title: [Daviditin B from Swertia davidi Franch].
abstract: OBJECTIVE
  To study the active constituents of Swertia davidi Franch.
  
  
  METHODS
  Chemical components were isolated by column chromatography and their structures were established mainly by spectroscopic means (UV, IR, NMR, 2D-NMR, MS).
  
  
  RESULTS
  Three substances were identified as 2,5-dimethoxyl-1, 4-dicarboxyl benzene (VIII), 1,5,8-trihydroxyl-3,4-dimethoxyl xanthone (IX) and 1,8-dihydroxyl-3-(3'-hydroxyl-butoxy) xanthone (X).
  
  
  CONCLUSIONS
  Compounds VIII and IX were isolated from Swertia davidi Franch, for the first time, whereas compound X is a new xanthone, named daviditin B with antioxygenated activity in vitro.
authors.affiliation: School of Pharmaceutical Sciences, Central South University, Department of Pharmacy, Xiangya Hospital, Central South University, Changsha, China. tgs395@yahoo.com.cn
authors.forename: Gui-shan
authors.initials: GS
authors.lastname: Tan
authors.forename: Kang-ping
authors.initials: KP
authors.lastname: Xu
authors.forename: Fu-shuang
authors.initials: FS
authors.lastname: Li
authors.forename: Ping-sheng
authors.initials: PS
authors.lastname: Xu
authors.forename: Gao-yun
authors.initials: GY
authors.lastname: Hu
authors.forename: De-jian
authors.initials: DJ
authors.lastname: Jiang
authors.forename: Yuan-jian
authors.initials: YJ
authors.lastname: Li
mesh_terms: D000975:Antioxidants / Q000737:chemistry / Q000302:isolation & purification*; D008968:Molecular Conformation; D015394:Molecular Structure; D010946:Plants, Medicinal / Q000737:chemistry*; D029967:Swertia / Q000737:chemistry*; D044004:Xanthones / Q000737:chemistry / Q000302:isolation & purification*
chemical_list: C489701:1,8-dihydroxyl-3-(3'-hydroxyl-butoxy) xanthone; D000975:Antioxidants; D044004:Xanthones