Extraction of yellow pear residue polysaccharides and effects on immune function and antioxidant activity of immunosuppressed mice.

Yellow pear residue polysaccharides were extracted via water bath alcohol precipitation, and the extraction conditions were optimized through the response surface method. The yield of polysaccharides maximized to 56.88 mg/g after extraction at 67.45 °C and material-liquid ratio of 1:34.91 for 3.66 h. The crude polysaccharide was further purified to obtain high-purity polysaccharide LPB-C, it was a kind of pyranoid polysaccharide containing a beta glycosidic bond. It consisted of mannose, glucose, rhamnose and xylose and the molar ratio was 3.3:2.3:10.6:23.2. Then the test mice were grouped, modeled and intragastrically administrated and the immune function and antioxidant capacity in immunosuppressed mice were evaluated. The results showed that the administration of yellow pear residue polysaccharides could markedly improve the immune organ index, carbon clearance ability and earlap swelling rate in immunosuppressed mice, significantly increased the secretion of TNF-α, INF-γ, IL-4 and the activities of CAT, SOD, GSH-Px, and decreased MDA levels in liver, kidney and heart. The present study indicated that yellow pear residue polysaccharides might be used as a potential natural immunomodulator and have great development values in the food and medicine fields.