Abstract: In this study, the two-phase extraction method was used to assist the extraction of total flavonoids and chlorogenic acid in Eucommia ulmoides Oliver. The optimal extraction process was determined by single factor and Box-Behnken response surface method test, and the total flavonoids and chlorogenic acid in Eucommia ulmoides extract were separated by ethanol/inorganic salt aqueous two-phase system. The results showed that under the optimal extraction conditions, the best aqueous two-phase extraction system for total flavonoids in Eucommia ulmoides was 50% ethanol content with 20% mass fraction of K₂HPO₄, the phase ratio R was 2.93 and the distribution ratio D was 10.35, and the extraction ratio could reach 77.94%. The best aqueous two-phase extraction system for chlorogenic acid was 60% ethanol with 20% K₂HPO₄ in water, the phase ratio R was 3.43 and the distribution ratio D was 12.32 with the extraction ratio up to 78.22%. The dual aqueous phase extraction technology with mild development conditions, stable phase and short time is great significant for the development and utilization of Eucommia ulmoides.

Key words: Eucommia ulmoides Oliver, total flavonoids, chlorogenic acid, aqueous two-phase system, purification