Extraction,Isolation,Structure Characterization And Antioxidant Activity Of Polysaccharides Derived From Panax Quinquefolius

Panax quinquefolius and Panax ginseng belongs to the same genus but different species,which has the functions of Yin-enriching,tonifying the kidney and delaying aging.Studies have shown that Panax quinquefolius polysaccharide has biological activities such as hypoglycemic and antioxidation.At present,the research of Panax quinquefolius polysaccharides mainly focuses on the roots,and the polysaccharides of stems and leaves are abandoned,which has caused resources waste to a great extent.In this paper,roots,stems and leaves of Panax quinquefolius are used as raw materials.The polysaccharides are extracted by water extraction and alcohol precipitation,and then purified by column chromatography.The structure preliminarily characterized by NMR and mass spectrometry.The biological activity of polysaccharides from the roots,stems and leaves of Panax quinquefolius are detected by antioxidant assays in vitro.The main contents and results are as follows:The crude polysaccharides of Panax quinquefolius were prepared by water extraction and alcohol precipitation.The extraction process was optimized by response surface method.The best process conditions were as follows:the ratio of solid-liquid was 20 mL/g;the extraction time and temperature were 140 min and95℃,respectively;the extraction rate was 20.17%.The enzyme-Sevag method was used for removing protein,and resin adsorption method was used for decolorization.The deproteinization of roots,stems and leaf polysaccharides were 88.6%,84.9%and82.1%,respectively.The decolorization rates were 85.4%,78.7%and 62.3%,respectively.Furthermore,polysaccharides of Panax quinquefolius root(RPS),stem(SPS)and leaf(LPS)were purified by DEAE-cellulose anion exchange chromatography column.Neutral polysaccharides of root,stem and leaf were named as RPS1,SPS1 and LPS1.Acid polysaccharides of root were named as RPS2,RPS3,RPS4,and acid polysaccharides of stem were named as SPS2,SPS3,and acid polysaccharides of leaf were named as LPS2,LPS3.All of them were eluted by different Na Cl concentrations.The molecular weight of Panax quinquefolius polysaccharide was determined by gel permeation chromatography.The molecular weight of neutral polysaccharide was between 1.9～5.4×10~5 Da.However,the molecular weight of acid polysaccharide was different,which was between 3.5×10~3 and 4.1×10~6 Da.The monosaccharide composition results showed that the neutral polysaccharide were composed of mannose,glucose and galactose,while acid polysaccharides were composed of rhamnose,uronic acid,glucose,galactose and arabinose.Neutral polysaccharides had higher glucose content,while acid polysaccharides were dominant in galacturonic acid.Polysaccharides of Panax quinquefolius root,stem and leaf didn’t have obvious difference in monosaccharide composition.The structure of polysaccharide was further detected by infrared spectroscopy,nuclear magnetic and mass spectrometry.The result showed that RPS1,SPS1 and LPS1 were pyranose with bothαandβconfigurations,and acid polysaccharides were mainlyβ-pyranose.The neutral polysaccharides were connected byα-1→4 glycosidic bonds.The galactose and galacturonic acid in RPS2,RPS3,SPS2 and LPS2 were connected in a manner of1→4 glycosidic bond,and the galacturonic acid in RPS4,SPS3 and LPS3 were connected in a manner of 1→4 glycosidic bond,too.Antioxidant activitys of Panax quinquefolius polysaccharide samples were measured by ABTS,DPPH and hydroxyl free radical scavenging methods.The results showed that Panax quinquefolius polysaccharides had certain scavenging ability in a dose-dependent manner,but the activities were lower than ascorbic acid.The antioxidant activity of polysaccharides from Panax quinquefolius root,stem and leaf was diverse in different systems.RPS3 and RPS4 had higher scavenging rates at the concentration of 10 mg/mL,which were 80.61%and 55.05%,respectively.PCA analysis showed that there were significant distinguish between neutral and acid polysaccharides,and acid polysaccharides from different parts were also discrepant.In conclusion,the differences of polysaccharides from different parts of Panax quinquefolius were explored in this paper,which provided a basis for the comprehensive utilization of Panax quinquefolius.