The invention belongs to the field of natural
organic chemistry, and relates to a method for preparing high purity silymarin by the following steps: adopting biological wall breaking and
microwave pretreatment to obtain oil, carrying out
microwave countercurrent extraction and
macroporous resin purification to obtain the high purity silymarin. The method has the following advantages that: 1, a step-by-
step method is adopted to carry out
degreasing, seeds are pretreated,
microwave countercurrent extraction is performed, and
isoelectric point precipitation is performed to remove proteins, such that complete
dissolution of effective components of the silymarin is prompted; 2, with the microwave extraction, the extraction time is reduced to 60-80 minutes so as to improve extraction speed and increase effective component content, and reduce
herb consumption and
energy consumption; 3, the
macroporous resin adsorption technology is adopted so as to reduce the amount of the
solvent, and the
macroporous resin can be conveniently and rapidly regenerated, such that the cost is substantially reduced; and 4, two products of
silybum marianum oil and silymarin can be obtained. With the method, the biological wall breaking treatment is performed on the
silybum marianum seeds at the early stage so as to shorten the microwave pretreatment time, such that the seed
oil can be extracted in just a few minutes; with the two-step microwave extraction, the extraction time is shortened; and the disadvantages of long conventional extraction time, low extract purity and single extract are overcome.