection Research GmbH (HZI), Department Microbial Drugs, Inhoffenstraße 7, 38124 Braunschweig, Germany; German Centre for Infection Research (DZIF), Partner Site Hannover-Braunschweig, Inhoffenstraße 7, 38124 Braunschweig, Germany.
authors: Kathrin I
authors: KI
authors: Mohr
authors: Institute of Organic Chemistry, Technical University of Braunschweig, Hagenring 30, 38106 Braunschweig, Germany.
authors: Nelson L
authors: NL
authors: Brock
authors: Institute of Organic Chemistry, Technical University of Braunschweig, Hagenring 30, 38106 Braunschweig, Germany.
authors: Jeroen S
authors: JS
authors: Dickschat
authors: Institute of Microbiology, Technical University of Braunschweig, Spielmannstraße 7, 38106 Braunschweig, Germany.
authors: Corina
authors: C
authors: Junker
authors: Institute of Microbiology, Technical University of Braunschweig, Spielmannstraße 7, 38106 Braunschweig, Germany.
authors: Barbara
authors: B
authors: Schulz
authors: Helmholtz Centre for Infection Research GmbH (HZI), Department Microbial Drugs, Inhoffenstraße 7, 38124 Braunschweig, Germany; German Centre for Infection Research (DZIF), Partner Site Hannover-Braunschweig, Inhoffenstraße 7, 38124 Braunschweig, Germany. Electronic address: marc.stadler@helmholtz-hzi.de.
authors: Marc
authors: M
authors: Stadler
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D001203:Ascomycota / Q000737:chemistry* / Q000254:growth & development; D046508:Culture Techniques; D008826:Microbial Sensitivity Tests; D011760:Pyrrolidinones / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D011760:Pyrrolidinones; C000592499:hymenosetin; C009435:tetramic acid
keywords: Ash dieback; Hymenoscyphus pseudoalbidus; MRSA; Natural products; Secondary metabolite; Structure elucidation; Tetramic acid