Study On The Protective Mechanism Of Pomegranate Peel Polyphenols And Short-chain Fatty Acids On The Damage Of Colon Cell Function

In recent years,with the economic development,people's living standards have changed a lot.People's dietary structure is generally high-fat diet,and this mode will greatly increase the incidence of obesity and many chronic diseases,such as intestinal diseases,cancer,type II diabetes and so on.A long-term high-fat diet can cause intestinal flora disorder,and increase the level of endotoxin,which is mainly lipopolysaccharide(LPS),can induce chronic inflammatory reaction,and then lead to many chronic diseases.Therefore,it is very important to find the functional components of natural food to improve the negative effects of high-fat diet for the prevention of nutritional metabolic chronic diseases.Pomegranate is a kind of natural food rich in many kinds of active ingredients.Each part of pomegranate has very good edible and medicinal value.It is a natural resource worthy of development and utilization because of its wide planting and rich yield.Pomegranate Peel Polyphenol is the product of pomegranate peel extraction and purification,and its polyphenol content is high.As an underutilized part of pomegranate peel,the research on its function is of great significance.In this study,Pomegranate Peel Polyphenols extract and its metabolites,as well as Pomegranate Peel Polyphenols regulate intestinal flora to produce short chain fatty acids as experimental materials,to explore its effect on the mitochondrial function of Caco-2 colon cell model induced by LPS.First of all,Pomegranate Peel Polyphenols,Punicalagin,urolithin A,acetic acid,propionic acid and butyric acid with determined concentrations were used to pre-protect the cells.Through cell activity detection,mitochondrial membrane potential change trend detection,intracellular ROS content determination,mitochondrial permeability transition pore(MPTP)opening degree and intracellular ATP content detection,Pomegranate Peel Polyphenols,their metabolites and short chain fatty acids were explored the possible effects of their mechanisms on the mitochondrial function of Caco-2 cells treated with LPS.Secondly,the expression of IKB-?,p-ERK/ERK,C-Caspase-9/Caspase-9,the activity of Caspase-3,the contents of PARP and Cytochrome C(Cyt C)in Caco-2 cells were determined to explore the possible effects of Pomegranate Peel Polyphenols,their metabolites and short chain fatty acids on the endogenous apoptosis of Caco-2 cells induced by LPS.The main results are as follows:(1)Pomegranate Peel Polyphenols,their metabolites and short chain fatty acids could protect the mitochondrial function of Caco-2 cells after LPS treatment.Compared with the control group,LPS could decrease the mitochondrial membrane potential,increase the content of ROS,increase the opening of mitochondrial permeability transition pore and decrease the content of ATP.However,the mitochondrial membrane potential increased significantly,the ROS content decreased significantly,the opening of mitochondrial permeability transition pore decreased to a certain extent,and the ATP content increased.These results indicate that pomegranate peel extract and its metabolites,and Pomegranate Peel Polyphenols can effectively improve the mitochondrial function of colon cells.(2)The activity of Caspase-3 increased,the contents of PARP decreased,and the level of Cytochrome C increased in Caco-2 cells treated with LPS.However,the Caspase-3 activity of Caco-2 cells treated with Pomegranate Peel Polyphenols,Punicalagin,urolithin A,acetic acid,propionic acid and butyric acid were inhibited,which blocked the endogenous apoptosis pathway.These results indicate that pomegranate peel extract and its metabolites,as well as Pomegranate Peel Polyphenols regulate the short chain fatty acids produced by intestinal flora,and inhibit the endogenous apoptosis of colon cells induced by LPS.(3)Pomegranate Peel Polyphenols,their metabolites and short chain fatty acids could inhibit the increase of IKB-a protein expression induced by LPS in Caco-2 cells,regulate the activity of NF-?B,thus preventing the occurrence of Caspase cascade reaction;at the same time,they could also inhibit the excessive phosphorylation of ERK1/2 protein induced by LPS in Caco-2 cells,making the ATP level of cells at normal level,maintaining the normal growth of cells;in addition,they could also effectively inhibit the activation of Caspase-9 in Caco-2 cells induced by LPS,thus affecting its regulation of downstream Caspase-3,and hindering the process of apoptosis through endogenous pathway.This study explored the mechanism of Pomegranate Peel Polyphenols and their metabolites,short chain fatty acids on LPS induced mitochondrial function and endogenous apoptosis of colon cells,and provided a theoretical basis for Pomegranate Peel Polyphenols to improve colon epithelial cell damage and intestinal dysfunction caused by high-fat diet.