Application of HPLC‐NMR for the Rapid Chemical Profiling of a Southern Australian Sponge, Dactylospongia sp.

Abstract

Rapid chemical profiling of the antitumour active crude dichloromethane extract of the marine sponge, Dactylospongia sp. was undertaken. A combination of both offline (HPLC followed by NMR and MS) and on-line (on-flow and stop-flow HPLC-NMR) chemical profiling approaches was adopted to establish the exact nature of the major constituents present in the dichloromethane extract of this sponge. On-flow HPLC-NMR analysis was employed to initially identify components present in the dichloromethane extract, while stop-flow HPLC-NMR experiments were then conducted on the major component present, resulting in the partial identification of pentaprenylated p-quinol (5). Subsequent off-line RP semi-preparative HPLC isolation of 5 followed by detailed spectroscopic analysis using NMR and MS permitted the complete structure to be established. This included the first complete carbon NMR chemical shift assignment of 5 based on the heteronuclear 2-D NMR experiments, together with the first report of its antitumour activity. This study represents one of the few reports describing the application of HPLC-NMR to chemically profile secondary metabolites from a marine organism.

Application of HPLC-NMR in the Identification of Plocamenone and Isoplocamenone from the Marine Red Alga Plocamium angustum

“…The mass spectrometer was set to the electron impact (EI) mode with and a mass scan range between m/z 40 and 500. Analytical HPLC was performed as in reference [2], on a Phenomenex Gemini ODS (3) C 18 100Å 250 × 4.6 mm (5 µm) column with a flow rate of 1.0 mL/min unless specified. Semi-preparative HPLC analyses were performed on a Varian Prostar 210 (Solvent Delivery Module) equipped with a Varian Prostar 335 PDA detector (monitored at λ max 210 and 2 nm) and STAR LC WS Version 6.0 software, an isocratic solvent system (65% CH 3 CN/H 2 O) and a Phenomenex Prodigy ODS (3) 100Å C 18 250 × 10 mm (5 µm) column with a flow rate of 3.5 mL/min.…”

“…The application of HPLC-NMR has been demonstrated as being able to offer valuable insight into the structure class and the range of secondary metabolites present in a crude extract. This has been successfully demonstrated in a number of chemical profiling studies conducted within our research group both on marine and terrestrial extracts and also in monitoring chemical interconversions [1,2,3,4,5]. HPLC-NMR is advantageous in that it has the ability to separate components in situ and is a non-destructive technique.…”

A Historical Overview of Natural Products in Drug Discovery

“…In recent years the advances in microcoil HPLC-NMR and capillary NMR (CapNMR) has allowed for smaller quantities of samples to be analyzed in the order of 40–120 µL, this in combination with higher field magnets has greatly increased the sensitivity in profiling and dereplication natural product extracts [138,139,140]. Microcoil HPLC-NMR is generally suited for on-line HPLC-NMR typically where components present in higher concentrations in an extract are separated and analyzed in a conventional HPLC-NMR system using either on-flow, stop-flow or time slicing experiments [103,141,142,143]. Capillary NMR allows for the use of non-deuterated solvents in the off-line HPLC separation providing a broader range of solvents to be used and low costs.…”

Nuclear Magnetic Resonance Spectroscopy for Structural Characterization of Bioactive Compounds

“…They identified the antitumoral pentaprenylated p-quinol 54 as the major constituent in the dichloromethane extract of the marine sponge Dactylospongia sp. involving 1D ( 1 H, 13 C, and DEPT spectra) and 2D (COSY, HSQC, and HMBC spectra) NMR experiments [68]. Similar studies on the marine alga Laurencia filiformis led to the identification of the new potential antimicrobial compounds cycloisoallolaurinterol 55 and isoallolaurinterol 56 from their crude extract as well as the in situ monitoring of the chemical conversion between them [69] (Figure 7.24).…”