| Ganoderma applanatum is a rare medicinal fungus,rich in active substances such as polysaccharide,protein and mineral elements.Among them,G.applanatum polysaccharides(GAP)are its main component,which has biological activities such as regulating immunity and anti-tumor.At present,acetylated G.applanatum(A-GAP)has not been reported.However,type 2 diabetic mellitus is a chronic disease with multiple complications.Its therapeutic drugs are mostly aimed at lowering blood glucose,and include multiple side effects.This topic was about the effect of A-GAP on type 2 diabetes mice.In this work,A-GAP was extracted from G.applanatum polysaccharides by acetylated modification.The structure characteristics of A-GAP were analyzed by HPLC,IR,NMR and GPC,the antioxidant activity in vitro was detected.The model of type 2 diabetes mellitus mice was constructed.The effects of A-GAP on the injury of type 2 diabetes mellitus mice were analyzed by combining biochemical indexes,antioxidase activity,liver and colon pathological sections,LPS and IRS concentrations of mice liver.The main results were as follows:(1)The GAP yield of water extraction alcohol precipitation method was 0.40%.The acetylation was carried out under the conditions of 10%acetic anhydride,50℃reaction temperature and 4h reaction time.The substitution degree was 0.365 by hydroxylamine colorimetry.(2)The results of HPLC and NMR showed that A-GAP was composed of mannose,ribose,rhamnose,glucuronic acid,galacturonic acid,N-Acetyl-glucosamine,glucose,galactose,xylose,arabinose and fucose with a mole ratio of 33.56:2.79:0.46:1.94:0.26:0.37:31.79:20.97:0.71:0.98:6.20.The molecular weight of A-GAP was 1.22×10~4Da by GPC.The results of IR showed that A-GAP had a special absorption peak of polysaccharide with pyranose and was successfully modified by acetylation.(3)The in vitro antioxidant results showed that the scavenging activities of A-GAP on DPPH and hydroxyl radicals were 75.35±0.16%and 45.16±0.06%,26.36%and 44.04%higher than that of GAP,respectively.The reducing power of A-GAP was 0.31±0.01,32.26%higher than that of GAP,indicating that A-GAP had strong antioxidant activity.(4)A-GAP could alleviate the injury of type 2 diabetic mice.The principal findings were as follows:(1)A-GAP could reduce fasting blood glucose and liver index in type 2 diabetic mice.(2)A-GAP can improve the content of triacyllycerols(TG),low density lipoprotein cholesterol(LDL-C),high density lipoprotein cholesterol(HDL-C),and lower the blood lipid of the body;A-GAP can reduce concentrations of alanine transaminase(ALT)and aspartate transaminase(AST),improving the liver function and alleviate liver injury.A-GAP can reduce creatinine(CERA)concentration,and repair kidney function and increase glomerular filtration.(3)A-GAP can improve the level of superoxide dismutase(SOD),catalase(CAT),glutathione peroxidase(GSH-P_X),malondialdehyde(MDA),and enhance the resistance of the body to free radicals and lipid peroxidation.(4)The liver pathological sections were observed that A-GAP had the effect of repairing liver injury.(5)The pathological sections of colon were observed,finding that A-GAP could increase the length and density of villi,alleviate inflammatory cell infiltration and repair intestinal barrier.(6)A-GAP can reduce the concentration of lipopolysaccharide(LPS)of colon tissue,reduce harmful gram negative bacteria and restore intestinal environment;(7)A-GAP can increase the concentration of insulin receptor substrate(IRS1,IRS2),rise the effect of insulin,and improve insulin resistance.In conclusion,A-GAP had the antioxidant and alleviative effect on the injury of type 2diabetic mellitus mice,providing some reference for the screening of natural drugs for adjuvant treatment of diabetes and increasing body antioxidant. |
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