Study On Extraction Technology And Antioxidant Activity Of Crude Polysaccharide From Solidago Solidago

Solidago Canadensis has become an invasive species in recent years due to its lack of natural enemies.However,as a medicinal plant,its plant polysaccharides have a variety of biological activities.This paper aims to explore the extraction,purification,structure identification and antioxidant activity of Solidago polysaccharide.（1）Hot water extraction method and response surface analysis method wereusedto optimize the extraction temperature,extraction time and solid-liquid ratio of Solidago Canadensisto obtain solidago crude polysaccharide（SCL-C）.Meanwhile,the optimal extraction process of polysaccharides from Solidago Canadensis was obtained as follows:extraction temperature was 90℃,the extraction time was 2.5 h,liquid to solid ratio was 1:24.（2）Solidago Canadensis was decolorized and deproteinized by macroporous resin adsorption method,and its adsorption kinetics curve was studied.By testing the adsorption capacity of eight macroporous resins,the comprehensive comparison showed that the decolorization efficiency of D-101 resin was higher.Then through orthogonal test,the optimal decolorization process parameters were as follows:the concentration of sample solution was 3 g/L,p H was 4,and the flow rate of sample solution was 1.25 m L/min.Finally,the refined solidago polysaccharide（SCl-J）is obtained.（3）SCL-J was further separated and purified by DEAE-52 ion exchange chromatography and Sefacryl S-100 HR gel column chromatography to obtain four polysaccharide components,namely SCL-M,SCL-0.2M,SCL-0.5M and SCL-1.0M.The molecular weight of SCL-0.2M-B,the main component of polysaccharides,was determined by high performance gel penetration chromatography（HPGPC）.The preliminary structure of SCL-0.2M-B was analyzed by gas chromatography,infrared spectroscopy,methylation and nuclear magnetic resonance（NMR）.The results showed that SCL-0.2M-B was a homogeneous polysaccharide with an average molecular weight of35266,and it was composed of arabinose,galactose,glucose,xylose and galacturonic acid.The methylation reaction and NMR spectra showed that SCL-0.2M-B mainly contained six types of ligation types:1-Araf,1,5-Araf,1,3-Glcp,1,4-Galp,1,3-Galp and 1,4,6-Galp.The molar percentages were 6.88%,16.46%,6.28%,24.49%,3.22%and 3.03%,respectively.1,4-Galp and 1,5-Araf may form the main chain structure,and Gapl was the main sugar unit of SCL-0.2M-B.（4）The antioxidant activity of SCL-0.2M-B was also determined.The results showed that SCL-0.2M-B had good scavenging ability on O₂^-radicals,·OH hydroxyl radicals,DPPH·,H₂O₂,ABTS⁺radicals,and the scavenging activity order was ABTS⁺>DPPH>O₂^->H₂O_2.The scavenging effect of SCL-0.2M-B was related to the concentration of polysaccharide solution,which was enhanced with the increase of the concentration of polysaccharide solution,showing a certain dose-effect relationship.The maximum scavenging rates of ABTS⁺,DPPH·,O₂^-,H₂O₂ were 61.10%,58.91%,63.02%,66.12%,respectively.It is proved that Solidago polysaccharide had good antioxidant activity.