Application of ultrasonic technique for extracting chlorogenic acid from Eucommia ulmodies Oliv. (E. ulmodies)

An ultrasonic method for the extraction of chlorogenic acid from fresh leaves of Eucommia ulmodies Oliv. was investigated and optimized. The influence of four extraction variables on extraction efficiency of chlorogenic acid was investigated. The optimum extraction conditions found were: 70% aqueous methanol; solvent: sample ratio=20:1 (v/w); extraction time 3 x 30 min. The recovery of chlorogenic acid was studied (HPLC) and the reproducibility of the extraction method was determined. The optimized ultrasonic extraction conditions were applied to extract chlorogenic acid from fresh leaves, fresh bark and dried bark of E. ulmodies and four traditional Chinese medicines. The application of sonication method was shown to be highly efficient in the extraction of chlorogenic acid from E. ulmodies and other Chinese medicines compared with classical methods.