Chemical structure and biological properties of a polysaccharide isolated from Pleurotus sajor-caju

Herein, a polysaccharide obtained from Pleurotus sajor-caju was fractionated via anion-exchange column chromatography and purified using gel permeation column chromatography. The chemical characterization of the polysaccharide indicated that it contained 90.16% total carbohydrate, 0% protein, 12.7% ash and 5.2% moisture; on the other hand, the carbon, hydrogen and nitrogen contents were found to be 31.53, 4.28 and 3.01%, respectively. The polysaccharide has the molecular weight of 79 kDa; the chemical structure of the polysaccharide is →6)α-d-Glc^iv(1→6)α-d-Glcⁱⁱⁱ(1→6)β-d-Glcⁱⁱ(1→6)α-d-Glcⁱ(1→units. The polysaccharide exhibited the DPPH radical scavenging activity of 21.67-68.35% at 10-160 μg ml^-1, ABTS radical scavenging activity of 16.01-70.09% at 25-125 μg ml^-1, superoxide radical scavenging activity of 24.31-73.64% at 50-250 μg ml^-1, hydroxyl radical scavenging activity of 16.64-63.51% at 25-125 μg ml^-1 and reducing power of 0.366-1.678% at 10-120 μg ml; further evaluation of the polysaccharide revealed its anticancer activity of 18.61-63.21% at 100-500 μg ml^-1 concentration against the AGS human gastric carcinoma cell line. The active principle of the polysaccharide may be used in the food and pharmacological industry in the future.