Direct ¹³C NMR Detection in HPLC Hyphenation Mode: Analysis of Ganoderma lucidum Terpenoids

Abstract

Solid phase extraction (SPE) was introduced as a crucial step in the HPLC-SPE-NMR technique to enable online analyte enrichment from which proton-detected NMR experiments on submicrogram amounts from complex mixtures were possible. However, the significance of direct-detected (13)C NMR experiments is indubitable in simplifying structural elucidations. In the current study, we demonstrated direct (13)C NMR detection of triterpenoids from a Ganoderma lucidum extract in hyphenation mode. The combined advantage of a cryogenically cooled probe, miniaturization, and multiple trapping enabled the first reported application of HPLC-SPE-NMR analysis using direct-detected (13)C NMR spectra. HPLC column loading, accumulative SPE trappings, and the effect of different elution solvents were evaluated and optimized. A column loading of approximately 600 μg of a prefractionated triterpenoid mixture, six trappings, and an acquisition time of 13 h resulted in spectra with adequate signal-to-noise ratios to detect all C-13 signals.

Triterpenes and Meroterpenes with Neuroprotective Effects from Ganoderma leucocontextum

“…Ganoleucoin R (2) possessed a molecular formula of C 30 H 44 O 8 by HR-TOF-MS data. The 1 H-NMR and 13 C-NMR spectroscopic data exhibited signals due to six Me groups, eight CH 2 groups including one O-bearing CH 2 Table 1). The 1 H-and 13 C-NMR spectra of 2 resembled with those of 12 except for the absence of one singlet Me group and an O-bearing CH group, the presence of one O-bearing CH 2 group (d(C) 65.6), and an extra ketone moiety (d(C) 217.4, C(3)).…”

Polysaccharides from Ganoderma lucidum attenuate microglia-mediated neuroinflammation and modulate microglial phagocytosis and behavioural response

“…In recent years, the extract of Ganoderma lucidum (GL) has been isolated [3–5] and frequently used in medications as well as in dietary supplements. The constituents of GL include mainly ergosterol, triterpenoids, unsaturated fatty acids and polysaccharides.…”

Molecular Networking as a Dereplication Strategy

“…3 Current dereplication strategies include hyphenated techniques, such as HPLC-MS, HPLC-NMR, HPLC-NMR-MS, and HPLC-SPE-NMR, 4-6 or bioactivity fingerprints, such as cytological profiling or BioMAP. 7,8 The common denominator of these strategies is the attempt to exploit the fact that structurally similar or identical molecules share similar physical characteristics, such as UV-vis profiles, chromatographic retention times, MS, NMR chemical shifts, or biological properties.…”