title: Qualitative and spatial metabolite profiling of lichens by a LC-MS approach combined with optimised extraction.
abstract: BACKGROUND
  Lichens are self-sustaining partnerships comprising fungi as shape-forming partners for their enclosed symbiotic algae. They produce a tremendous diversity of metabolites (1050 metabolites described so far).
  
  
  OBJECTIVE
  A comparison of metabolic profiles in nine lichen species belonging to three genera (Lichina, Collema and Roccella) by using an optimised extraction protocol, determination of the fragmentation pathway and the in situ localisation for major compounds in Roccella species.
  
  
  METHODS
  Chemical analysis was performed using a complementary study combining a Taguchi experimental design with qualitative analysis by high-performance liquid chromatography coupled with mass spectrometry techniques.
  
  
  RESULTS
  Optimal conditions to obtain the best total extraction yield were determined as follows: mortar grinding to a fine powder, two successive extractions, solid:liquid ratio (2:60) and 700 rpm stirring. Qualitative analysis of the metabolite profiling of these nine species extracted with the optimised method was corroborated using MS and MS/MS approaches. Nine main compounds were identified: 1 β-orcinol, 2 orsellinic acid, 3 putative choline sulphate, 4 roccellic acid, 5 montagnetol, 6 lecanoric acid, 7 erythrin, 8 lepraric acid and 9 acetylportentol, and several other compounds were reported. Identification was performed using the m/z ratio, fragmentation pathway and/or after isolation by NMR analysis. The variation of the metabolite profile in differently organised parts of two Roccella species suggests a specific role of major compounds in developmental stages of this symbiotic association.
  
  
  CONCLUSIONS
  Metabolic profiles represent specific chemical species and depend on the extraction conditions, the kind of the photobiont partner and the in situ localisation of major compounds.
authors.affiliation: UMR CNRS 6226, Institut des Sciences Chimiques de Rennes, Equipe PNSCM 'Produits naturels - Synthèses - Chimie Médicinale', UFR Sciences Pharmaceutiques et Biologiques, Université de Rennes 1, Université Européenne de Bretagne, 2 Avenue du Pr. Léon Bernard, F-35043, Rennes, France.
authors.forename: Delphine
authors.initials: D
authors.lastname: Parrot
authors.forename: Tiphaine
authors.initials: T
authors.lastname: Peresse
authors.forename: Eric
authors.initials: E
authors.lastname: Hitti
authors.forename: Daniel
authors.initials: D
authors.lastname: Carrie
authors.forename: Martin
authors.initials: M
authors.lastname: Grube
authors.forename: Sophie
authors.initials: S
authors.lastname: Tomasi
mesh_terms: D002851:Chromatography, High Pressure Liquid; D008011:Lichens / Q000737:chemistry / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D055442:Metabolome; D055432:Metabolomics / Q000379:methods*; D015394:Molecular Structure; D010936:Plant Extracts / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D053719:Tandem Mass Spectrometry
chemical_list: D010936:Plant Extracts
keywords: Localisation; Taguchi experimental design; metabolite profile; symbiotic organisms