Abstract: High hydrostatic pressure extraction (HHPE) technique was used to extract flavonoids from Hawthorn leaves at normal temperature. The content of flavonoids was determined by UVspectrophotometry. Parameters that may influence the extraction process were investigated. Orthogonal test was applied to obtain the optimum extraction condition, which was as follows: solid dissolved in 50% ethanol, ratio of raw Hawthorn leaves (g) to solvent (ml) of 1∶45, temperature of 60 ℃, extraction pressure of 400 MPa and extraction time of 3 min. Results of this work show that HHPE possesses several advantages over other extraction methods, such as higher efficiency, shorter extraction time, and less impurity in the extracted flavonoids.

Key words: biological pharmacology, hawthorn leaves, flavonoids, high hydrostatic pressure extraction, orthogonal experimen