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

J Chromatogr A. 2007 Sep 7;1163(1-2):138-44. doi: 10.1016/j.chroma.2007.06.029. Epub 2007 Jun 23.

Abstract

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.

MeSH terms

  • Alkaloids / analysis*
  • Alkaloids / chemistry
  • Benzophenanthridines / analysis
  • Benzophenanthridines / chemistry
  • Berberine Alkaloids / analysis
  • Berberine Alkaloids / chemistry
  • Chromatography, High Pressure Liquid / methods*
  • Corydalis / chemistry*
  • Magnetic Resonance Spectroscopy / methods*
  • Molecular Structure
  • Plant Tubers / chemistry*
  • Reproducibility of Results
  • Solid Phase Extraction / methods*

Substances

  • Alkaloids
  • Benzophenanthridines
  • Berberine Alkaloids
  • protopine