Chemical Modification Of Pachymaran And Its Antioxidant Activity

Polysaccharides which have been chemically modified have particular bioactivities and this has been paid much more attention to. Some chemical function groups have been attached on the chain of these polysaccharides, so their solubility, structure, physical-properties, chemical characters and bioactivities have been changed to some extent. Poria cocos sclerotium contains70-90%dry weight of polysaccharides in which the largest chemical component is D-glucose. Because the polysaccharide is not soluble in water, it is essential to make chemical modification of phachymaran to increase its water-solubility, which is also useful for studying its biological between activities and structure.In this paper, we extracted polysaccharides from Poria cocos by one factor and orthogonal experiment. The research optimization of extraction temperature, ratio of solid-liquid, and the duration of time extraction in extraction alkali-soluble polysaccharide from poria cocos, has been under taken by orthogonal experiment. The optimal technological conditions are as follows:temperature5℃, ratio of solid-liquid1:30, alkali concentration0.75mol/L and the duration of time8h. The extracting rate was83.53%.Carboxymethylpachymaran was obtained as a product of the reaction of pachymaran and monochloroacetic acid in the presence of sodium hydroxide. Under experiment condition the optimal craft was45℃reaction temperature,5h reaction time, molar ratios of NaOH to pachymaran is4.8:1, and molar ratios of monochloroacetic acid to pachymaran is2.1:1.Pachymaran was chemically modified by chlorosulfonic acid-pyridine in three solvents including dimethylsuphoxide, N,N-dimethyl formamide, and pyridine. The structures of sulfated polysaccharides was determinated by IR analyze. The results suggest that chlorosulfonic acid-pyridine in pyridine for pachymaran is comparatively feasible, the product rate and degrees of substitution (DS) from the method chlorosulfonic acid-pyridine in pyridine was108%and1.33respectively. Under the same reaction conditions, the carboxymethypachymaran have been sulfated, and the carboxymethyl-sulfated pachymaran obtained, the product rate was80%, the DS of carboxy group and sulfate group was0.95and0.85respectively.The scavenging effect of polysaccharide derivatives on hydroxyl radicals(-OH) and oxygen radicals(·O2-)were tested by salicylic acid method. The results showed that the polysaccharide derivatives prepared by pachymaran can detcting hydroxyl radicals(·OH) and oxygen radicals(·O2-) deeply.