Study On The Structure-activity Relationship Of Primary Structure Of The Polysaccharides Produced By Lachnum Sp.

In this dissertation,the author conducted a series of study on the polysaccharide extracted from the mycelium of the Discomycetes, and their physicochemical characteristics and chemical structure were determined with instruments analysis technique and chemical modification technique of biomacromolecule,and their antioxidation activity were investigated with medical analysis technique and biological active analysis technique.The following results were achieved1. The crude water soluble polysaccharides of the Discomycetes were extracted by hot water and precipitated by adding ethanol,through isolation and purified gained pure polysaccharides IPS-I,and the pure degree of polysaccharide IPS-I is99.4%. The IPS-I is a white powdery substance, and it is soluble in water and insoluble in common organic solvents.The average molecular weight of IPS-I is146083Dal.The unit monosaccharide of IPS-I was identified as glucose, galactose, mannose with a ratio of1:1.31:2.87,the sugar chain of IPS-I is composed of1â†'3linked,1â†'4linked,1â†'6linked,and1â†'2linked in a ratio of13:65:7:15.Infrared spectrum spectrum of IPS-I results showed that monosaccharide of DFPN-I were all β-pyranose.2. IPS-I was have antioxidation active and within a certain concentration range,the activity and concentration shows positive correlation.In order to estimate the antioxidation activity of IPS-I,three systems of generating superoxide radical, hydroxyl radical,DPPH radical and Nitroso radical were designed.The results showed that IPS-I was effective in scavenging superoxide radical and hydroxyl radical, the effect of hydroxyl radical(·OH)scavenging is most obvious.3. We used chlorosulfonic acid-pyridine method to modify IPS-I.The substituent degree of vitriol esterified IPS-I was0.69. Sulfated modification can significantly enhance the scavenging activity of the polysaccharide on Nitroso (NO2),and also can slightly enhance the characteristical in the water solubility.When the polysaccharide concentration is reached3mg/mL,IPS-I and S-IPS-I have the same ability on the Nitroso scavenging.Main creative points in the dissertation are summarized as following:1. The polysaccharide extracted from the mycelium of the Discomycetes is composed of four parts,and the IPS-I content is highest winthin them.The new polysaccharides IPS-I was isolated and purified from polysaccharide.IPS-I is composed of glucose,mannose,galactose,and it is neutral water soluble polysaccharide.2. We used chlorosulfonic acid-pyridine method to modify IPS-I.Sulfated modification can significantly enhance the scavenging activity of the polysaccharide on Nitroso(NO2). When the polysaccharide concentration is reached3mg/mL,IPS-I and S-IPS-I have the same ability on the Nitroso scavenging.3. The preliminary structural characterization of the IPS-I and S-IPS-I provides a theoretical basis for the study of the relationship between structure and function,and Illustrates the relationship between activity and structure at the molecular level.