ABSTRACT
Objective: To establish the methods for extraction and isolation of punicalagin from pomegranate peel, and further study the purification and quantification of punicalagin. Methods: Using an ultrasonic-assisted extraction method, punicalagin in pomegranate peel was extracted at room temperature by 50% ethanol with 20-fold volume of raw material. The content of punicalagin in the crude extract was determined by HPLC. To optimize the purification process of punicalagin, static adsorption and desorption experi-ments were employed to study five kinds of macroporous adsorbent resins (D101, A8-8, NKA-9, HPD-100 and HPD-500) for the one with the highest purification efficacy of punicalagin. In addition, the technical parameters of the macroporous adsorbent resin were opti-mized to obtain punicalagin with higher purity. Punicalagin was further separated and purified by using a reverse phase MCI GEL CHP20P column. Results:HPD500 resin showed the best ability to absorb and separate punicalagin in among five kinds of macro-porous adsorbent resins. The best technical parameters were as follows:the mass concentration of sample solution was 15 mg·ml-1 , the loading amount was 2BV, the pH was 2 and the eluting solvent was 8BV of 30% ethanol. With the best process as described a-bove, the content of punicalagin extracted from pomegranate peel increased from 10. 3% to 30. 7%. The obtained punicalagin could be further purified to 61. 3% from 30% in ethanol eluate by the reverse phase MCI GEL CHP20P column. Conclusion:HPD500 resin is the most effective in the purification of punicalagin from pomegranate peel, and the content of punicalagin can be dramatically increased after the purification by a reverse phase MCI GEL CHP20P column. The optimized process shows good reproducibility and stability.