Physicochemical Properties And Antioxidant Activities Of Apple Pomace Polysaccharide And Its Mechanism In Preventing Ulcerative Colorectal Cancer

Epidemiological studies have shown that the higher the dietary fiber intake,the lower the incidence of colorectal cancer,and the close relationship between intestinal microbes and colorectal cancer.Apple pomace is an industrial by-product of the apple juice industry.There are two different apple juice production processes.One is treated with pectinase and the other is not treated with pectinase.Previously,Our laboratory conducted a series of studies on pectinase-treated apple pomace.To explore the effects of different industrial treatments on the activity of apple pomace polysaccharides and excavate the resource utilization value of apple pomace.In this study,we use apple pomace treated without pectinase as raw material,extracted apple pomace polysaccharide by subcritical water,and studied its physicochemical properties and antioxidant activity in vitro.Then AOM combined with DSS was used to construct a mouse model of ulcerative colorectal cancer,and different concentrations of NTAPP were used for dietary treatment during this period.After that,the biological activity of anti-cancer was evaluated.We measured the activity of antioxidant enzymes in serum and colorectal tissues and the level of SCFAs in cecum.To study the function and species composition of intestinal microorganisms,mouse feces in control group,AOM/DSS group and AOM/DSS + 500 mg/kg group were used for macrogenomic studies.The specific results are as follows:(1)The molecular weight of NTAPP is 170.1 KD,which is greater than that of pectinase-treated apple slag,and the content of galacturonic acid is 34.35 %,which belongs to pectin-like polysaccharides.NTAPP is mainly composed of galacturonic acid,arabinose,galactose and glucose,and does not contain fucose,mannose and glucuronic acid.The antioxidant capacity of NTAPP is not very strong overall,and it is lower than the polysaccharide extracted from pectinase-treated apple pomace.(2)NTAPP dietary treatment can alleviate the symptoms of weight loss caused by cancer and reduce the DAI value of mice.500 mg/kg NTAPP increased the thymus index of cancer mice and had no significant effect on spleen index.NTAPP dietary treatment can alleviate the symptoms of shortening of colorectal and thickening of intestinal wall caused by ulcerative colorectal cancer,significantly reduce the number of tumors,improve intestinal structure and pathological damage,and NTAPP can induce apoptosis of intestinal epithelial cells.NTAPP has a certain preventive effect on the occurrence of ulcerative colorectal cancer,and has a certain degree of dose dependence.(3)NTAPP dietary treatment can increase the activity of CAT and T-SOD in serum of mice with ulcerative colorectal cancer,significantly reduce the MDA content in colorectal tissue of mice,and prevent lipid peroxidation in colorectal tissues.At the same time,the 500 mg/kg NTAPP diet can significantly reduce the MPO content in the colorectal tissue of mice and reduce the inflammation level of colorectal tissue,indicating that NTAPP can reduce the level of free radicals in the body and reduce the level of free radicals in the tissues.Inflammation is used to prevent the occurrence of colorectal cancer.The level of short-chain fatty acids in the cecum of mice with ulcerative colorectal cancer was significantly reduced,while the dietary treatment of NTAPP increased the level of SCFAs in the cecum of mice with ulcerative colorectal cancer.(4)The acquisition of metagenomic data further reveals that NTAPP plays a role in preventing ulcerative colorectal cancer by affecting the function of intestinal microorganisms.NTAPP dietary treatment can cause significant changes in nitrogen metabolism,fatty acid biosynthesis,and cancer pathway signaling pathways;significantly increase the expression of NOG function with unknown replication,recombination and repair and function;significantly increase GH57,GH106,GH108,GH84,GT81,GH110,Abundance of CBM56,CBM62,GT14,CBM77,AA4,AA7,GH102,CBM79,PL21,GH58,CBM72,CBM58,AA5,CBM78,CBM75.(5)NTAPP dietary treatment will reduce the diversity and abundance of intestinal flora;at the same time,NTAPP diet will significantly change the abundance of its dominant intestinal flora,which will reduce the abundance of thick-walled bacteria,Abundance increases,increasing the abundance of Muribaculum intestinale and Bacteroides caecimuris,reducing the abundance of Lachnoclostridium sp.YL32 and Flavonifractor plautii.At the taxonomic level,Staphylococcus felis,Acinetobacter baumannii,and Campylobacter pinnipediorum increased significantly in the CRC group.The NTAPP dietary treatment significantly increased the Bacteroides ovatus and Bacteroides dorei,Prevotella denticola,Prevotella melaninogenica,and other species such as Flavofrractor plautii and Faecalibacterium prausnitzii.The degree will drop significantly.In summary,the apple pomace polysaccharide belongs to the pectin polysaccharide and has certain antioxidant activity in vitro.It has a certain preventive effect on the occurrence of ulcerative colorectal cancer,which can induce apoptosis and increase resistance.Oxidase activity,lowering the level of colorectal inflammation,increasing the level of SCFAs and mediating the abundance and function of intestinal microbes to function.The related research results provide a reference for the biological activity research and high value utilization of apple pomace.