Method for extracting 3,5-o-dicaffeoylquinic acid from huangshan gongju and its application in drugs for protecting against alcoholic liver damage

A method for extracting 3,5-O-dicaffeoylquinic acid from Huangshan Gongju, comprising:

• S1:
• crushing dried Gongju, and obtaining a Gongju extract liquid by ultrasonic assistance at 50-70° C. with ethanol as an extracting agent;
• S2:
• concentrating and drying the Gongju extract liquid to obtain a dry Gongju extract;
• and
• S3:
• using a preparative liquid chromatograph, where a mobile phase is a mixed system of solvent A and solvent B, with the solvent A being methanol and the solvent B being 0.1% formic acid in water;
• wherein the elution gradient is as follows:
• 0-40 minutes, the solvent A increases linearly from 30% to 70% by volume;
• 40-45 minutes, the solvent A increases linearly from 70% to 100% by volume;
• 45-50 minutes, the solvent A decreases linearly from 100% to 30% by volume;
• 50-55 minutes, the solvent A is maintained at 30% by volume;
• wherein a flow rate of the mobile phase is 10 mL/min;
• and obtaining the 3,5-O-dicaffeoylquinic acid.