Metabolite Profiling of Seaweed Extracts using NMR Spectroscopy

Five hundred microliters of methanol-d4, 400 μL of 0.2 M phosphate buffer solution (0.2 M of sodium hydrogen phosphate, 0.2 M sodium dihydrogen phosphate in D₂O, pH 7.0 ± 0.1), and 100 μL of 5 mM TSP (3-trimethylsilyl propionic-2, 2, 3, 3-d4 acid sodium salt) were added into an Eppendorf tube containing 50 ± 0.5 mg of each seaweed extract. ¹H-NMR experiments were carried out on Ascend 800 MHz, Avance III HD Bruker spectrometer (Bruker Biospin AG, Fällanden, Switzerland) equipped with 5 mm CPTIC ¹H-¹³C/15 N/D Z-GRD Z119427/0011 cryogenic probe. ¹H-NMR spectra were processed and analysed using Chenomx NMR Suite 8.4 (Chenomx, Edmonton, AB, Canada). All ¹H-NMR spectra were calibrated, phased and baseline-corrected manually using the processor module of Chenomx NMR Suite. The concentration and profiling of metabolites were estimated using the profiler module of Chenomx NMR Suite. The detail procedures of such analyses has been reported in a previous article Choi et al.^{23 (link)}.