Bifendate

The ZGI, DGE, AGE, RMU, HDA and APS, the purities of which were more than 98%, were refined in our laboratory (identified by NMR and MS). Bifendate (lot: 73536-69-3; purity > 98%, IS) was purchased from Chengdu Must Bio-Technology (Chengdu, Sichuan province, China). Methanol and acetonitrile (HPLC-grade) were obtained from J & K Medical (Beijing, China). Ammonium acetate was purchased from Kermel (Tianjin, China). Ultra-pure water was gained by using Milli-Q water purification system (Millipore, Molsheim, France). All other reagents including ethyl acetate, ether and dichloromethane were of analytical grade. The plasma samples were obtained from the blood of rat.
The S. officinalis was collected from the Anguo Traditional Chinese Medicine Market of Hebei and authenticated by Professor Zhenyue Wang of Heilongjiang University of Chinese Medicine in September 2016. A voucher specimen was deposited in Pharmaceutical Research Department of Harbin Medical University, China.

Reference standards of purpurin, munjistin, and mollugin were isolated from R. cordifolia and identified by our laboratory. On the basis of UV, MS, NMR and HPLC analysis, the chemical structures and the purities (purity ≥ 98%) of isolated reference standards were confirmed. Bifendate (Lots: 100192-200503) was purchased from Chengdu Must Bio-Technology Co., Ltd. (Chengdu, Sichuan, China) and used as an internal standard (I.S.).
The following solvents and chemicals were used in our experiments: J & K Medical (Beijing, China) provided the HPLC-grade methanol (MeOH) and acetonitrile (CH₃CN). HPLC-grade ammonium acetate was purchased from DIKMA Technologies (Beijing, China). All other reagents were of analytical-grade. Ultrapure water was prepared using a Milli-Q water purification system (Millipore, Molsheim, France).
The dried roots and rhizomes of R. cordifolia were obtained from Bozhou (Anhui, China), the largest Chinese herbal medicine distribution center in the world, and were identified by Professor Zhenyue Wang in Heilongjiang University of Chinese Medicine. A voucher specimen (Art. No. 20160001) was deposited in the College of Pharmacy, Harbin Medical University, China.