Standards of chrysophanol, emodin, aloe-emodin, rhein, physcion, questin, TSG, emodin-8-O-β-D-glucoside (EG), physcion-8-O-β-D-glucoside (PG), and puerarin (IS) were purchased from the Chengdu Chroma-Biotechnology Co., Ltd. (Chengdu, China). Citreorosein, questinol, torachrysone-8-O-glucoside (TG), and chrysophanol-8-O-β-D-glucoside (CG) were purchased from the Qingdao Advancechem Technology Co., Ltd. (Qingdao, China). The chemical structures of the 13 constituents of RPM and IS are shown in Figure 1 .
RPM was purchased from Beijing Tongrentang Pharmaceutical Co., Ltd, and identified by professor Shuofeng Zhang (Beijing University of Chinese Medicine). The voucher specimen (lot no.: YDZY-HSW-20180521) was deposited at 4°C in our laboratory. The RPM (200 g) was refluxed with 70% ethanol twice (1 : 10, w/v), 3 h for each time. All the solution obtained were put together and condensed by vacuum drier at 50°C to get 50 ml extract, containing 4 g raw herb per milliliter.
LC-grade acetonitrile and formic acid were purchased from Honeywell (Morristown, USA) and Roe Scientific Inc. (Newark, USA), respectively. Ultra-pure water was prepared using a Millipore Milli-Q purification system (Bedford, USA).
RPM was purchased from Beijing Tongrentang Pharmaceutical Co., Ltd, and identified by professor Shuofeng Zhang (Beijing University of Chinese Medicine). The voucher specimen (lot no.: YDZY-HSW-20180521) was deposited at 4°C in our laboratory. The RPM (200 g) was refluxed with 70% ethanol twice (1 : 10, w/v), 3 h for each time. All the solution obtained were put together and condensed by vacuum drier at 50°C to get 50 ml extract, containing 4 g raw herb per milliliter.
LC-grade acetonitrile and formic acid were purchased from Honeywell (Morristown, USA) and Roe Scientific Inc. (Newark, USA), respectively. Ultra-pure water was prepared using a Millipore Milli-Q purification system (Bedford, USA).