Phytochemical Profiling of Medicinal Herbs

Hyperoside (≥98.0%), quercetin (≥98.0%), astragalin (≥98.0%), kaempferol (≥98.0%), and isorhamnetin (≥98.0%) were supplied from National Institutes for Food and Drug Control (Beijing, China). Luteolin-7-O-glucoside (≥98.0%), isoquercitrin (≥98.0%), 4-caffeoylquinic acid (4-CQA) (≥98.0%), 3-caffeoylquinic acid (3-CQA) (≥98.0%), 4,5-dicaffeoylquinic acid (4,5-DiCQA) (≥98.0%), 3,4-dicaffeoylquinic acid (3,4-DiCQA) (≥98.0%), 3,5-dicaffeoylquinic acid (3,5-DiCQA) (≥98.0%), caffeic acid (CA) (≥98.0%), p-hydroxycinnamic acid (≥98.0%), and 5-O-feruloylquinic acid (5-FQA) (≥98.0%) were purchased from Shanghai Yuanye Bio-Technology Co., Ltd. (Shanghai, China). Their structures (shown in Figure 1) were fully explicated by spectra data (ESI-MS), which followed the methods of Zhang et al. [15 (link)].
Acetonitrile (MS grade) and formic acid (MS grade) were supplied from Thermo Fisher Scientific Inc. All the other chemicals of analytical grade were commercially available from Beijing Chemical Works (Beijing, China). Other reagents were of analytical grade. Deionized water for preparing samples was purified by MilliQ50 SP Reagent Water System (Bedford, MA, USA). Distillated water for mobile phase was purchased from A. S. Watson Group (Hong Kong) Ltd.