Ammonium acetate

Acetone, n-hexane, ethyl acetate, concentrated sulfuric acid, sodium hydroxide, phosphoric acid, acetonitrile, ascorbic acid, methanol, formic acid, sodium acetate, acetic acid, hydrochloric acid, iron(III) chloride hexahydrate solution, ammonium acetate, were purchased from Guangzhou Chemical Reagent Factory (Guangzhou, China). phenolic compound standards [rutin (Rut), quercetin (Que), quercitrin (Quer), isoquercitrin (Iso), chlorogenic acid (ChA), syringic acid (SyA), ferulic acid (FeA), caffeic acid (CaA), resveratrol (Res), epicatechin (Epi), astragalin (Ast), scopoletin (Sco), galangal (Gal), catechuic acid (CatA), vanillic acid (VaA), benzoic acid (BeA), gallic acid (GaA), and protocatechuic acid (PrA)] were purchased from the National Institutes for Food and Drug Control (Beijing, China). 2,4,6-tris(2-pyridyl)-S-triazine (TPTZ), 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2ʹ-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS), and 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (trolox) were purchased from Sigma-Aldrich (St. Louis, MO, USA).

GA (assay 97.0%) was supplied by the China Resources Sanjiu Medical & Pharmaceutical (Shanghai, China). Ursolic acid (assay 99.2%, the internal standard [IS]) was purchased from the National Institutes for Food and Drug Control ([NIFDC], Guangzhou, China). Gal was synthesized by a non-aqueous enzymatic reaction in our laboratory. Egg phosphatidylcholine ([EPC], assay 98.0%) was purchased from Lipoid Co., Ltd. (Ludwigshafen, Germany). Cholesterol ([CH], assay 98%) was purchased from Advanced Vehicle Technology Pharmaceuticala. (Shanghai, China). Roswell Park Memorial Institute (RPMI)-1640 medium and trypsin solution (0.25%) were supplied by Thermo (Boston, MA, USA). Fetal bovine serum (FBS) was purchased from Hyclone (Logan, UT, USA). The hepatocellular carcinoma (HepG2) cell line was provided by the Institute of Biochemistry and Cell Biology, CAS (Shanghai, China). Methanol, ethanol, ammonium acetate, and ethyl acetate were purchased from Guangzhou Chemical Reagent Factory (Guangzhou, China) and were of at least analytical grade. HPLC or LC-MC/MS reagents were filtered through a 0.22μm filter before analysis. Methanol, ethanol, ethyl acetate, and the other reagents in liquid-liquid extraction were of analytical grade and used without further purification. Watsons’ water was used in all experiments.