Process for isolation of hepatoprotective agent silymarin from the seeds of the plant Silybum marianum

A process for extracting of hepatoprotective agent silymarin from the seeds of Silybum marianum (L) Gaertn, said process comprising:

• a) chilling the seeds of Silybum marianum at (−)20° C. by keeping overnight in a deep freezer/cold room,
• b) grinding the chilled seeds in a hammer mill fitted with 40 mesh discharge screen,
• c) extracting the powdered seeds in a soxhlet apparatus with a hydrocarbon solvent to remove all the fatty oil,
• d) percolating the defatted seed powder 3-4 times with acetonitrile at (20° C.-30° C.) for separating the silymarin containing fraction, as extract,
• e) removing the acetonitrile under vacuum in a wiped film evaporator to obtain a concentrate rich in silymarin, recovered acetonitrile being recycled to the process,
• f) drying the concentrate in a batch type stirred vacuum concentrator to obtain a product of semi solid consistency and its further drying in a vacuum oven to obtain a dry residue,
• g) stirring the powdered residue in cold dichloromethane (5° C.) and filtering in a closed vacuum filter for removing the impurities from silymarin rich solid product,
• h) dissolving the above solid in small amount of acetonitrile and precipitating silymarin by adding cold distilled water,
• i) filtering the light yellow precipitate and washing it three times with distilled water, and
• j) transferring the cake to a vacuum oven and drying it at 40-45° C., maintaining the oven pressure at 5-15 torr for 15 hours, and thereby obtaining pure silymarin.