Extraction,Purification,Structure Characterization And Immunomodulatory Activity Of Polysaccharides From Edible Lily

Numerous studies have shown that natural polysaccharides can maintain the health of the host by regulating the intestinal microbiota and immunity.In this study,lily bulbs were used as raw materials.The extraction process was optimized by response surface analysis,and the optimal extraction conditions were obtained.The physicochemical properties and structural characterization of pure lily polysaccharides were explored.Finally,the effect of pure lily polysaccharides on the immune function and intestinal flora of immunosuppressed mice was explored.The main results are as follows:(i)The optimal extraction process conditions of crude lily polysaccharides: liquid to material ratio20.5:1 m L/g,ultrasound time 33 min,ultrasonic power 227 W,water bath temperature 62.5℃,under these conditions,the extraction rate of crude lily polysaccharide is 16.32＋0.11%.(ii)The enzyme + Sevage method was used to remove protein.The protein-removed lily polysaccharide was further separated and purified by cellulose chromatography column and Sephadex chromatography column.Finally,the pure polysaccharide was obtained,and the total sugar content was determined to be 97.50＋0.89%.(iii)Lily polysaccharide is a homogeneous polysaccharide free of soluble reducing sugars,starch,phenolic substances and proteins.X-ray diffraction,ultraviolet spectroscopy Scanning and gel permeation chromatography test results showed that lily polysaccharide is a semi-crystalline substance with the weight average molecular weight of 25812 Da,and it didn’t contain nucleic acid and protein;Fourier infrared spectroscopy and high performance liquid chromatography analysis results showed that lily polysaccharide conforms to the typical structure of polysaccharides,and the monosaccharide composition was mainly mannose and glucose in a molar ratio of about 1.53:1.(iv)Lily polysaccharide restored the weight change and organ index of mice;improved liver and spleen damage effectively;increased serum Ig A and Ig G content;reduced TNF-α and IL-6 content in mouse colon and increase IL-10 content;reduced the content of AST,ALT and MDA in the liver of mice,increased the content of SOD;increased the relative expression of IFN-γ,IL-1β and IL-6 genes in the spleen of mice;increased the number of beneficial bacteria and reduced harmful bacteria.Improved the structure of intestinal flora and the immune function of immunosuppressed mice.Based on the above results,this study may provide experimental basis and theoretical support for lily polysaccharide to become a new type of immunomodulator in the field of functional food and drugs.