Extraction method for semen plantaginis polysaccharides

The invention discloses an extraction method for semen plantaginis polysaccharides. The method includes the following steps that firstly, semen plantaginis water extraction is performed; secondly, water extraction liquid is subjected to concentration and alcohol precipitation, and precipitate is obtained; thirdly, the precipitate is washed through anhydrous ethyl alcohol and acetone in sequence and then is redissolved in distilled water, protease is added for enzymolysis, and an enzymatic hydrolysis solution is obtained; fourthly, the enzymatic hydrolysis solution is subjected to dialysis for the first time for 24-72 hours through dialysis bags with the molecular weight being 80,000-200,000, reserved liquid is taken and subjected to dialysis for the second time for 24-72 hours through dialysis bags with the molecular weight being 1,500,000-2,000,000, exudate obtained during the second time of dialysis is subjected to concentration and alcohol precipitation, and precipitate is obtained through centrifuging; fifthly, the precipitate obtained in the fourth step is washed through anhydrous ethyl alcohol and acetone in sequence and then is redissolved in distilled water, activated carbon is added for decoloration, and the semen plantaginis polysaccharides is obtained after filtering and spray drying are performed. The prepared semen plantaginis polysaccharides have a remarkable immunity enhancement effect.