title: [A study on DPPH free-radical scavengers from Xylaria nigripes].
abstract: The DPPH free-radical scavengers from the fungal Chinese medicine 'Wulingshen' (Xylaria nigripes) were studied. After separation using silica gel colunm chromatography, MPLC and HPLC, 20 DPPH free-radical scavengers with purity higher than 85% and yield more than 2 mg were screened, in which compound B4-16 had relatively higher yield and stronger free radical scavenging activity. The formula of compound B4-16 was determined to be C10H10O4 (MW: 194) based on its FAB-MS, 1H-NMR, 13C-NMR, 1H-13C HMBC, IR spectra, and its structure was elucidated. It was identical with 5,8-dihydroxy-3-methyl-3,4-dihydroisocoumarin. At the concentration of 20 mumol/L, its DPPH free\|radical scavenging activity was as 1.67 times as that of vitamin C or 2.10 times as that of Vitamin E.
authors.affiliation: College of Life Sciences, Zhejiang University, Hangzhou 310012, China.
authors.forename: G
authors.initials: G
authors.lastname: Wu
mesh_terms: D001203:Ascomycota / Q000737:chemistry*; D001713:Biphenyl Compounds; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D003374:Coumarins / Q000737:chemistry / Q000302:isolation & purification*; D016166:Free Radical Scavengers / Q000737:chemistry / Q000302:isolation & purification*; D049934:Isocoumarins; D010851:Picrates
chemical_list: C488395:5,8-dihydroxy-3-methyl-3,4-dihydroisocoumarin; D001713:Biphenyl Compounds; D003374:Coumarins; D016166:Free Radical Scavengers; D049934:Isocoumarins; D010851:Picrates; C004931:1,1-diphenyl-2-picrylhydrazyl