Preparation And Biological Activity Of Extract From Polygonatum Odoratum Mill. Druce

Polygonatum odoratum（Mill.）Druce belongs to the Polygonatum（Liliaceae）genus,and it has wide distribution and contains a wealth of bioactive substances.It has great potential for development in food,health food,and pharmaceutical research as well.The current research on polygonatum odoratum is mainly focused on the isolation extraction,functional activity of polysaccharides and their small molecule compounds.Studies on its industrial preparation of polysaccharides and glycoproteins are less frequent.In this paper,dried polygonatum rhizome was used as the raw material.The preparation process of polygonatum odoratum polysaccharide was optimized and its glycoprotein isolation and purification,structural characteristics and biological activity were investigated.The main studies are as follows.（1）The preparation process of polygonatum odoratum polysaccharide was optimized,given the raw material cost,process flow and other factors in the actual production,the preparation process was determined as follows:Hunan polygonatum odoratum rhizome was selected and crushed by wet method with the material-liquid ratio of 1:40.After crushing,the rhizome was extracted in water at 75℃for 60min（1 time）,centrifuged at 9000rpm for 15min,the supernatant was extracted,and after the supernatant was cooled,0.2%papain was added,the enzyme was digested at p H=6.0 and 40℃for 2h.Centrifuged again at 9000rpm for15min,and the supernatant was taken to obtain polygonatum odoratum polysaccharide solution.（2）The dried polygonatum odoratum rhizome was crushed,and the polygonatum odoratum lectin（PDG）was obtained by physiological saline extraction,ammonium sulfate precipitation,DEAE-52 exchange chromatography and Sephadex G-100 chromatography.The glycosuppression results showed that its hemagglutination activity was inhibited by porcine gastric mucin at a minimum inhibitory concentration of0.25 mg/m L.SDS-PAGE showed that PDG contained two protein bands of 28 k Da and 14 k Da.The results of amino acid composition showed that PDG had the highest aspartic acid content with a molar ratio of 22.27%,and more acidic amino acids than basic amino acids.The sequence of amino acids at the N-terminus of polygonatum odoratum lectin was as follows:NH₂-Asp-Asn-Ser-Leu-Thr-Ser-Pro-Asn-Ser-Leu.The hemagglutinating activity of PDG was significantly affected by temperature,and the hemagglutination activity decreases with increasing resting time under high temperature conditions.At p H=5.0～11.0,the hemagglutination activity of PDG was maintained stably at 2⁵.（3）PDG showed scavenging effects on ABTS+-,DPPH-and-OH,and the lectin was significantly more effective in scavenging ABTS+·and DPPH·than-OH radicals.PDG did not inhibit Bacillus subtilis,Enterobacter aerogenes,Staphylococcus aureus and Shewanella.PDG had no effect on the growth of macrophages when it was applied to macrophages.When PDG was co-cultured with Saccharomyces cerevisiae for 24h,300μg/m L of PDG had a catalytic effect on the growth of Saccharomyces cerevisiae.