Abstract: A new method for the extraction and separation of polydatin from Polygonum cuspidatum was developed.Polydatin was extracted by ultrasonic extraction with temperature-sensitive PE6400 as extraction solvent.The effects of the concentration of PE6400,extraction duration,times of extraction and solid-liquid ratio on the extraction yield of polydatin were investigated.The optimal extraction conditions were 8% PE6400 as extraction solvent,1:25 as solid-liquid ratio and ultrasonic extraction for 2 times,each time for 30 min.The extraction yield of polydatin reached 17.74 mg/g under the optimized conditions.In the process of enrichment and separation,the allocation behavior of polydatin in the temperature-induced aqueous two-phase system were also tested under different pHs,different solid-liquid ratios.When the solid-liquid ratio was 1:11,the pH of buffer solution was 12 and heated at 90 ℃water bath for 45 min,83.3% of polydatin was allocated in the aqueous phase.The developed method was convenient,efficient and easy to operate.It had high extraction rate and low toxicity to the environment.

Key words: polydatin, temperature-induced, aqueous two-phase, HPLC