Separation,Antioxidant Activity And Prebiotic Application Of Polysaccharides From Lycium Ruthenicum Murr.fruits From Mongolia

As the main chemical component of Lycium ruthenicum Murr.fruit,polysaccharide has the function of regulating immunity,regulating intestinal flora,anti-inflammation and anti-oxidation.Lycium ruthenicum Murr.is often used in Tibetan medicine to treat cardiac fever,gynecological diseases,urethral stones,skin diseases,gingival bleeding and other diseases.Nowadays,Chinese Lycium ruthenicum Murr.in Qinghai is widely studied,but the study of Mongolia’s fruit is rarely reported.At the same time,Lycium ruthenicum Murr.polysaccharide,as a prebiote,can promote the growth of probiotics,and it can be used as a high quality prebiote,but there are few studies on this direction.The research of this paper focus on the separation and purification of Lycium ruthenicum Murr.,the identification of the physicochemical properties and basic structure of the polysaccharides,the antioxidant activity and the probiotic effect of the polysaccharides.The main research results are described as follows:1.Crude polysaccharide CLRP was obtained from Lycium ruthenicum fruit after impurity removal,water extraction,alcohol precipitation,deproteinization and freeze-drying.LRP1,LRGP2,LRP3,LRP4 and LRP5 were separated by DEAE-52 cellulose column and purified by Sephadex G-100 gel column.Five kinds of purified polysaccharides LRGP1,LRGP2,LRGP3,LRGP4 and LRGP5 were obtained.Among them,LRGP2,LRGP3 and LRGP4 had higher yields and were used in subsequent experiments.2.LRGP2,LRGP3 and LRGP4 were homogeneous polysaccharides with single peaks and symmetrical peaks determined by HPGPC.The molecular weights of LRGP2,LRGP3and LRGP4 were 1.12×10⁷Da,1.39×10⁷Da and 1.36×10⁷Da,respectively.The composition of monosaccharide was determined by precolumn derivatization（PMP-HPLC）.The results showed that the monosaccharide composition of CLRP was Man:Rha:Glc A:Gal A:Glc:Gal:Ara=0.11:0.12:0.10:0.03:0.08:0.54:1.33;The monosaccharide composition of LRGP2 was Man:Rha:Glc A:Glc:Gal:Ara=0.25:0.47:0.61:0.97:6.86:5.46;Themonosaccharide composition of LRGP3 was Rha:Glca:Gal:Ara=0.81:1.36:5.70:4.55;LRGP4 monosaccharide composition for Man:Rha:Glc A:Gal A:Glc:Gal:Ara=0.28:0.89:0.88:0.67:0.51;The four components of CLRP,LRGP2,LRGP3 and LRGP4 showed a typical polysaccharide absorption peak at4000cm^-1-400cm^-1,and the glycosidic bond type was allα-type.3.Vc was used as positive control.The antioxidant activity of CLRP,LRGP2,LRGP3and LRGP4 was evaluated by using DPPH radical,ABTS⁺radical and hydroxyl radical scavenging as indexes.The concentration of polysaccharides increased and the scavenging ability of CLRP,LRGP2,LRGP3 and LRGP4 was gradually enhanced,indicating that the polysaccharides had good antioxidant activity in vitro.4.By dynamically monitoring the dynamic changes of total sugar,total acid content,p H and colony number during the culture process,the results showed that LBP significantly promoted the growth of Lactobacillus plantarum compared with Lactobacillus acidophilus.