Abstract: The method of extraction total flavonoids from the leaves of Juglans mandshurica was optimized with the assistant of ultrasonic energy. The optimum extraction conditions of total flavonoids in J. mandshurica leaves were determined with orthogonal test. Four factors below were tested according to the extraction yield: ethanol concentration, extraction temperature, the ratio of material to solvent and extraction time. The optimum conditions of extracting were obtained as follows: 70% ethanol as extraction solvent at 50℃ for 20 min, and the ratio of solvent to material was 20:1 and the average extraction yield of total flavonoids from the leaves of J. mandshurica could be reached 4.458% under the optimum process.

Key words: Juglans mandshurica, total flavonoids, ultrasonic method, extraction process