Silica gel 60

Optical rotations were obtained with a Perkin-Elmer 341 polarimeter (Boston, MA, USA). UV spectra were measured on a Milton Roy Spectronic 300 Array spectrophotometer, and IR was recorded on a Perkin-Elmer FT-IR 1760x spectrophotometer (Boston, MA, USA). High-resolution electrospray ionization mass spectra (HR-ESI-MS) were recorded with a Bruker micro TOF mass spectrometer (Billerica, MA, USA). NMR spectra were obtained with a Bruker Avance DPX-300 FT-NMR spectrometer (Billerica, MA, USA). Vacuum liquid chromatography (VLC) and column chromatography (CC) were performed on silica gel 60 (Merck, 70–230 µm, Darmstadt, Germany), silica gel 60 (Merck, 230–400 nm) or Sephadex LH-20 (Pharmacia, Piscataway, NJ, USA). Yeast α-glucosidase enzyme, p-nitrophenol-α-d-glucopyranoside, pancreatic lipase, and 4-methylumbelliferyl oleate were purchased from Sigma Chemical, Inc. (St. Louis, MO, USA), and acarbose from Fluka Chemical (Buchs, Switzerland).

Synthesis. All chemicals used were of reagent grade. Yields refer to purified products and are not optimized. Merck silica gel 60 (230−400 mesh) was used for column chromatography. Merck TLC plates and silica gel 60 F254 were used for TLC. NMR spectra were obtained with a Bruker 400 AVANCE spectrometer in the indicated solvents. Melting points were determined in open capillaries in a Gallenkamp apparatus and were uncorrected. The chemical shifts are referenced to the residual not deuterated solvent signal (CHD₂OD: δ (¹H) = 3.31 ppm, δ (¹³C) = 49.86 ppm). The values of the chemical shifts are expressed in ppm, and the coupling constants (J) in Hz. An Agilent 1100 LC/MSD operating with an electrospray source was used in mass spectrometry experiments. The purity of compounds 1b–h was assessed by RP-HPLC (Agilent 1100 series) and was found to be higher than 95% [40 (link)]. A Zorbax Eclipse XDB-C8 column (4.6 × 150 mm, 5 μm) was used in the HPLC analysis with methanol-H₂O (0.1% formic acid) (80:20) as the mobile phase at a flow rate of 0.5 mL/min. UV detection was achieved at 280 nm. The absorption spectra were recorded with a PerkinElmer Lambda 900 in the indicated solvent. UV-B irradiations were conducted using a Multyrays chamber equipped with 2 GT15T8 Hg UV-B tubes (2 × 15 Watt) in continuous rotation.

Organic solvents were obtained from Merck, Germany; Diclofenac was purchased from Beximco Pharma, Bangladesh; Aspirin was purchased from Square Pharmaceutical Ltd, Bangladesh; Thin Layer Chromatography (TLC) was run on Merck TLC plates precoated with Si₆₀ F₂₅₄ with visualization by spraying with 10 % H₂SO₄ in MeOH followed by heating. VLC was done using Silica gel 60 (0.040–0.005 mm), Merck, Germany. Open column chromatography was done by using Silica gel 60 (0.063–0.020 mm), Merck, Germany. The IR Spectrum was obtained using a Shimadzu IR Prestige-2 FT-IR while the ¹H-NMR spectra were recorded on an ultra shield Bruker DPX 400 spectrometer. The NMR spectra were recorded running gradients and using residual solvent peak (δ 7.25 s for ¹H-NMR) as an internal reference.

Rhenium-oxo meso-triarylcorroles, Re[TpXPC](O), were synthesized as previously reported^{50 (link)}. Chlorine gas (Cl₂), liquid bromine (Br₂), benzene, and chloroform were purchased from Sigma-Aldrich. Silica gel 60 (0.04–0.063 mm particle size, 230–400 mesh, Merck) was used for flash chromatography and Silica gel 60 preparative thin-layer chromatography (PTLC) plates (20 cm × 20 cm, 0.5 mm thick; Merck) were used for final purification of all complexes.

Organic solvents for extraction and chromatographic separation were obtained from Active Fine Chemicals, Bangladesh. Melting points were determined on a digital melting point Apparatus of Cole-Parmer Ltd., UK (model SMP10). Thin layer chromatography (TLC) was run on Merck pre-coated TLC plates with Si₆₀F₂₅₄. Plates were visualized by spraying with Lieberman–Burchard reagent followed by heating. Vacuum Liquid chromatography was done using Silica gel 60 (0.040–0.005 mm), Merck, Germany. Open column chromatography was performed using Silica gel 60 (0.063–0.020 mm), Merck, Germany. Spectral data were obtained as follows: Infrared (IR) spectrum with a Shimadzu IR Prestige-2 FT-IR spectrophotometer, ultraviolet spectrum with a Shimadzu UV spectrophotometer (UV-1800), nuclear magnetic resonance (NMR) spectra with an ultra-shield Bruker Avance 400 MHZ in CD₃OD. The NMR spectra were recorded running gradients and using residual solvent peak (at 3.33 in ¹H-NMR and middle peak of septate at 49.0 in ¹³C-NMR) as internal reference.

Plant materials: Roots of Dipsacus japonicus (DJ) were bought in the Lan Ong market (traditional herb market) of Hanoi, Vietnam in May 2016. The species was identified by botanist Dr. Nguyen Van Tap, National Institute of Medical Materials, Hanoi. Method: Comparison of plant morphology with an authentic voucher specimen. A voucher specimen (Nr. ICH 2016) is deposited in the Institute of Chemistry, VAST, Hanoi.
HR ESI MS spectrum was obtained on a QStar Pulsar (Applied Biosystems). ¹H NMR (500.13 MHz) and ¹³C NMR (125.77 MHz) spectral data were measured on a Bruker Avance 500 NMR spectrometer at 25 °C. Chemical shifts were expressed in δ (ppm) downfield from as CD₃OD (¹H = δ_H 3.31, 4.78; ¹³C = δ_C 49.1), and coupling constants were reported in Hertz (Hz). Silica gel 60 F-254 (0.25 mm, Merck); reversed phase RP₁₈ F254S (0.25 mm, Merck). CC: Silica gel 60 (230–400 mesh, Merck) for the first column, Silica gel 60, 40–63 µm (Merck) and Sephadex LH-20 for the following columns. The purity of compound 1 was estimated to be greater than 95% by integration in ¹H and ¹³C NMR.