Silica gel h precoated plates

¹D- and ²D-NMR spectra were recorded in CD₃OD and acetone-d₆ with Bruker Avance III600 spectrometer (Bruker, Fällande, Switzerland) operating at 600 MHz for ¹H-NMR, and 150 MHz for ¹³C-NMR, respectively. Coupling constants are expressed in hertz (Hz), and chemical shifts are given on a δ (parts per million, ppm) scale with tetramethylsilane (TMS) as an internal standard. ESI mass spectra were recorded on a VG Auto Spec-300 spectrometer (Waters, Milford, MA, USA). Column chromatography (CC) was performed on Sephadex LH-20 (25–100 μm, GE Healthcare Bio-Science AB, Uppsala, Sweden), MCI-gel CHP20P (75–150 μm, Mitsubishi Chemical Co, Ltd., Tokyo, Japan), and Toyopearl HW-40F (Tosoh Co. Ltd., Tokyo, Japan). Thin-layer chromatography (TLC) was performed on silica gel H-precoated plates, 0.2–0.25 mm thick (Qingdao Haiyang Chemical Co., Qingdao, China), with benzene–ethylformate–formic acid (3:6:1 or 2:7:1, v/v), and compounds were detected by spraying with 2% ethanolic FeCl₃ and 10% sulfuric ethanol solution followed by heating.

2,2^׳-diphenyl-1-picrylhydrazyl (DPPH), 2,2-azino-bis-3- ethylbenzothiazoline-6-sulfonic acid (ABTS), N^G –Methyl-L-arginine acetate salt, 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox), and ascorbic acid were purchased from Sigma Aldrich (USA). Sephadex LH-20 (25–100 μm, GE Healthcare Bio-Science AB, Uppsala, Sweden), MCI-gel CHP20P (75–150 μm, Mitsubishi Chemical Co, Ltd., Tokyo, Japan), silica gel H-precoated plates, 0.2–0,25 mm thick (Qingdao Haiyang Chemical Co., Qingdao, China).