Conventional sample enrichment strategies combined with high-performance liquid chromatography-solid phase extraction-nuclear magnetic resonance analysis allows analyte identification from a single minuscule Corydalis solida plant tuber.
Identification of putative biomarker molecules within the genus Corydalis (Papaveraceae) was pursued by combining conventional off-line sample enrichment with high-performance liquid chromatography-solid phase extraction-nuclear magnetic resonance (HPLC-SPE-NMR) based structure elucidation. Off-line reversed phase solid phase extraction (SPE) was used to enrich the desired analytes from a methanolic extract (93 mg dry weight) of a miniscule single tuber (233 mg dry weight) of C. solida. An aliquot of the SPE fraction (2.1 mg) was subjected to separation in the HPLC-SPE-NMR hyphenation. Chromatographic peaks bearing the metabolites under investigation were trapped in the SPE device in a single experiment and transferred to a 600 MHz NMR spectrometer equipped with a 30 microl cryofit insert fed into a 3 mm cryoprobe. Recorded homo- and heteronuclear 1D and 2D NMR data allowed the identification of the three analytes under investigation as protopine, allocryptopine, and N-methyl-laudanidinium acetate. The latter is a rare alkaloid, which has been isolated only once before.
Sturm
Sonja
S
Institute of Pharmacy/Pharmacognosy, Center of Molecular Biosciences, Leopold Franzens University Innsbruck, Innrain 52, A-6020 Innsbruck, Austria.
Seger
Christoph
C
Godejohann
Markus
M
Spraul
Manfred
M
Stuppner
Hermann
H
D000470:Alkaloids / Q000032:analysis* / Q000737:chemistry; D053119:Benzophenanthridines / Q000032:analysis / Q000737:chemistry; D001600:Berberine Alkaloids / Q000032:analysis / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D031311:Corydalis / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D015394:Molecular Structure; D035281:Plant Tubers / Q000737:chemistry*; D015203:Reproducibility of Results; D052616:Solid Phase Extraction / Q000379:methods*
D000470:Alkaloids; D053119:Benzophenanthridines; D001600:Berberine Alkaloids; C009093:protopine