Isolation,Purification And Structure Identification Of Polysaccharides From The Spores Of Ganoderma Lucidum

Ganoderma lucidum is a kind of precious medicinal fungi,which has a history of more than two thousand years in China.Ganoderma spores are germ cells of G.lucidum,containing polysaccharides,triterpenoids,nucleosides and other active ingredients.Studies have shown that polysaccharides of G.lucidum spores have many pharmacological effects,such as immunomodulatory,anti-tumor,antioxidant,hypoglycemic and so on.At present,most of the products of G.lucidum spores are broken cellular wall on the market.The yield of polysaccharide is improved effectively after breaking the wall,but it is not clear what differences exist between polysaccharides before and after breaking cellular wall.In this study,through the separation,purification and structural analysis of polysaccharides from unbroken G.lucidum spores and cell wall of G.lucidum spores,the differences of polysaccharides in G.lucidum spores before and after breaking cellular wall were clarified,which laid the foundation for the application of polysaccharides from G.lucidum spores.The main results of this study are as follows:(1)G.lucidum spore powder was extracted with boiling water,and the combined aqueous extracts were subjected to graded alcohol precipitation,and the same to the broken G.lucidum spore powder,which had been extracted with boiling water before breaking the wall.Through the analysis and comparison of the yield,molecular weight distribution,polysaccharide content,beta glucan content,protein content and monosaccharide composition,the following conclusions were drawn: The method of fractional ethanol precipitation could effectively separate aqueous extracts of unbroken G.lucidum spores and cell wall of G.lucidum spores.Polysaccharide and beta glucan mainly concentrated in 50% and 70% alcohol precipitation components of two kinds of aqueous extracts from G.lucidum spore powder,and polysaccharide contents were more than 50%,and polysaccharides were mainly beta glucan.However,the monosaccharide compositions of two extracts were obviously different.(2)The alcohol precipitation components of aqueous extracts from G.lucidum spores were isolated and purified by ion exchange chromatography and gel chromatography.As a result,5 homogeneous polysaccharides were isolated and purified from the aqueous extract of no broken G.lucidum spores,and 2 homogeneous polysaccharides were obtained from the cell wall extract.Through the analysis of sugar content,protein content,molecular weight and monosaccharide composition,it was found that 3 homogeneous polysaccharides were glucan,and the others were mainly heteropolysaccharide.(3)Based on the monosaccharide composition analysis,methylation analysis,IR,1D and 2D NMR spectroscopy,the chemical structures of three homogeneous polysaccharides were elucidated.Three homogeneous polysaccharides are all glucan,but the proportions of sugar residues and connections are different.The repeating units of three glucans are as follows:GLSB50A-Ⅲ-1GLSW50A-ⅠGLSW50A-Ⅱ...