title: Dereplication of depsides from the lichen Pseudevernia furfuracea by centrifugal partition chromatography combined to 13C nuclear magnetic resonance pattern recognition.
abstract: Lichens produce a diversity of secondary metabolites, among them depsides comprised of two or more hydroxybenzoic acid units linked by ester, ether, or CC-bonds. During classic solid support-based purification processes, depsides are often hydrolyzed and in many cases time, consuming procedures result only in the isolation of decomposition products. In an attempt to avoid extensive purification steps while maintaining metabolite structure integrity, we propose an alternative method to identify the major depsides of a lichen crude extract (Pseudevernia furfuracea var. ceratea (Ach.) D. Hawksw., Parmeliaceae) directly within mixtures. Exploiting the acidic character of depsides and differences in polarity, the extract was fractionated by centrifugal partition chromatography in the pH-zone refining mode resulting in twelve simplified mixtures of depsides. After (13)C nuclear magnetic resonance analysis of the produced fractions, the major molecular structures were directly identified within the fraction series by using a recently developed pattern recognition method, which combines spectral data alignment and hierarchical clustering analysis. The obtained clusters of (13)C chemical shifts were assigned to their corresponding molecular structures with the help of an in-house (13)C NMR chemical shift database, resulting in six unambiguously identified compounds, namely methyl β-orcinolcarboxylate (1), atranorin (2), 5-chloroatranorin (3), olivetol carboxylic acid (4), olivetoric acid (5), and olivetonide (6).
authors.affiliation: Institute of Pharmacy/Pharmacognosy, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria.
authors.forename: Sarah K
authors.initials: SK
authors.lastname: Oettl
authors.affiliation: Institut de Chimie Moléculaire de Reims (UMR CNRS 7312), SFR CAP'sANTE, UFR de Pharmacie, Université de Reims Champagne-Ardenne, BP 1039, 51687 Reims Cedex 2, France. Electronic address: jane.hubert@univ-reims.fr.
authors.forename: Jane
authors.initials: J
authors.lastname: Hubert
authors.affiliation: Institut de Chimie Moléculaire de Reims (UMR CNRS 7312), SFR CAP'sANTE, UFR de Pharmacie, Université de Reims Champagne-Ardenne, BP 1039, 51687 Reims Cedex 2, France.
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Nuzillard
authors.affiliation: Institute of Pharmacy/Pharmacognosy, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria.
authors.forename: Hermann
authors.initials: H
authors.lastname: Stuppner
authors.affiliation: Institut de Chimie Moléculaire de Reims (UMR CNRS 7312), SFR CAP'sANTE, UFR de Pharmacie, Université de Reims Champagne-Ardenne, BP 1039, 51687 Reims Cedex 2, France.
authors.forename: Jean-Hugues
authors.initials: JH
authors.lastname: Renault
authors.affiliation: Institute of Pharmacy/Pharmacognosy, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria.
authors.forename: Judith M
authors.initials: JM
authors.lastname: Rollinger
mesh_terms: D005591:Chemical Fractionation; D002845:Chromatography; D002853:Chromatography, Liquid; D016000:Cluster Analysis; D053630:Depsides / Q000032:analysis / Q000302:isolation & purification*; D008011:Lichens / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy
chemical_list: D053630:Depsides
keywords: (13)C nuclear magnetic resonance; Centrifugal partition chromatography; Depside; Dereplication; Hierarchical clustering analysis; Lichen