Thermo nicolet 6700 ft ir microscope instrument

A Rudolph Research Autopol III polarimeter was used for optical rotations (Rudolph Research Analytical, Hackettstown, NJ, USA). A Thermo Nicolet 6700 FT-IR microscope instrument was used for the IR spectra (Thermo Electron Corporation, Waltham, MA, USA). A TU-1900 ultraviolet spectrometer was used for the UV spectra (Beijing Persee General Instrument Co., Ltd., Beijing, China). For HR-ESI-MS, an Agilent-6210-LC/TOF mass spectrometer was used (Agilent Technologies, Inc., Santa Clara, CA, USA). For NMR, a Bruker Avance 600 spectrometer was used (Bruker Corporation, Billerica, MA, USA). An Agilent Xcalibur Atlas Gemini Ultra diffractometer was used for single-crystal X-ray diffraction (Agilent Technologies, Inc., Santa Clara, CA, USA). For melting points, the X-5 microscopic melting point apparatus was used (uncorrected) (Beijing Tech Instrument Co., Ltd., Beijing, China). MCI CHP 20P gel (75–150 μm, Tokyo, Japan), silica gel (300–400 mesh; Qingdao Marine Chemical Co., Ltd., Qingdao, China), ODS AQ C-18 gel (50 μm; YMC Co., Ltd., Kyoto, Japan), and Toyopearl HW-40F gel (Tosoh Corporation, Tokyo, Japan), were used for CC. Precoated GF254 silica gel plates (Qingdao Marine Chemical Co., Ltd., Qingdao, China) were used for thin layer chromatography. A SpectraMax Plus 384 microplate reader (Molecular Devices, San Jose, CA, USA) was used in the AGS and BGUS inhibition bioassays.

Optical rotations were measured on a Rudolph Research Autopol III polarimeter (Rudolph Research Analytical, Hackettstown, NJ, USA). IR spectra were obtained on a Thermo Nicolet 6700 FT-IR microscope instrument (Thermo Electron Corporation, Waltham, MA, USA). The UV spectra were obtained on a TU-1900 ultraviolet spectrometer (Beijing Persee General Instrument Co., Ltd., Beijing, China). HR-ESI-MS was performed on an Agilent-6210-LC/TOF mass spectrometer (Agilent Technologies, Inc., Santa Clara, CA, USA). The NMR spectra were obtained on a Bruker Avance 600 spectrometer (Bruker Corporation, Billerica, MA, USA). Silica gel (300–400 mesh; Qingdao Marine Chemical Co., Ltd., Qingdao, China), MCI CHP 20P gel (75–150 μm, Tokyo, Japan), ODS AQ C-18 gel (50 μm; YMC Co., Ltd., Kyoto, Japan), and Sephadex LH-20 gel (GE Healthcare, Uppsala, Sweden) were used for CC. Precoated GF254 Silica gel plates (Qingdao Marine Chemical Co., Ltd., Qingdao, China) were used for thin layer chromatography. Semi-preparative HPLC was carried out on an Agilent ZORBAX Eclipse XDB-C18 column (5 μm, 250 × 9.4 mm) with a Shimadzu LC-20AT system by eluting with CH₃OH/H₂O solvent system at 3 mL/min. A SpectraMax Plus 384 microplate reader (Molecular Devices, San Jose, CA, USA) was used in the AGS inhibition assay.