Vitexin

The extraction solvents ethanol, petroleum ether, ethyl acetate n-butanol and the dimethyl sulfoxide (DMSO) were supplied by Shanghai Chemical Reagent Corp. (Shanghai, China). The different standards used for the assays comprising gallic acid, rutin, ascorbic acid (Vit C), butylated hydroxytoluene (BHT), Trolox, 2,2-diphenyl-1-picrylhdrazyl (DPPH), 2,2′-azinobis-(3-ethyl-benzthiazoline-6-sulfonic acid) diammonium salt (ABTS), 2,4,6-Tri (2-pyridyl)-1,3,5-triazine (TPTZ), and indomethacin with a purity ≥99.5% were purchased from Sigma-Aldrich Corp (Shanghai, China). The HPLC grade solvents acetonitrile (ACN), methanol, and formic acid (FA) were obtained from TEDIA Company Inc. (Fairfield, OH, United States). The p-nitrophenyl α-D-glucopyranoside (p-NPG) substrate was acquired from Aladdin Bio-Chem Technology Corp. The COX-2 inhibitor screening assay kit (No: S0168) was purchased from Beyotime Biotechnology (Shanghai, China). The α-glucosidase enzyme was bought from Sigma Aldrich (St Louis, MO, United States) whereas Wuhan Antgene Biotechnology Co., Ltd. (Wuhan, China) supplied the COX-2 enzyme. The centrifugal ultrafiltration membranes 10 kDa Cut-off (YM-10) were purchased from Millipore Co. Ltd. (Bedford, MA, United States). Finally, Shanghai Macklin Biochemical Co. (Shanghai, China) supplied the phytochemical standards vitexin and astragalin (≥98%).