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Stictic acid derivatives from the lichen Usnea articulata and their antioxidant activities
Françoise Lohézic-Le Dévéhat1, Sophie Tomasi, John A Elix
1Institut 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
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).
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