Isolation,Purification,Preliminary Characterization,Sulfated Modification And Activities Of Polysaccharide From Millettia Dielsiana

Millettia dielsiana is a leguminous bean plant and an evergreen wood vine.Millettia dielsiana is a traditional Chinese medicine in our country and it has the functions of blood circulation,immunity enhancement and hematopoiesis.At present,there are few studies on polysaccharides of Millettia dielsiana.In this paper,polysaccharides from Millettia dielsiana were extracted by hot-water and then purified by DEAE-52 cellulose ion-exchange column chromatography.The results showed that the yield of crude polysaccharide from Millettia dielsiana was 3.5%.A novel polysaccharide with higher purity was obtained from the crude polysaccharide and named MDP1.The sulfated modification of the polysaccharide was then carried out using the chlorosulfonic acid-pyridine method to obtain a sulfated polysaccharide and named S-MDP1.The preliminary physicochemical properties of polysaccharides were analyzed and characterized.The results indicated that the molecular weight of MDP1 was 139.54 kDa and it did not exhibit a triple helical conformation.MDP1 was a heteropolysaccharide and mainly composed of rhamnose,arabinose,galactose,and galacturonic acid.In addition,the results of UV analysis showed that MDP1 also contained trace amounts of protein,which is consistent with the results of the protein content measured by the BCA method.The thermal properties analysis of polysaccharides showed that MDP1 and S-MDP1 have better thermal stability at a certain temperature.For the sulfated polysaccharide S-MDP1,the degree of substitution was 1.94 as measured by barium chloride turbidimetric method.The results of scavenging hydroxy radical(·OH)activity of the two polysaccharides showed that the two polysaccharides exhibited a certain scavenging capacity for ·OH in vitro.In addition,the two polysaccharides also have a significant protective effect on H2O2-induced PC 12 cell injury.Immune experiments showed that both polysaccharides could promote the proliferation and phagocytosis of macrophages,and also promote the proliferation of mouse spleen lymphocytes in vitro.The proliferation rate of spleen lymphocytes was positively correlated with the concentration of polysaccharides.In vitro anticoagulant activity showed that S-MDP1 could significantly prolong APTT and TT,whereas MDP1 prolonged APTT and TT weakly,and both had no effect on PT.These results implied that MDP1 and S-MDP1 had the potential to be used as antioxidant,immunomodulatory and anticoagulant agents.