Spectronic 3000 array spectrophotometer

The Milton Roy Spectronic 3000 Array spectrophotometer (Rochester, Monroe, NY, USA) was used to record UV spectra, while IR spectra were obtained from the PerkinElmer FT-IR 1760X spectrophotometer (Boston, MA, USA). Mass spectra were determined using the Bruker MicroTOF mass spectrometer (ESI-MS) (Billerica, MA, USA). NMR spectra were recorded by the Bruker Avance DPX-300FT NMR spectrometer or the Bruker Avance III HD 500 NMR spectrometer (Billerica, MA, USA). Sigma Aldrich (Sigma-Aldrich, Dorset, UK) provided 2′,7′-dichlorofluorescein di-acetate (DCFH-DA), and Merck Millipore (Merck Millipore, Darmstadt, Germany) supplied fetal bovine serum (FBS). Invitrogen (Invitrogen Ltd., Paisley, UK) provided Dulbecco’s modified Eagle’s Medium/Nutrient Mixture F-12 Ham (DMEM/F-12), penicillin–streptomycin, H₂O₂, dimethyl sulfoxide (DMSO), and 3-[4,5-dimethyltiazol-2-yl]-2,5-diphenyl-tetrazolium bromide (MTT). Antibodies used in western blotting were obtained from Cell Signaling Technology (Danvers, MA, USA). Antioxidant enzyme assay test kits were obtained from Cayman Chemical (Cayman Chemical, Ann Arbor, MI, USA).

UV spectra were measured by a Milton Roy Spectronic 3000 Array spectrophotometer (Rochester, Monroe, NY, USA), and IR spectra by were measured by a PerkinElmer FT-IR 1760X spectrophotometer (Boston, MA, USA). Mass spectra were obtained from a Bruker MicroTOF mass spectrometer (ESI-MS) (Billerica, MA, USA). NMR spectra were recorded on a Bruker Avance DPX-300FT NMR spectrometer or a Bruker Avance III HD 500 NMR spectrometer (Billerica, MA, USA). Microtiter plate reading was analyzed by a Biochom EZ Read 400 microplate reader (Cambridge, UK). Optical rotation was measured by a PerkinElmer Polarimeter 341 (Boston, MA, USA). Vacuum liquid column chromatography (VLC) and column chromatography (CC) were performed on silica gel 60 (Merck, Kieselgel 60, 70–320 mesh), silica gel 60 (Merck, Kieselgel 60, 230–400 mesh) (Darmstadt, Germany) and Sephadex LH-20 (25–100 μm, Pharmacia Fine Chemical Co. Ltd.) (Piscataway, NJ, USA). Yeast α-glucosidase enzyme and p-nitrophenol-α-d-glucopyranoside were purchased from Sigma Chemical, Inc. (St. Louis, MO, USA), and acarbose was obtained from Fluka Chemical (Buchs, Switzerland).