title: Characterization and identification of mycosporines-like compounds in cyanolichens. Isolation of mycosporine hydroxyglutamicol from Nephroma laevigatum Ach.
abstract: Mycosporine-like compounds, comprising mycosporines and mycosporine-like amino acids (MAAs) are UV protecting secondary metabolites described in organisms such as fungi, algae, cyanobacteria or animals. Lichens however, were only poorly investigated for such constituents so far. Here, a method for the characterization of mycosporines and MAAs in purified aqueous extracts, involving HPTLC coupled to spectrophotodensitometry, HPLC-DAD-MS(n) and UPLC-HRMS analysis, is described. This optimized protocol was validated on three algae and one cyanolichen containing known MAAs and mycosporines, and then applied to 18 cyanolichen species. Analyses revealed the presence of five already described mycosporine-like compounds in the investigated species, including mycosporine serinol in Lichina and Peltigera species and mycosporine glutamicol in Degelia plumbea. Apart from that, eight unknown mycosporine-like compounds were detected and tentatively characterized on the basis of their DAD spectra and their MS(n) and HRMS data: two in the alga Porphyra dioica and six in cyanolichen species belonging to the genera Degelia, Nephroma and Stereocaulon. From Nephroma laevigatum, the mycosporine hydroxyglutamicol was preparatively isolated and identified through HRMS, 1D and 2D NMR spectroscopic data. The optimized analytical protocol allowed the characterization of mycosporine-like compounds in small amounts of material and confirmed the potential of cyanolichens as a source of mycosporine compounds. It should also be applicable to investigate lichen species with green algae photobionts for mycosporine-like compounds.
authors.affiliation: Equipe PNSCM "Produits Naturels, Synthèses et Chimie Médicinale", UMR CNRS 6226, Faculté des Sciences Pharmaceutiques et Biologiques, Université de Rennes 1, 2 Av. du Pr. Léon Bernard, 35043 Rennes Cedex, France.
authors.forename: Catherine
authors.initials: C
authors.lastname: Roullier
authors.forename: Marylène
authors.initials: M
authors.lastname: Chollet-Krugler
authors.forename: Eva-Maria
authors.initials: EM
authors.lastname: Pferschy-Wenzig
authors.forename: Anne
authors.initials: A
authors.lastname: Maillard
authors.forename: Gerald N
authors.initials: GN
authors.lastname: Rechberger
authors.forename: Béatrice
authors.initials: B
authors.lastname: Legouin-Gargadennec
authors.forename: Rudolf
authors.initials: R
authors.lastname: Bauer
authors.forename: Joël
authors.initials: J
authors.lastname: Boustie
mesh_terms: D000596:Amino Acids / Q000737:chemistry / Q000302:isolation & purification; D001203:Ascomycota / Q000737:chemistry; D005591:Chemical Fractionation / Q000379:methods; D000460:Chlorophyta / Q000737:chemistry; D002850:Chromatography, Gel / Q000379:methods*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D003511:Cyclohexanols / Q000737:chemistry / Q000302:isolation & purification*; D003512:Cyclohexanones / Q000737:chemistry / Q000302:isolation & purification*; D005960:Glucosides / Q000737:chemistry / Q000302:isolation & purification*; D008011:Lichens / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D010936:Plant Extracts / Q000737:chemistry; D011409:Propylene Glycols / Q000737:chemistry / Q000302:isolation & purification*
chemical_list: D000596:Amino Acids; D003511:Cyclohexanols; D003512:Cyclohexanones; D005960:Glucosides; D010936:Plant Extracts; D011409:Propylene Glycols; C561985:mycosporine hydroxyglutamicol; C474430:mycosporine-glutamicol-glucoside; C544070:mycosporine-serinol