Method for preparing high-purity danshinolic acid B from red sage root medicinal material

The invention provides a method for preparing high-purity danshinolic acid B from the red sage root medicinal material, comprising the following steps: Step 1, carrying out water extraction on the redsage root medicinal material under the ultrasonic condition and carrying out evaporation and concentration to obtain a concentrate; Step 2, extracting the concentrate with isopyknic n-butanol, and carrying out rotary evaporation on the extract liquor to obtain a water-soluble extract; Step 3, dissolving the water-soluble extract with 45-55% ethanol and spotting on a silica gel preparation plate for chromatography in a stripped sample application mode, placing in a chromatography cylinder and developing with a developing solvent, placing under a ultraviolet light at 254 nm for inspection, andscraping a purple fluorescence ribbon to obtain a danshinolic acid B crude product; and Step 5, dissolving the danshinolic acid B crude product with 45-55% ethanol, carrying out ultrasonic filtration,collecting a filtrate and