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Accurately weighed berberine hydrochloride dihydrate 1.0002 grams dissolved in 500mL of distilled water, dubbed berberine hydrochloride saturated solution; accurately weighed sodium chloride sodium sulfate 1.2007 grams, dissolved in 240mL anhydrous ethanol ; In the case of magnetic stirring, the solution of cholesterol sodium sulfate in ethanol was added dropwise to the saturated solution of berberine hydrochloride, and the molar ratio of berberine to <strong>[2864-50-8]sodium cholesteryl sulfate</strong> was 1: 1, stirring was continued for 30 minutes , Precipitate all precipitation, centrifugation, cleaning and collection of precipitation, freeze-drying that berberine <strong>[2864-50-8]cholesterol sulfate</strong> electrostatic complex.
General procedure: 0.01 mmol of each sterol was dissolved in anhydrous N,N-dimethylformamide (0.5 mL), and sulfurtrioxide-triethylaminecomplex (0.04 mmol) was added to the solution. The reaction mixture was stirredat 35 C under argon atmosphere for 1 h. After quenching by 0.2 mL MilliQ water, the mixture waspurified on silica gel column to remove the excess of triethylamine-sulfur trioxide. The resulting StSwas dissolved in MeOH and mixed with 0.5 g Dowex50WX8 in the sodium form. After stirring for 5 hat room temperature, the sample was filtrated on paper, and the process was repeated on the solution.Sodium salt of StS was dried by rotary evaporator as yellowish powder. Sample purification wasfinally achieved on analytical reversed-phase column (Phenomenex, C-18 Luna 4.6 250 mm, 100 A)using a gradient of CH3OH/H2O in agreement with Reference [17]. Elution was carried out by a flowrate of 1 mL min1, and StS were detected by an evaporative light-scattering detector (evaporationtemperature 45 C, nebulization temperature 60 C, N2 flow 1.4 mL min1). Pure products weresuspended in MeOH and diluted to obtain a MS sample of 5 g/mL. For the analysis, 5 L of thissolution was injected under the LC-MS conditions described below.