title: Hypoxyvermelhotins A-C, new pigments from Hypoxylon lechatii sp. nov.
abstract: A new species of Hypoxylon was discovered, based on material collected in French Guiana and recognised on the basis of new combination of morpholological characters in comparison with type and authentic material of macroscopically similar taxa. These findings were corroborated by the rather isolated positions of its ITS-nrDNA and beta-tubulin DNA sequences in molecular phylogenies. However, the most salient feature of this fungus only became evident by a comparison of its stromatal HPLC profile, revealing several secondary metabolites that were hitherto not observed in stromata of any other member of the Xylariaceae. Part of the stromata were subsequently extracted to isolate these apparently specific components, using preparative chromatography. Five metabolites were obtained in pure state, and their chemical structures were elucidated by means of high resolution mass spectrometry and nuclear magnetic resonance spectroscopy. They turned out to be tetramic acid derivatives of the so-called vermelhotin type. Aside from vermelhotin, previously isolated from cultures of endophytic fungi, we identified three novel congeners, for which the trivial names hypoxyvermelhotins A-C were proposed. Like vermelhotin, they constitute orange-red pigments and a preliminary biological characterisation revealed them to have rather strong cytotoxic and moderate to weak antimicrobial effects. These results further illustrate the high diversity of unique secondary metabolites in stromata of the hypoxyloid Xylariaceae, a family in which biological diversity seems to parallel the chemical diversity of their bioactive principles to a great extent.
authors: Helmholtz-Zentrum für Infektionsforschung GmbH, Department of Microbial Drugs, Inhoffenstraße 7, 38124 Braunschweig, Germany.
authors: Eric
authors: E
authors: Kuhnert
authors: Helmholtz-Zentrum für Infektionsforschung GmbH, Department of Microbial Drugs, Inhoffenstraße 7, 38124 Braunschweig, Germany.
authors: Simone
authors: S
authors: Heitkämper
authors: Las Muros, F-09420 Rimont, France.
authors: Jacques
authors: J
authors: Fournier
authors: Helmholtz-Zentrum für Infektionsforschung GmbH, Department of Microbial Drugs, Inhoffenstraße 7, 38124 Braunschweig, Germany.
authors: Frank
authors: F
authors: Surup
authors: Helmholtz-Zentrum für Infektionsforschung GmbH, Department of Microbial Drugs, Inhoffenstraße 7, 38124 Braunschweig, Germany. Electronic address: marc.stadler@helmholtz-hzi.de.
authors: Marc
authors: M
authors: Stadler
mesh_terms: D002851:Chromatography, High Pressure Liquid; D016000:Cluster Analysis; D004271:DNA, Fungal / Q000737:chemistry / Q000235:genetics; D021903:DNA, Ribosomal Spacer / Q000737:chemistry / Q000235:genetics; D005616:French Guiana; D008969:Molecular Sequence Data; D015394:Molecular Structure; D010802:Phylogeny; D010860:Pigments, Biological / Q000032:analysis* / Q000737:chemistry*; D011760:Pyrrolidinones / Q000032:analysis / Q000737:chemistry; D017422:Sequence Analysis, DNA; D014404:Tubulin / Q000235:genetics; D013098:Xylariales / Q000737:chemistry* / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification
chemical_list: D004271:DNA, Fungal; D021903:DNA, Ribosomal Spacer; D010860:Pigments, Biological; D011760:Pyrrolidinones; D014404:Tubulin; C009435:tetramic acid
keywords: Ascomycota; Chemotaxonomy; Phylogeny; Taxonomy; Xylariales