Ultrasonic extraction of polysaccharides from Porphyra yezoensis and their inhibition effects on U937 cell growth

Polysaccharides were extracted from Porphyra yezoensis using ultrasonic extraction method and were purified the polysaccharides with DEAE-52 and Sephadex G-200 chromatogram. Through orthogonal tests,we achieved the best conditions of ultrasonic extraction process as follows: weight of Porphyra yezoensis is 15 g, volume of water is 2 L, rotation speed of pump is 12 r/s, extraction temperature is 40℃, ultrasonic power is 800W, time ratio of ultrasonic processing and intermission is 3s/2s and ultrasonic processing time is 2 h. In this method, production rate of rough polysaccharides reaches 26.29%. Then we precipitated rough polysaccharides in order with 50%, 60%, 70% and 80%(V/V) ethanol and got four ingredients of rough polysaccharides. These ingredients were purified with DEAE-52 and Sephadex G-200 chromatogram and then 5 or 3 kinds of different molecular weight polysaccharides were obtained, respectively. The former parts have a little inhibition effects on U937 cell growth, yet the latter parts have promotion effects.