A Study On Protective Effects Of Polysaccharide From Hericium Erinaceus And Its Phosphorylated Derivatives Against Injured GES-1 Cells

Hericium erinaceus also known as Hericium erincaceus（Bull.）Pers,is a edible and medicinal fungus that has been widely used both in traditional cuisine and traditional Chinese medicine since historical records.Among them,Hericium erinaceus polysaccharide is generally regarded as a main active ingredient of Hericium erinaceus,which has various effects such as anti-inflammatory,anti-oxidation,anti-tumor and anti-liver damage in vivo.However,up to now,there are relatively few reports on the protective effects of Hericium erinaceus polysaccharide and its modified products on gastric injury based on the in vitro cell model.In the present work,the crude polysaccharide（HEP_C）,purified polysaccharide(HEP_W1,HEP_N)and phosphorylated derivatives of purified polysaccharide（P-HEP_N）from the fruiting bodies of Hericium erinaceus were prepared respectively.Structural characterization and physicochemical characteristics of the active fractions involved in the study were carried out,meanwhile,protective effects and its underlying pathways of the active substances on injured GES-1 cells were explored by methods of cell biology.The main research results are listed as follows:（1）The weight-average molecular weight（Mw）of HEP_C was detected 14.762 k Da.Thermal gravimetric analysis showed that HEP_Chad good thermal stability with the inflection point of its thermal decomposition temperature at 256.39℃.Cell modeling and cell viability assay experiments showed that HEP_C had protective effects on the H₂O₂ and CH₃COOH-induced damage of GES-1 cells,but almost no protective effect on C₂H₅OH-induced damage of GES-1 cells.（2）The weight-average molecular weight（Mw）of the purified polysaccharides HEP_W1and HEP_N fractions were detected 5.163 k Da and 12.713 k Da,respectively.Both HEP_W1 and HEP_N were found to containα-type glycosidic bonds and amorphous structure.Monosaccharide composition analysis showed that HEP_W1 was mainly composed of fucose（6.13%）,glucose（72.28%）and galactose（21.59%）;while HEP_N was mainly composed of mannose（5.13%）,glucose（43.02%）and galactose（51.85%）.Both the aqua-solutions of HEP_W1 and HEP_Nexhibited pseudoplastic fluid behavior,and neither of them can form monodisperse system.（3）HEP_W1 could repair H₂O₂-induced oxidative damage of GES-1 cells via restoring cell vitality,regulating cell cycle,inhibiting apoptosis,enhancing the antioxidant capacities of intracellular substances in injured cells and enhancing the regulating abilities of intracellular antioxidase system in injured cells etc.HEP_N could prevent H₂O₂-induced oxidative damage of GES-1 cells by restoring cell viability,inhibiting cell necrosis,reducing ROS production,and alleviating H₂O₂-induced mitochondrial dysfunction in GES-1 cells etc.（4）The yield and phosphate content of phosphorylated derivatives of purified polysaccharide（P-HEP_N）were 19.3%and 7.95%,respectively.The results of SEM and NMR analysis revealed that P-HEP_N were phosphorylated derivatives with a low degree of substitution.The dissolution performance test results showed that the solubility of P-HEP_N was better than HEP_N in heating environment,the in vitro antioxidant performance test results showed that the addition of phosphate groups contributes to improvement of P-HEP_N’s antioxidant capacity and in vitro acid-resistance test results show that P-HEP_N can tolerate the interference of low concentrations of organic acids.（5）P-HEP_N could repair CH₃COOH-induced acute injury of GES-1 cells via restoring cell vitality,promoting cell proliferation,inhibiting cell necrosis,maintaining the basic secretory function of injured cells and alleviating mitochondrial dysfunction of injured cells etc.