Extraction, characterization, and biological activities of a polysaccharide from Poria cocos peels

A novel polysaccharide (PCPP-1A) from Poria cocos peels was prepared and its structural characterization and biological activities were investigated in vitro. The optimized extraction conditions of PCPP that obtained by response surface methodology were liquid to solid ratio 24.19 ml/g, extraction time 5.54 h, and extraction temperature 100°C, with the highest yield of 0.71%. Moreover, the crude PCPP was further separated by anion-exchange chromatography and gel permeation chromatography to obtain the purified PCPP-1A. Structural characterization showed that PCPP-1A had an average molecular weight of 45.38 kDa and was composed of mannose, glucuronic acid, glucose, galactose, and fucose in a molar ratio of 10.93:1.00:235.76:26.99:6.56. The results of NMR indicated that PCPP-1A might possess pyranoid glucose connected by α-type and β-type glycosidic bonds. Furthermore, PCPP-1A existed excellent potential on stimulating immune response of RAW264.7 cells and protecting AML-12 cells against radiation. These results indicated that PCPP-1A had underlying application value in the development of functional foods. Novelty impact statement A novel polysaccharide (PCPP-1A) from Poria cocos peels was prepared and its structural characterization and biological activities were investigated in vitro. These results indicated PCPP-1A existed an excellent effect on stimulating immune response of RAW264.7 cells and protecting AML-12 cells against radiation, which showed promising applications in the development of novel functional foods.