Study On The Preparation Of Corncob Xylan Sulfate And Its Anti-inflammation Effects

Xylan, with a variety of biological activities, such as immune regulation, anti-tumor, anti-oxidation, etc, is a kind of hemicelluloses, which is one of the most widespread polysaccharides in nature. Especially its sulfuric acid ester attracts more and more attention for a better water solubility and broader biological activity.Beech Wood xylan sulfuric acid ester has been proved to suppress inflammation, tumor, virus, coagulations, and so on. The anti-inflammatory activity is the most widely recognized one in all of its functions, as an oral medication for Interstitial Cystitis treatment. We usually called this drug pentosan polysulfate sodium, short as PPS in research, although its registered trade mark is Elmiron. Structure of PPS is xylopyranosyls linked byβ-1,4 Glycosidic bonds to form the main chain with all hydroxyl groups replaced by sulfates. Facing with the problem of shortage of Beech Wood xylan resources, we turned to corn cobs to extract xylan which was reported to be abundant of hemicelluloses.In view of PPS structure and inflammation pathology, effect on acute and chronic inflammation of corncob xylan sulfuric acid ester was research in this study. First, we extracted corn cob xylan and prepared corncob xylan sulfuric ester with the optimum conditions, and then analyzed the structure of the sulfuric ester product. At last, we employed mouse acute and chronic inflammation model to verify anti-inflammation effect of corncob xylan sulfuric ester.The results and conclusions of this study were as follows: 1 Optimization of extraction, separation and identification of corn cob xylanOptimization of extraction method were confirmed that pretreating corncob in boiling water for 30 min, adding 15 volumes of 15% NaOH solution, keeping in 80℃water bath for 2 hours via single factor experiments. Xylan is consisted with water insoluble corncob xylan and water soluble corncob xylan, which can be obtained based on their solubility in water and ethanol. Water insoluble corncob xylan is about 2.4 times more than water soluble corncob xylan. The UV scanning showed the former polysaccharide was purer than the latter one which needs deprotein treatment with papain-sevage method. The monosaccharides of corncob xylan were determinated by TLC and GC methods. Monosaccharides of water insoluble corncob xylan were xylose and arabinose, while monosaccharides of water soluble corn cob xylan also contain glucose and galactose except xylose and arabinose.2 Preparation and activity screening of corncob xylan sulfuric acid esterComparing the performance of CISO3H/HCONH2, CISO3H/C5H5N C5H5N·SO3/C5H5N and C5H5NSO3/DMF in reaction of prepare corncob xylan sulfuric ester, which were the candidate sulfonated systems, along with thire productivities and sulfuric substituting degrees, we determined that C5H5N·SO3/DMF is the most suitable one for water insoluble corncob xylan. Three kinds of sulfuric acid ester products WISX-S1, WISX-S2, WISX-S3 with average sulfate substitute degree of 0.354,0.887 and 0.370 were prepared and applied to rat peritoneal macrophages MTT assay to determine the relationship of their anti-inflammation activity and their sulfuric substitute degree. The result showed that anti-inflammation effect was better with smaller average molecular weight and greater sulfate substitute degree.3 Structure analysis of corn cob xylan sulfuric acid esterOptimum conditions of preparing the highest activity corncob xylan sulfuric acid ester is adding 5 times of C5H5NSO3 and keeping in 70℃water bath for 6 h. We asseied some physicochemical properties of corncob xylan sulfuric acid ester, which were optical rotation value of-73.2°,sulfate substitution degree of 1.571 and molecular weight of 26.424 kDa. UV, IR and NMR in addition of GC and polarimeter were used to analyze the structures of corn cob xylan sulfuric acid ester. UV spectra showed no nucleic acid and protein; IR spectra showed that the xylose with sulfate substitution were composed ofβxylose which wereβ-linked; By analising NMR signals and comparing related elites, structure of water insoluble corn cob xylan sulfation may be determinded to a certain degree.4 Anti-inflammatory activity of corn cob xylan sulfuric acid esterWater insoluble corn cob xylan sulfate shows significant anti-inflammatory effect ether on the acute or on the chronic inflammation models, and its anti-inflammatory activity related to the administration doses. In the mouse ear edema model, administration doses of 25 mg/kg,50 mg/kg, and 100 mg/kg all have significant edema inhibition activity. The inhibition rates were (44.793±0.079)%,(51.407±0.324)% and (57.466±0.292)%. The high dosage can significantly inhibite granuloma productivity, with the inhibition rates of (37.463±9.757)%. The anti-inflammatory effect of 25 mg/kg and 50mg/kg administration dosages are both not obvious. TNF-a levels of the three dasage groups are (401.72±63.61) pg/mL,(191.79±47.67) pg/mL and (148.67±30.00) pg/mL, which are significant different comparing with the model group (838.67±93.34) pg/mL. IL-1βp contents in three groups are (58.68±31.34) pg/mL,(53.08±26.78) pg/mL and (35.48±12.40) pg/mL, from which we can see only the high dose group can significantly reduce the serum IL-1βlevel comparing with model group. NO contents of the three dose groups are (31.64±0.57)μmol/L,(30.13±0.76)μmol/L and (26.92±1.70)μmol/L, comparing with the model group (32.77±0.75)μmol/L, we know only the high dose group can significantly decrease the level of NO in serum. Inflammatory lesions was dyed through HE also suggested that corncob xylan sulfuric acid ester exhibit therapeutic effects on inflammation animal models.