title: Stictic acid derivatives from the lichen Usnea articulata and their antioxidant activities.
abstract: Two new beta-orcinol depsidones, 1 and 2, together with 13 known compounds were isolated from the lichen Usnea articulata. The structures of 1 and 2 were elucidated by spectroscopic analyses and those of known compounds by comparison of their spectroscopic data with literature values or by direct comparison with authentic standards. Compounds 1, 2, and 5 exhibited moderate antiradical activity in the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. The depsidones 4 and 5 showed better superoxide anion scavenging activity (IC50 = 566 and 580 microM, respectively) than quercetin (IC50 = 754 microM).
authors.affiliation: Institut de Chimie de Rennes, EA 4090 Substances Lichéniques et Photoprotection, Faculté de Pharmacie, Université de Rennes, 2 Avenue du Professeur Léon Bernard, 35043 Rennes Cedex, France. francoise.le-devehat@univ-rennes1.fr
authors.forename: Françoise
authors.initials: F
authors.lastname: Lohézic-Le Dévéhat
authors.forename: Sophie
authors.initials: S
authors.lastname: Tomasi
authors.forename: John A
authors.initials: JA
authors.lastname: Elix
authors.forename: Aurélie
authors.initials: A
authors.lastname: Bernard
authors.forename: Isabelle
authors.initials: I
authors.lastname: Rouaud
authors.forename: Philippe
authors.initials: P
authors.lastname: Uriac
authors.forename: Joël
authors.initials: J
authors.lastname: Boustie
mesh_terms: D000975:Antioxidants / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D001713:Biphenyl Compounds; D053630:Depsides / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D016166:Free Radical Scavengers / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D006576:Heterocyclic Compounds, 4 or More Rings / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D007214:Indonesia; D020128:Inhibitory Concentration 50; D007783:Lactones / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D015394:Molecular Structure; D010082:Oxepins / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D010851:Picrates / Q000494:pharmacology; D011794:Quercetin / Q000494:pharmacology; D013481:Superoxides / Q000494:pharmacology; D020949:Usnea / Q000737:chemistry*
chemical_list: D000975:Antioxidants; D001713:Biphenyl Compounds; D053630:Depsides; D016166:Free Radical Scavengers; D006576:Heterocyclic Compounds, 4 or More Rings; D007783:Lactones; D010082:Oxepins; D010851:Picrates; C522101:stictic acid; D013481:Superoxides; C000875:depsidone; D011794:Quercetin; C004931:1,1-diphenyl-2-picrylhydrazyl