Qp 2010 gas chromatograph mass spectrometer ultra

Methanol extract of leaves, pseudostems, and rhizomes of Z. officinale were analyzed by GC-MS (Shimadzu QP-2010 Gas Chromatograph Mass Spectrometer Ultra), equipped by an autosampler AOC-20i and capillary column (SH-Rxi-5Sil MS) with the diameter 30 m × 0.25 mm × 0.25 μm. Helium was used as carrier gas (1.0 mL/min), with temperature injection of 250 °C; splitless mode; a column oven temperature of 70 °C at the beginning and held for 2 min, and then ramped to 200 °C at the rate of 10 °C/min and end temperature 280 °C and held for 9 min at the rate 5 °C/min; an MS ion source temperature of 200 °C, and an interface temperature of 280 °C, were set. The secondary metabolites were identified by comparing the experimental molecular mass spectra and base peak of each chromatogram with the Wiley and NIST database libraries.

TLC aluminium sheets 20 × 20 cm silica gel 60 F254, silica gel 60 (Merck, Darmstadt, Germany), and pre-coated TLC glass plates SIL G-25 UV254, 0.25 mm silica gel (Sigma, St. Louis, MO, USA) were used for thin layer chromatography analysis, vacuum liquid column chromatography, and preparative TLC, respectively. Spots on TLC were visualized by using spraying reagent of Liebermann Burchard for terpenoid/steroid detection. Shimadzu QP-2010 Gas Chromatograph Mass Spectrometer Ultra (Shimadzu, Kyoto, Japan) was used for GC-MS analysis. Acquity UPLC I-Class System with the XEVO G2-XS QTof Mass Spectrometer (Waters, Milford, MA, USA) was used for LC-MS/MS analysis, and NMR JEOL ECZ-500 and Variant Unity INOVA-500 Spectrometer (Agilent Technologies, Santa Carla, CA, USA) were used to elucidate the structural compounds. The nuclear magnetic resonance (NMR) was recorded at 500 MHz for ¹H and 150 MHz for ¹³C. Chemical shifts are given in δ (ppm) relative to TMS as internal standard, and deuterated chloroform was used as the solvent. The SARS-CoV-2 3CLpro #78042 assay kit was purchased from BPS Bioscience Inc., (San Diego, CA, USA).