Study on separation and purification of oligomeric proanthocyanidin from Rhodiola rosea

The objective was to study the technology for the separation and purification of oligomeric proanthocyanidins from Rhodiola rosea and establish the best operating conditions. First, the oligomeric proanthocyanidins was extracted by ethyl acetate from rough-extracted R. rosea liquid using an optimized technique. Its purification was achieved by macroporous resins. Five kinds of macroporous adsorbent resins were compared for the adsorption and desorption performance of procyanidins, the concentration and pH value of both the extracted sample and the eluant were investigated. According to the results, the optimized conditions were as follows: four times of extraction at 25 min each time was effective, the best volume ratio was 1.5:1 (ethyl acetate: extracted solution); AB-8 resin was the best choice; the concentration of the extracted sample was 4.0 g/L, and the pH was 4.5; the ratio of the diameter to height of the chromatography column was 1:40 (cm); 50% ethanol was used as the eluant at pH 5; and finally, the purity of procyanidins reached 88. 3%.