Isolation,Purification,Antioxidant Bioactivity,Stimulated Digestion And Fermentation Of Polysaccharides From Lycium Ruthenicum Murr

Black wolfberry(Lycium ruthenicum Murr),a round and atropurpureus fruit,which planted in the northwest of china,belongs to the genus Lycium L.in the family of Solanaceae.The fruits are rich in carbohydrate,anthocyanin,mineral and vitamin,and possess certain health care function.Gut bacteria are related to human immunity,diabetes,obesity and chronic diseases,so it's important to study the effects of polysaccharides digestion and fermemtation through human body.But the research is limited.So far,the researches about the polysaccharides of black wolfberry are most about the isolation,structure and some bioactivity,and no report about the digestion and fermentation.So this article studys the isolation,antioxidation,stimulated digestion and fermentation of the polysaccharides of black wolfberry.1.Extraction of polysaccharidesUse the ethanol to pretreat the black wolfberry to get rid of pigment,grease and small molecules.Then choose hot water to extract the polysaccharides of black wolfberry.Extraction time,temperature,ratio of water to material and extraction cycles are related to the extraction efficiency.Through the single-factor tests,choose three of the extraction parameters to take a three-level,three-variable Box-Behnken design experiment,and get the optimum extraction parameters by Design Expert version 9.0.6,the results are:extraction temperature 93 ?,extraction time 4.5 h,ratio of water to material 30 mL/mg,the extraction ratio of polysaccharides is 9.16±0.15%.2.Purification and physicochemical characterization of polysaccharidesDEAE-fast flow cellulose chromatography column are used to separate crude LRP,and we got four purified polysaccharides:LRP-0,LRP-0.05,LRP-0.1,LRP-0.3.The carbonhydrate contention,protein contention,uronic acid contention and sulfuric radical contention of LRP are tested.The result of Crude LRP,LRP-0,LRP-0.05,LRP-0.1,LRP-0.3 are:carbonhydrate contention 36.60%,25.22%,29.95%,36.90%and 32.15%,protein contention 4.38%,2.47%,3.41%,2.86%,0%,uronic acid contention 56.58%,25.25%,7.69%,22.49%,63.36%,sulfuric radical contention 0.10%,0.11%,0.16%,0.09%,0.11%.Through HPLC,the molecule weight of LRP-0,LRP-0.05,LRP-0.1,LRP-0.3 are 1304.4 KDa,1435.9 KDa,1256.9 KDa and 922.7 KDa.The monosaccharide composition of Crude LRP,LRP-0,LRP-0.05,LRP-0.1,LRP-0.3 are(Man:Rha:GlcA:GalA:Glc:Gal:Xyl:Ara=0.20:0.30:0.25:0.46:0.30:0.50:0.32:0.79),(Man:Rha:GalA:Glc:Gal:Xyl:Ara=0.24:0.45:0.49:0.32:0.41:0.34:1.00),(Man:Rha:GlcA:GalA:Glc:Gal:Xyl:Ara=0.26:0.44:0.25:0.34:0.50:0.99:0.41:1.70),(Man:Rha:GlcA:GalA:Glc:Gal:Xyl:Ara=0.20:0.27:0.26:0.71:0.27:0.84:0.30:0.88),(Rha:GlcA:GalA:Gal:Ara= 0.41:0.25:0.90:0.43:0.59).3.Antioxidant activity of polysaccharidesThere are several chemical methods to measure the antioxidant activity of LRP,including reducing power,scavenging DPPH radical,superoxide radical and ABTS radical,superoxide radical.The H2O2 injured PC 12 cell module is also a good way to show the antioxidant activity of LRP in cells.Although different measures having different results due to the different principle,the crude LRP shows better antioxidant activity than purified polysaccharides.4.In vitro digestion and fermentation of crude LRP.This chapter stimulated the digestion through mouth,stomach and intestine in vitro.The results showed that the crude LRP is not digested in the mouth and intestine,but low degraded in the stomach for 6 hours.This experiment also stimulated the vitro fermentation,it turned out that the crude LRP can be degraded and utilized by microbes in this environment,producing SCFA and decreasing pH,also have influence to the intestinal flora.