D xylose

Polygonatum sibiricum were purchased from a local market (Shenyang, Liaoning, China). HepG2 cell line was purchased from Stem Cell Bank, Chinese Academy of Sciences. DEAE-52 cellulose and Sephadex G-100 were obtained from Solarbio Co., Ltd (Beijing China). Monosaccharide standards (D-glucose, D-mannose, D-galactose, L-arabinose, D-xylose, L-rhamnose, and D-fucose) were purchased from Shanghai yuanye Bio-Technology Co., Ltd (Shanghai China). Fetal bovine serum (FBS), Dulbecco's Modified Eagle Medium (DMEM), trypsin EDTA, penicillin and streptomycin were obtained from Gibco (Grand Island, NY, USA). Caspase-3 and caspase-9 kit were purchased from KeyGEN Biotechnology Co., Ltd. (Jiangsu, China). All other chemicals were of reagent grade.

An Ultimate 3000 UPLC system (Thermo Fisher Scientific, USA) coupled with an electrospray ionization triple-quadrupole mass spectrometer (TSQ Endura, Thermo Fisher Scientific, USA) was used in this study. Chromatographic separation was carried out with an XAmide column (150 mm × 2.1 mm i.d., 5 μm) using an UltiMate 3000 HPLC system (Dionex, Sunnyvale, CA, USA). The column was kept at 40°C with a mobile phase of 0.1% formic acid (A) and acetonitrile (B) at a flow rate of 0.2 mL/min. Gradient elution began with 80% B and was then programmed as follows: 75% B from 0 min to 5 min, 60% B from 5 min to 10 min, and 85% B from 10 min to 20 min. MS detection was performed using a triple quadrupole mass spectrometer equipped with an electrospray ion source in positive and negative ionization modes.
The optimized mass spectrometric conditions were as follows: positive mode voltage, 3.5 kV; negative mode voltage, 2.5 kV; sheath gas flow, 35 arb; aux gas flow, 10 arb; ion transfer tube temperature, 325°C; vaporizer temperature, 275°C; and mass scan range, m/z 50–1000.
The sample spectra were compared with those of standards. Standards of maltotriose, α-D-lactose monohydrate, maltose, D-galactose, sucrose, D-(+)-xylose, D-glcNAc, rhamnose, D-fructose, D-(-)-arabinose, D-mannose, and D-(+)-glucose were purchased from YuanYe Biotechnology Company (Shanghai, China).