Method for extraction of salvianolic acid B from stems, leaves and flowers of salvia miltiorrhiza

The invention provides a method for extraction of salvianolic acid B from stems, leaves and flowers of salvia miltiorrhiza. The method includes: crushing stems, leaves and flowers of salvia miltiorrhiza, then performing ultrasonic extraction in a weak acid aqueous solution of organic acid under an ice water bath environment, conducting flocculation sedimentation filtration and two-aqueous phase extraction to remove impurities, then carrying out extraction enrichment with a mixed organic solvent, and conducting silica gel column chromatography and recrystallization under a shade room temperature condition to obtain salvianolic acid B with a content up to 98% or above. The method utilizes the waste stems, leaves and flowers of salvia miltiorrhiza herb to prepare high purity salvianolic acidB, develops new drugs, simplifies the process, recycles most of the organic solvents, reduces the environmental pollution of stems, leaves and flowers of salvia miltiorrhiza, organic solvent and resinwaste, lowers the cost, a