Combination of LC−MS and LC−NMR as a Tool for the Structure Determination of Natural Products

Abstract

Application of both LC-MS and LC-NMR to a partially purified extract of Vernonia fastigiataled to the direct identification of antibacterial sesquiterpene lactones 1-9 without isolation of individual compounds. The rapid structural analysis of both major and minor components of this class of compounds demonstrated the power of structure-guided screening as a complementary method to assay-guided screening.

The online assignment of the absolute configuration of natural products: HPLC‐CD in combination with quantum chemical CD calculations

“…The hyphenation of high-performance liquid chromatography (HPLC) with spectroscopic methods such as NMR spectroscopy (HPLC-NMR) [1][2][3][4] and tandem mass spectrometry (HPLC-MS/MS) 3,5 has led to new strategies that do not only permit to differentiate between known and unknown compounds, but can even establish full constitutions and relative configurations of new natural products directly from the crude extract with a minimum amount of material. But with these methods alone, no information concerning the absolute configuration of the metabolites can usually be acquired-unless, e.g., by chromatography on a chiral phase, which, however, requires the availability of both enantiomers, their successful chromatographic resolution, and their secure stereochemical assignment.…”

Structural investigations on betacyanin pigments by LC NMR and 2D NMR spectroscopy

“…Since LC NMR experiments allow the rapid identification of natural products in extracts or pre-purified fractions without tedious isolation and especially the investigation of labile compounds (e.g. Bobzin et al, 2000;Bringmann et al, 2001;Cogne et al, 2003;Gavidia et al, 2002;Lindon et al, 2000;Setzer et al, 2003;Spring et al, 2001;Vogler et al, 1998), this technique was applied to the betalain enriched fraction of concentrated juice from red-violet pitaya H. polyrhizus (Weber) Britton & Rose in order to identify the individual betalains. Furthermore, the quality of the chromatographic separation for the subsequent isolation was proven.…”

Bioassay-coupled Chromatographic Analysis of Medicinal Natural Products: A Review

“…48 Attention is however still on the use of liquid chromatography nuclear magnetic resonance (LC-NMR) and LC-MS (mass spectrometry) for direct and rapid screening of medicinal plant extracts. 49 …”