Perkin elmer 341 polarimeter

The following apparatuses were applied to acquire isolations and physical parameters of compounds 1 and 2. Silica gel H (160–200 mesh, Shanghai Xibao Biological Technology Co. Ltd, Shanghai, China) was used in column chromatography. ODS (50 μm, Merck Co. Ltd., Darmstadt, Germany) and Sephadex LH-20 (GE Healthcare Bio-Sciences AB, Uppsala, Sweden) were taken as packing materials. High Performance Liquid Chromatography (HPLC) were carried out via a LC 3050 Analysis of HPLC system (CXTH, Beijing, China) assembled with an UV 3000 detector and a semi-preparative column (5 μm, 10 × 250 mm, YMC^® XB-C₁₈). High-resolution electrospray ionization mass spectra (HRESIMS) were performed using a Thermo Fisher LC-LTQ-Orbitrap XL spectrometer (Thermo Fisher Scientific Inc., Waltham, MA, USA). UV and IR spectra data were recorded by a Varian Cary 50 (Varian Medical Systems, Salt Lake City, UT, USA) and Bruker Vertex 70 (Brucker Corporation, Karlsruhe, Germany) apparatuses. A Bruker AM-600/400 spectrometer (Brucker Corporation) was implemented to afford NMR spectra. The chemical shifts of ¹H- and ¹³C-NMR were referenced to the solvent peaks for DMSO-d₆ at δ_H 2.50 and δ_C 39.5 and methanol-d₄ at δ_H 3.31 and δ_C 49.2. Optical rotation values were recorded by a Perkin-Elmer 341 polarimeter (Perkin Elmer Inc., Waltham, MA, USA).

TLC was carried out by silica gel 60 F254 (Shanghai Beinuo Biological Technology Co. Ltd., Shanghai, China). Sephadex LH-20 (GE Healthcare Bio-Sciences AB, Uppsala, Sweden), Silica gel (200–300 mesh; Shanghai Xibao Biological Technology Co. Ltd., Shanghai, China), and RP-18 (50 μm, Merck Co. Ltd., Darmstadt, Germany) were applied in column chromatography. Pseudomolecular ion peak was recorded by analyzing HRESIMS data through a Thermo Fisher LC-LTQ-Orbitrap XL spectrometer (Thermo Fisher Scientific Inc., Waltham, MA, USA). A Perkin-Elmer 341 polarimeter (Perkin Elmer Inc., Waltham, MA, USA) was performed to measure optical rotation. The UV and IR spectra were obtained by a Varian Cary 50 (Varian Medical Systems, Salt Lake City, UT, USA) and Bruker Vertex 70 instruments (Brucker Corporation, Karlsruhe, Germany), respectively. The NMR spectra were acquired using a Bruker AM-600/400 spectrometer (Brucker Corporation). The chemical shifts of ¹H- and ¹³C-NMR were referenced to the solvent peaks for methanol-d₄ at δ_H 3.31 and δ_C 49.2. HPLC procedures were carried out on a Dionex Ultimate 3000 (Thermo Fisher Scientific Inc.) applied with a UV detector and a semi-preparative column (5 μm, 10 × 250 mm, Welch Ultimate^® XB-C₁₈).

Optical rotations were determined using a Perkin-Elmer 341 polarimeter (PerkinElmer Co., Waltham, MA, USA). Ultraviolet (UV) spectra were taken on an UVmini-1240 spectrometer (Shimadzu Co., Kyoto, Japan) and HRESIMS spectra on an API QSTAR mass spectrometer (Applied Biosystem/MSD Sciex, Concord, ON, Canada). The ¹H, ¹³C, and 2D NMR spectra were recorded on a Bruker Avance-600 or a Bruker DRX-400 instrument using TMS as an internal standard. Column chromatography was performed on silica gel 60 (200–300 mesh, Qingdao Marine Chemical Ltd., Qingdao, China). For Preparative TLC plates (HSGF254, Jiangyou silicone Development Co., Ltd., Yantai, China), Sephadex LH-20 (GE Healthcare, Uppsala, Sweden) and Develosil ODS (50 μm, Nomura Chemical Co. Ltd., Osaka, Japan) were used.

Optical rotations were determined using a Perkin-Elmer 341 polarimeter (PerkinElmer Co., Waltham, MA, USA). Melting points were taken on a SGW X-4 micromelting point apparatus (INESA Physico Optical Instrument Co., Ltd., Shanghai, China) and HRESIMS spectra on an API QSTAR mass spectrometer (Applied Biosystem/MSD Sciex, Concord, ON, Canada). ECD spectra were recorded at 25 °C on a MOS-450/SFM300 spectrophotometer (Bio-logic, Claix, France). The ¹H, ¹³C, and 2D NMR spectra were recorded on a Bruker DRX-400 instrument using TMS as an internal standard. Column chromatography was performed on silica gel 60 (200–300 mesh, Qingdao Marine Chemical Ltd., Qingdao, China). Preparative HPLC was performed on a Waters 1525 Binary HPLC pump and a Waters 2414 refractive index detector using a YMC-Pack ODS-A column (250 mm × 10 mm I.D.; S-5 μm, 12 nm). For Preparative TLC plates (HSGF254, Jiangyou silicone Development Co., Ltd., Yantai, China), Sephadex LH-20 (GE Healthcare, Uppsala, Sweden) and Develosil ODS (50 μm, Nomura Chemical Co. Ltd., Osaka, Japan) were used.

IR spectra were recorded on a Thermo Nicolet Avatar FT-IR-750 spectrophotometer (Thermo, Tokyo, Japan) using KBr disks. Optical rotations were measured on a Perkin-Elmer 341 polarimeter (PerkinElmer, Inc. Suzhou, China). UV spectra were recorded on a Varian CARY 300 BIO spectrophotometer (Varian, Cary, NC, USA). The HR-ESI-MS and ESI-MS were taken on a Q-TOF Micro LC-MS-MS mass spectrometer (Waters Co, Milford, MA, U.S.A.). Nuclear magnetic resonance (NMR) spectra (400 MHz for ¹H and 100 MHz for ¹³C) were measured with a Bruker DRX-400 spectrometer (Bruker, Rheinstetten, Germany). HPLC analysis was performed on a preparative HPLC (Shimadzu LC-8 A, Shimadzu-C18, 5 μm, 250 × 20 mm inner diameter; 20 mL min⁻¹; 220/254 nm; Shimadzu, Kyoto, Japan) as well as a semipreparative HPLC (Agilent 1100, Zorbax SB-C18, 5 μm, 250 × 9.4 mm inner diameter; 1.5 mL/min; 220/254 nm; Agilent, Palo Alto, CA, USA). Column chromatography were consisted of silica gel (100–200 mesh, Qingdao Haiyang Chemical Group Co., Qingdao, China) as well as Sephadex LH-20 gel (GE Healthcare, Glies, UK), which were analyzed by thin-layer chromatography (TLC). TLC was performed on silica-gel plates (HSGF254, Yantai Chemical Industry Research Institute, Yantai, China) and the developed plates were observed under a UV lamp at 254 nm or by heating after spraying with sulfuric acid-ethanol, 5:95 (v/v).

Vacuum liquid chromatography (VLC) and column chromatography (CC) were performed on silica gel 60 (40–63 μm, Merck, Darmstadt, Germany), silica gel 60 (63–200 μm, Merck, Darmstadt, Germany) or Sephadex LH-20 (Pharmacia, Piscataway, NJ, USA) or Diaion HP20 (Mitsubishi Chemical, Tokyo, Japan). For preparative HPLC, a Shim-pack Prep-ODS (No.2025820) column (Shimadzu, Tokyo, Japan), with isocratic 50% methanol in water, SPD-10A UV-Vis detector (Shimadzu, Tokyo, Japan), and flow rate 1 mL/min, was used. NMR spectra were obtained with a Bruker Avance DPX-300 FT-NMR spectrometer (Brucker Corporation, Billerica, MA, USA). High-resolution electrospray ionization mass spectra (HR-ESI-MS) were recorded with a Bruker micro TOF mass spectrometer (Bruker Daltonics, Billerica, MA, USA). Optical rotations were obtained with a PerkinElmer 341 polarimeter (PerkinElmer, Boston, MA, USA). UV spectra were measured on an Agilent Technologies Cary 60 UV-Vis (Agilent, Santa Clara, CA, USA), and IR spectra (Agilent, Santa Clara, CA, USA) were recorded on a Perkin-Elmer FT-IR 1760x spectrophotometer (PerkinElmer, Boston, MA, USA). Yeast α-glucosidase enzyme, p-nitrophenol-α-D-glucopyranoside, and acarbose were purchased from Sigma Chemical, Inc. (St. Louis, MO, USA). Absorbance in 96-well plates was measured using a microplate reader (Wallac1420 Multilevel counter, Victor3, PerkinElmer).