Data for: 1H NMR spectroscopy-based metabolic profiling of Ophiocordyceps sinensis and Cordyceps militaris of water-boiled and 50% ethanol-soaked extracts
Sample preparation for NMR Previously stored O. sinensis and C. militaris were divided into two groups and used for 1H NMR sample preparation. Prior to NMR analysis, O. sinensis and C. militaris were thawed to room temperature. For the 50% water:ethanol (H2O:EtOH) group, 5 mL of the 50% water:ethanol mixture was added to 500 mg O. sinensis or C. militaris and vortexed for 60 s. The mixtures were maintained for 360 days at 25oC. For the water (H2O) group, 5 mL of distilled water was added to 500 mg of O. sinensis or C. militaris. The mixtures were placed in boiling water and heated to 100oC for 30 mins. The extracts were centrifuged (15 min, 13,000 rpm) at 4oC and 3 mL of supernatant was collected. The supernatant was frozen at -80oC and then dried using a vacuum centrifugal evaporator (CHRiST, Alpha 2-4/LSC, Germany). The dried residues were separately dissolved in 3 mL of distilled water. A 600 µL extract was filtered (Millipore Amicon® ULTRA 3 kDa) and filtrates were collected. 3-(Trimethylsilyl) propanesulfonic acid (50 µL) pre-dissolved in D2O (an internal standard) was subsequently added to 450 µL of the filtrates. Finally, aliquots (480 µL) of each extract were transferred to a 5 mm NMR tube (Norell, Morganton, NC, USA) for NMR analysis. The 1H NMR spectra were recorded as detailed below. NMR analysis and data preprocessing All of the 1H NMR spectra were acquired at 298 K on a Bruker AV III 600 MHz NMR spectrometer (Bruker Analytische GmbH, Rheinstetten, Germany) equipped with an inverse cryoprobe operating at a proton NMR frequency of 600.13 MHz. For each sample, other used acquisition parameters were as follows: number of scans = 32, spectral width (SW) = 8,000 Hz, pulse width (PW) = 10 s, and relaxation delay = 1.0 s. A Noesygppr1d pulse sequence was applied to suppress the residual water signal. All of the free induction decay NMR spectra were phased and baseline-correction was performed using Chenomx NMR Suite v.7.7 (Chenomx Inc., Edmonton, Canada). The metabolites were identified by matching spectral signals to the Chenomx 600 MHz Library comprising 330 metabolites. A reference compound DSS-d6 was used as an internal standard for the chemical shifts (set to 0 ppm) and a reference signal for the quantification. Data quantification was performed by comparing the integration of a known reference signal (DSS-d6) with the signals derived from a library of compounds containing chemical shifts and peak multiplicities for all of the resonances of the constituents. The results were exported as an Excel file for further analysis.