[Extraction and separation of flavonoids from leave of Eucommia ulmoides in aqueous two-phase system]

To optimize the aqueous two-phase extraction and separation technology of flavonoids from the leaves of Eucommia ulmoides.

The system was prepared by dissolving suitable amounis of polyethylene glycol 4000 (PEG4000) and dextran 40000 ( D40) in aqueous solution. Phase map of the system, the mass fraction of PEG4000 and D40, the effects of amount of added sample, pH value and temperature on target compounds were investigated systematically.

The optimum extraction conditions were PEG4000 11%, N40 8%, 8 g sample which contains 6.85% of flavonoids, temperature 60 t and pH value 8. The highest extraction rate could reach to 75.82%.

This method has the advantages of mild conditions, solvent-free residues and less time-consumed, and the obvious efficiency in single-stage separation and purification of flavonoids.