title: Phenolic derivatives with free-radical-scavenging activities from Ixeridium gracile (DC.) Shih.
abstract: Phytochemical investigation of the Tibetan medicinal plant Ixeridium gracile resulted in the isolation and identification of twelve flavonoids and two coumarins, compounds 1-14, the dimeric '2alpha,3alpha-epoxy-5,7,3',4'-tetrahydroxyflavan-(4beta-->8)-epicatechin' (1) being a new constituent. The free-radical-scavenging potentials of different extract fractions as well as of the pure compounds towards the DPPH (1,1-diphenyl-2-picrylhydrazyl) radical were evaluated, and are discussed in terms of structure-activity relationship (SAR). The flavonoids were found to be the major constituents contributing to the free-radical-scavenging activity of I. gracile, but the high concentration of coumarins additionally contributed to the observed activity.
authors: Key Laboratory for Natural Medicine of Gansu Province, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, PR China.
authors: Xue-Mei
authors: XM
authors: Ma
authors: Yong
authors: Y
authors: Liu
authors: Yan-Ping
authors: YP
authors: Shi
mesh_terms: D019659:Asteraceae / Q000737:chemistry*; D001713:Biphenyl Compounds / Q000737:chemistry; D003374:Coumarins / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology*; D005419:Flavonoids / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology*; D016166:Free Radical Scavengers / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology*; D006834:Hydrazines / Q000737:chemistry; D010636:Phenols / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology*; D010851:Picrates; D013329:Structure-Activity Relationship
chemical_list: D001713:Biphenyl Compounds; D003374:Coumarins; D005419:Flavonoids; D016166:Free Radical Scavengers; D006834:Hydrazines; D010636:Phenols; D010851:Picrates; C004931:1,1-diphenyl-2-picrylhydrazyl