Palmatine

Corydaline (151118), dehydrocorydaline (16051707), tetrahydropalmatine (151123), protopine (17062106), palmatine (140821), tetrahydroberberine (151111), columbamine (141108), berberine (141128), coptisine (140430), berberrubine (140407) and theophyline (17011102) with over 98% purity were purchased from Chengdu Pufei De Biotech Co. Ltd. (Chengdu, Sichuan Province, China). HPLC grade methanol and acetonitrile were purchased from Dikma Technologies Inc (Beijing, China). All other reagents including ethyl acetate, ether, dichloromethane and acetone belonged to analytical grade. Ultra-pure water was prepared by using a Milli-Q water purification system (Millipore, Molsheim, France). The blank plasma samples were achieved from the blood of healthy beagle dogs. Yuanhuzhitong tablet (20151201) was purchased from Sunflower Pharmaceutical Industry (Harbin, China). Corydalis yanhusuo W.T. Wang was obtained from the Panan Traditional Chinese Crude Drug Market, located in Zhejiang Province, China, and it was identified by Professor Zhenyue Wang of Heilongjiang University of Chinese Medicine in May, 2017.

Standards including puerarin, daidzin, coptisine, epiberberine, jatrorrhizine, berberine, palmatine, coumarin, daidzein, and cinnamic acid (purity >98%) were purchased from Chengdu Pufei De Biotech Co., Ltd. (Chengdu, China). The chemical structures of the abovementioned ten components are shown in Figure 1, respectively. Acetic acid and methanol (LC-MS grade) were obtained from Sigma-Aldrich (St. Louis, MO, USA) Inc. (CAS: 64-19-7; batch number: A6283) and ANPEL Laboratory Technologies (Shanghai) Inc. (CAS: 67-56-1; batch number: F2690144), respectively. Deionized water was prepared by the Milli-Q system (Millipore, Billerica, MA, USA).