Schisandrol b

Schisandra chinensis was obtained from the Yijishan Hospital of Wannan Medical College and was positively identified by Professor Lu Jianping of Wannan Medical College (Wuhu, China). Schisandrol B (>98% pure) was obtained from Shanghai Yuanye Biological Technology Co., Ltd. Internal standard (IS) bifendate (>98% pure) was procured from Shanghai Macklin Biochemical Co., Ltd (Shanghai, China). HPLC-grade formic acid, methanol, and methyl tert-butyl ether (MTBE; Merck, Germany) were used for the present study, as was analytical grade ammonium acetate. A Milli-Q water system (Millipore, USA) was employed for the preparation of diH₂O.

Authentic standards of ginsenoside Rg₁, ginsenoside Re, ginsenoside Rf, ginsenoside Rb₁, ginsenoside Rc, ginsenoside Rg₂, ginsenoside Rh₁, ginsenoside Ro, ginsenoside Rb₂ and ginsenoside Rd, schisandrol A, schisandrol B were all purchased from Shanghai yuanye Bio-Technology Co., Ltd. (Shanghai, China). d-Fructose was purchased from National Institutes for Food and Drug Control (Beijing, China). The purity of each chemical was equal to or greater than 97%. They were stored at 4 °C before use. P. ginseng, S. chinensis, and O. japonicus extract intermediates and SMI samples were from SZYY Group Pharmaceutical Limited (Nanjing, China).
All solvents, including methanol and acetonitrile with a purity of 98% were of chromatographic grade purchased from Fisher (Hampton, NH, USA), all other reagents and chemicals were of analytical grade.