Method for preparing chlorogenic acid in Eucommia ulmoides leaves

The invention discloses a method for preparing chlorogenic acid in Eucommia ulmoides leaves, which comprises the following steps of: crushing the Eucommia ulmoides leaves, performing warm water extraction assisted by cellulose, performing conventional filtration, removing impurities by using an ultrafiltration membrane, performing nanofiltration and concentration, separating and purifying by using macroporous resin, and concentrating and drying to obtain chlorogenic acid powder. The chlorogenic acid in the Eucommia ulmoides leaves is subjected to warm water extraction assisted by cellulose, the extraction rate can reach 95 percent, the water extraction temperature is lower, and the extraction time is shortened; the ultrafiltration membrane is adopted to remove the impurities from the extracting solution and separate other byproducts, the membrane operating process is simple, the membrane flux can be stable for a long time, and the membrane is easy to clean, has long service life and is suitable for industrial