Molecule Modification Of Polysaccharides And Anticoagulation Activity

Water-soluble natural polysaccharides and their chemically modified ramifications with much more particular bioactivities have been gained more and more attentions. Some chemical function groups have been attached on the chain of these polysaccharides, so their structure, physical properties, chemical characters and bioactivities have been changed to some extent. These changes are so important in the study of relationship between structure and activities, and in the study of polysaccharides medicine that this field has become a hot point in the medicine study increasely in recent years.The rootage powder of astragalan polysaccharides (ab. AP) used as raw material firstly boiled with alcohol, the liquor with small molecule compound have been removed, the remained solid matter boiled in water. And then the macromolecule compounds in solution have been deposited by methanol. Crude water-soluble astragalan polysaccharides (content of nitrogen is 2~3%) has been acquired at last. Four methods have been applied to remove protein from crude astragalan polysaccharides: the method of trichloroacetic acid, the method of enzyme (trypsin from bovine panaeas), the method of Sevage, and the method of combination enzyme with Sevage. The results of element analysis indicated that the method of combination enzyme and Sevage was the best one. The pure AP with nitrogen content of 0.05% has been acquired using this method. Starch has been practically hydrolyzed with vitriol and water-soluble starch with Mn= 1.0-2.0 X 104(named as PAHS) has been acquired.Four methods have been introduced to acetylate AP and PAHS: Meth1:With oil of vitriol as catalyzer ,acetic acid and acetic anhydride used as acetylated reagent reacted with water liquor of AP or PAHS at 60℃ for Ih. Meth2: acetic anhydride as acetylated reagent react with AP or PAHS water liquor in pH=9~10 controlled by adding 2.25mol/L NaOH, and reacted at room temperature for Ih. Meth3: DCC as dehydrate reagent, DMAP as catalyzer, acetic acid as acetylate reagent reacted with AP in anhydrous DMSO at 40癈 for 48h. Meth4: MSA used ascatalyzer, acetic acid and acetic anhydride used as acetylate reagent reacted with the water liquor of AP or PAHS at 75℃ for 1.5 h. Aceltyated polysaccharides which were acquired with above-mentioned four methods severally have been determined their degree of acetylation (DA) with hydroxylamine colorimetry and Alpha-D-Glucose pentaacetate used as standards. The degree of four kinds of acetylated polysaccharides are 0.15~0.25> 0.30~0,40> 0.05~0.30, 0.50~0.70 in turn. The results of Meth.l indicated that DA increased with the proportion of acetic acid and water increased. The results of Meth.3 manifested that DA decreased with temperature increasing, and increased with the dose of catalyzer increasing, but increased firstly in some time then decreased with reaction time prolonged.AP, PAHS and their acetylated polysaccharides all have been sulfated with SO3. Py. Sulfated AP with different degree of sulfatization (DS) have been obtained by controlling reaction conditions: temperature, time, the dose of sulfating reagent and so on. But under the same reaction conditions, acetylated two kinds of polysaccharides (AP and PAHS) with different DA have been sulfated, and acetylated-sulfated their derivatives with different DS have been obtained. The DS of derivatives in series deceased with their DA increased. This indicates that there is a kind of competition between acetylating and sulfating on the chain of the same polysaccharides. The MW of AP, PAHS and their derivatives have been determined by Gel Permeation Chromatography (GPC) in HPLC. The DS of AP -. PAHS and their derivatives have been determined by Ion-Pair Chromatography(IC) in HPLC . The chemical structure have been determined by IR ,1HNMR, 13HNMR . The DA of acetylated-sulfated AP has been determined by 1HNMR which Methyl red sodium salt choosed as inner standards were mixed with acetylated-sulfated AP in exact mass. The DA could be worked out by the proportion of two integral values from two ki...