title: Discovering new natural products directly from crude extracts by HPLC-SPE-NMR: chinane diterpenes in Harpagophytum procumbens.
abstract: HPLC-SPE-NMR experiments with crude extracts of Harpagophytum procumbens allowed the rapid identification of novel, unstable chinane-type tricyclic diterpenes (1 and 2), along with numerous other constituents. Dramatic sensitivity gains achieved with this novel hyphenated technique establish a new paradigm in natural products research: rapid and rigorous structure determination of multiple extract components, including minor components, without preparative-scale isolation.
authors.affiliation: Department of Medicinal Chemistry and Department of Pharmaceutics and Analytical Chemistry, The Danish University of Pharmaceutical Sciences, Universitetsparken 2, DK-2100 Copenhagen, Denmark.
authors.forename: Cailean
authors.initials: C
authors.lastname: Clarkson
authors.forename: Dan
authors.initials: D
authors.lastname: Staerk
authors.forename: Steen Honoré
authors.initials: SH
authors.lastname: Hansen
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Smith
authors.forename: Jerzy W
authors.initials: JW
authors.lastname: Jaroszewski
mesh_terms: D002851:Chromatography, High Pressure Liquid; D004224:Diterpenes / Q000737:chemistry / Q000145:classification / Q000302:isolation & purification; D031684:Harpagophytum / Q000737:chemistry*; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D010936:Plant Extracts / Q000737:chemistry*; D018517:Plant Roots / Q000737:chemistry; D013019:South Africa
chemical_list: C510528:12,13-dihydroxychina-8,11,13-trien-7-one; C510529:6,12,13-trihydroxychina-5,8,11,13-tetraen-7-one; D004224:Diterpenes; D010936:Plant Extracts