Structure Characterization and Antitumor Activity of Polysaccharide WPP2 from Pleurotus Eryngii

Abstract

Polysaccharides are an important class of active components from Pleurotus eryngii with potential biological activities.Scince structure and functions are intimately related,an in-depth study of Pleurotus eryngii polysaccharides would be of interest.In this work,crude polysaccharides were extracted from Pleurotus eryngii by hot water and were further fractionated to give a new polysaccharide fraction termed WPP2.WPP2 was subjected to structural identification by means of UV,HPLC,GC,IR,GC-MS,NMR,ESEM and AFM.In addition,the antioxidant and antitumor activities of WPP2 were evaluated in vitro.The results revealed that WPP2 is rich in Glc with an average molecular weight of about 4.499 ×105.The main chain of WPP2 was made up of →1,3)-β-D-Glcp,→1,6)-β-D-Galp,and→1,3)-β-D-Manp with two side chains.→1,6)-β-DGlcp,→1,6)-β-D-Galp and terminal residue→1)-β-D-Glcp were linked to form side chains bearing→1,2,3)-β-D-Manp and→1,2,6)-β-D-Manp residues as branched points.Congo red reaction indicated that WPP2 has the triple-helical structure in aqueous solution.The multi-branched structure of WPP2 was detected at the nanometer scale by ESEM and AFM;the bioactivity analysis in vitro indicated that WPP2 possessed certain antioxidant activity and antitumor effect.The results suggested that the novel polysaccharide WPP2 could potentially be used as a new natural medicine,but the relation of structure and functions need further study.