Extraction,Identification And Anti-Diabetic Activity Of Polysaccharide From Suillellus Luridus

Boletus,one of the four famous edible mushrooms,has the nutritional characteristics of low fat,high protein and carbohydrate,and reasonable amino acid composition.It is an edible mushroom with great commercial potential and research value.Based on the previous research on the hypoglycemic and antioxidant activities of five Boletus and their water extracts in Southwest China,this paper would further analyze the primary structure,antioxidant activity in vitro and structure-activity relationship of the polysaccharides from the caps and stipes of Boletus.Then study on the antidiabetic activity of Boletus polysaccharides with the most prominent antioxidant activity in vitro was carried out.The main results are as follows:(1)The Boletus polysaccharides were mainly composed of arabinose,xylose,mannose,glucose and galactose.Most of samples displayed a broad range of molecular weight distribution,and the molecular weight of the caps polysaccharide was significantly lower than that of the stipes polysaccharide.Fourier transform infrared spectroscopy analysis revealed that most of polysaccharides from boletus mushrooms(except Boletus edulis)contained a pyranose ring.In addition,the antioxidant activities of the polysaccharides in stipes showed a significant correlation with their monosaccharide composition,and were also related to their molecular weight and anomeric configuration.Suillellus luridus collected in Pingwu,Mianyang,Sichuan,China had excellent antioxidant activity and might be developed as a natural antioxidant.(2)Three polysaccharides were extracted from the whole fruiting body,the caps and the stipes of Suillellus luridus by the hot water-extraction and ethanol precipitation.Their preliminary structures were characterized and their antidiabetic activities were evaluated to obtain the most active component.The results showed that the main molecular weight of the whole fruiting body,the caps and the stipes of Suillellus luridus polysaccharides were 6383,8172,10,710 Da,and these polysaccharides were composed of glucose,galactose,arabinose,mannose and xylose,with the highest glucose contents(41.90%–49.09%)and the lowest xylose contents(2.06%–4.36%).In addition,it was found by in vivo evaluation of diabetic mice that these three polysaccharides had potential antidiabetic activity,and their antidiabetic activity was mainly dependent on the antioxidant activity of polysaccharides.It is worth noting that the antidiabetic parameters and pathological morphology of the liver and kidney of diabetic mice with the caps of Suillellus luridus polysaccharide(150 mg/kg·bw)were normalized,indicating that the caps of Suillellus luridus polysaccharide has more significant antidiabetic activity.