title: Identification of radical scavenging compounds in Rhaponticum carthamoides by means of LC-DAD-SPE-NMR.
abstract: A hyphenated LC-DAD-SPE-NMR setup in combination with on-line radical scavenging detection has been applied for the identification of radical scavenging compounds in extracts of Rhaponticumcarthamoides. After NMR measurements, the pure compounds were infused into a mass spectrometer. The technique enabled selective detection and identification of individual radical scavenging compounds without any prior off-line chromatographic steps. Seven compounds, namely, quercetagetin-7-beta-glucopyranoside (1), quercetagetin-7-(6"-acetyl-beta-glucopyranoside) (3), 6-hydroxykaempferol-7-beta-glucopyranoside (2), 6-methoxykaempferol-3-beta-glucopyranoside (4), 6-hydroxykaempferol-7-(6"-acetyl-beta-glucopyranoside) (5), chlorogenic acid (6), and beta-ecdysone (7), were identified in ethanol or aqueous extracts. Compound 5 is a new natural compound. Its radical scavenging activity was tested against DPPH radical and was found to be weaker than that of the reference antioxidants rosmarinic acid and Trolox.
authors.affiliation: Laboratory of Organic Chemistry, Natural Products Chemistry Group, Wageningen University, Dreijenplein 8, 6703 HB Wageningen, The Netherlands.
authors.forename: Giedrius
authors.initials: G
authors.lastname: Miliauskas
authors.forename: Teris A
authors.initials: TA
authors.lastname: van Beek
authors.forename: Pieter
authors.initials: P
authors.lastname: de Waard
authors.forename: Rimantas P
authors.initials: RP
authors.lastname: Venskutonis
authors.forename: Ernst J R
authors.initials: EJ
authors.lastname: Sudhölter
mesh_terms: D001713:Biphenyl Compounds; D002839:Chromans / Q000494:pharmacology; D002934:Cinnamates / Q000494:pharmacology; D053630:Depsides; D016166:Free Radical Scavengers / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D043843:Leuzea / Q000737:chemistry*; D019906:Nuclear Magnetic Resonance, Biomolecular; D010851:Picrates / Q000494:pharmacology; D010946:Plants, Medicinal / Q000737:chemistry*; D000097123:Rosmarinic Acid
chemical_list: D001713:Biphenyl Compounds; D002839:Chromans; D002934:Cinnamates; D053630:Depsides; D016166:Free Radical Scavengers; D010851:Picrates; D000097123:Rosmarinic Acid; C004931:1,1-diphenyl-2-picrylhydrazyl; C010643:6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid