title: DPPH radical scavenging and nitric oxide inhibitory activities of the constituents from the wood of Taxus yunnanensis.
abstract: The H2O, H2O/MeOH (1 : 1) and MeOH extracts of the wood of Taxus yunnanensis possessed significant DPPH radical scavenging and nitric oxide (NO) inhibitory activities. Chemical investigation of these extracts led us to isolation of nineteen compounds, i. e., five lignans, two simple phenolics, and twelve taxane-type diterpenes. Isotaxiresinol and seco-isolariciresinol, two major lignans of the wood, possessed potent DPPH radical scavenging activities with IC 50 values of 21.7 and 28.9 microM, respectively. Similarly, coniferyl aldehyde, taxusin, 10-deacetyltaxuyunnanine C, hongdoushan A, and 2alpha,5alpha,10beta-triacetoxy-14beta-[( S)-2-methylbutyryloxy]-4(20),11-taxadiene showed potent NO inhibitory activity with IC 50 values of 18.0, 22.1, 28.5, 15.0 and 26.4 microM, respectively, which were either equal or lower than the positive control NG-monomethyl- L-arginine ( L -NMMA) with an IC 50 value of 28.5 microM.
authors.affiliation: Institute of Natural Medicine, Toyama Medical and Pharmaceutical University, Toyama, Japan.
authors.forename: Arjun H
authors.initials: AH
authors.lastname: Banskota
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Tezuka
authors.forename: Nhan Trung
authors.initials: NT
authors.lastname: Nguyen
authors.forename: Suresh
authors.initials: S
authors.lastname: Awale
authors.forename: Takahiro
authors.initials: T
authors.lastname: Nobukawa
authors.forename: Shigetoshi
authors.initials: S
authors.lastname: Kadota
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D001713:Biphenyl Compounds; D004305:Dose-Response Relationship, Drug; D006801:Humans; D020128:Inhibitory Concentration 50; D008070:Lipopolysaccharides / Q000494:pharmacology; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D009569:Nitric Oxide / Q000037:antagonists & inhibitors* / Q000378:metabolism; D008517:Phytotherapy; D010851:Picrates; D010936:Plant Extracts / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D020946:Taxus; D014407:Tumor Cells, Cultured / Q000187:drug effects; D014934:Wood
chemical_list: D000975:Antioxidants; D001713:Biphenyl Compounds; D008070:Lipopolysaccharides; D010851:Picrates; D010936:Plant Extracts; D009569:Nitric Oxide; C004931:1,1-diphenyl-2-picrylhydrazyl