title: HPLC-NMR revisited: using time-slice high-performance liquid chromatography-solid-phase extraction-nuclear magnetic resonance with database-assisted dereplication.
abstract: Time-based trapping of chromatographically separated compounds onto solid-phase extraction (SPE) cartridges and subsequent elution to NMR tubes was done to emulate the function of HPLC-NMR for dereplication purposes. Sufficient mass sensitivity was obtained by use of a state-of-the-art HPLC-SPE-NMR system with a cryogenically cooled probe head, designed for 1.7 mm NMR tubes. The resulting (1)H NMR spectra (600 MHz) were evaluated against a database of previously acquired and prepared spectra. The in-house-developed matching algorithm, based on partitioning of the spectra and allowing for changes in the chemical shifts, is described. Two mixtures of natural products were used to test the approach: an extract of Carthamus oxyacantha (wild safflower), containing an array of spiro compounds, and an extract of the endophytic fungus Penicillum namyslowski, containing griseofulvin and analogues. The database matching of the resulting spectra positively identified expected compounds, while the number of false positives was few and easily recognized.
authors: Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
authors: Kenneth T
authors: KT
authors: Johansen
authors: Sileshi G
authors: SG
authors: Wubshet
authors: Nils T
authors: NT
authors: Nyberg
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods; D062313:Databases, Pharmaceutical; D006118:Griseofulvin / Q000032:analysis; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D010936:Plant Extracts / Q000032:analysis; D052616:Solid Phase Extraction / Q000379:methods*
chemical_list: D010936:Plant Extracts; D006118:Griseofulvin