The Bioactivity And Degradation Of Polysaccharide From Polygonatum Sibiricum

In this paper,the extraction,separation and physicochemical properties of Polygonatum sibiricum polysaccharides,the degradation of polysaccharides and bioactivities of polysaccharides were investigated.The main conclusions were as follows:1.Preparation of polysaccharides and chemical component analysisCrude polysaccharides isolated from Polygonatum sibiricum(PSP)with hot water extraction and ethanol precipitation.Four fractions P-1,P-2,P-3,P-4 were obtained by DEAE-52 cellulose.The total sugar contents of the four fractions(P-1,P-2,P-3,P-4)were determined with phenol-sulfuric acid method.The four carbohydrate contents(P-1:70.20%,P-2:1.58%,P-3:1.14%,P-4:1.64%)were separated by DEAE-52 cellulose anion-exchange chromatography.Carbazole-sulfuric acid method was used to determine the uronic acid contents of the four fractions.The uronic acid contents were as following,P-1:0.00%,P-2:5.00%,P-3:9.21%,P-4:29.32%.HPGPC was used to determine the molecular weights of the four fractions,the main molecular weight of P-1:4.99×10~5Da,the main molecular P-2:8.62×10~4 Da,the main molecular of P-3:1.04×10~5 Da,the main molecular of P-4:1.04×10~5 Da.2.The bioactivity of polysaccharide from Polygonatum sibiricumDPPH radical scavenging activity,reducing power and ABTS radical scavenging activity were used to investigate the antioxidant activity of the four fractions.The results indicated antioxidant order:P-4>P-3>P-2>PSP>P-1.P-1 possessed the lowest antioxidant activity and P-4possessed the strongest antioxidant activity among these fractions.The inhibition ratio of all fractions on HepG2 cells were not significant.All of the P-1,P-2,P-3 and P-4 had no direct cytotoxicity against HepG2 cells.3.Degration and characterization of P-1The degradation of P-1 was investigated by microwave radiation method and acid degradation.The main molecular weight of P-1degraded by acid decreased from 4.99×10~5 Da to 1.37×10~3 Da,and the main molecular weight of P-1 degraded by microwave at the condition(240.00 W,7.00 min)decreased from 4.99×10~5 Da to 2.33×10~3 Da.The antioxidant activities of degraded P-1 were greatly improved compared to the primary P-1,especially,the degraded P-1 by microwave showed nearly 8 times antioxidant activities than the control P-1.The degradation of P-1 did not contribute the improvement of antitumor activity in vitro.Microwave is a promising technology for degradation of polysaccharide.