Extraction And Purification Of Selenium Polysaccharide From Selenium-enriched Auricularia Auricula And Its Antioxidant Activity

Auricularia auricula(L.exHook.)is a kind of medical and edible mushroom.Polysaccharide is one of the main active compounds of Auricularia auricula,with anti-oxidation,anti-tumor and so on.Selenium is an essential element and important part of Se-contained enzymes.It has many bio-activities,such as improving of immunity,anti-tumor and so on.Edible fungus has good Se accumulation,and Se-polysaccharide is organic selenium compound.It is one of the main forms of selenium in edible fungi.It has the dual bioactivity of selenium and polysaccharide,and is more easily absorbed and used by organism.It is reported that selenium polysaccharide has a higher antioxidant,enhance immunity,anti-tumor and other biological activity when compared with ordinary polysaccharides.In this paper,the extraction and purification of polysaccharides from Auricularia auricula were studied,and antioxidant activity of selenium polysaccharide and non-selenium-rich polysaccharide was studied.The results are as follows:(1)Auricularia auricula had strong selenium-enriched ability,and the selenium-enriched treatment could improve the content of polysaccharides and protein.Meanwhile,the polysaccharides and protein contained different selenium;the selenium-enriched treatment had significantly no effect on the ash content.On the whole,30mg/kg selenium of Selenium-enriched Auricularia auricula was better.(2)The optimum extraction conditions of the water-extractable method,ultrasonic assistant extraction method and ultrasonic-microwave combined extraction method were obtained by single factor test and response surface test.Ultrasonic-microwave combined extraction method were the better,and the extraction conditions of the ultrasonic-microwave combined extraction method ultrasonic time for 26 min,microwave time for 22 min,microwave power for 350 W and ratio of liquor to material 1:58(g/mL).Under the optimum conditions,the selenium polysaccharides extraction rate was highest and it was 11.79%.(3)Selenium-enriched and non-selenium-rich Auricularia auricula polysaccharides obtained four polysaccharide components after purification,and the peak of each component peak symmetry.The third component collected after purification by DEAE-52 showed a single symmetrical peak on Sephacryl S-400 column chromatography.After the purity was identified by HPGPC,a single peak was observed.The molecular weight of Selenium polysaccharide was 427.90 KDa,and the molecular weight of the non-selenium-polysaccharide was 582.29 KDa.The results showed that the content of the polysaccharide was higher than that of the selenium Polysaccharides are composed of mannose and glucose,and their molar ratio is close.Monosaccharide of the two polysaccharides contained mannose and glucose,and their molar ratio was close to each other by Meteorological chromatographic analysis.The content of selenium and the content of uronic acid of Se-APP was higher than APP after separation and purification.(4)The antioxidant activity of selenium polysaccharides extracted was better than ordinary polysaccharides after separation and purification.