Protective Effect Of Corn Peptides Against Alcohol-induced Hepaocellular Injury

Since ancient times,wine as a special food has played an important role in daily life and social interaction.However,excessive drinking can not only lead to alcohol dependence,but also increase people's risk of illness,such as alcoholic fatty liver,cirrhosis,alcoholic hepatitis,digestive system diseases.In 1979,the World Health Organization?WHO?proposed that excessive drinking has constituted the most serious threat to human health and life.Improper drinking of alcohol has become the fifth leading risk factor for premature death and disability worldwide.Alcoholic liver disease?ALD?,also known as alcoholic liver injury,is a liver disease caused by chronic or excessive alcohol intake.The pathogenesis of this disease is accompanied by pathophysiological reactions such as oxidative stress,fat accumulation,inflammatory reaction and apoptosis.And ALD is associated with genetic and environmental factors,the pathogenesis of alcoholic liver injury is very complex.There has been no specific and effective treatment.In this paper,corn-derived peptides were used as experimental materials to study the protective effect of corn-derived peptides on alcoholic hepatic injury and its mechanism.From the two aspects of oxidative stress and lipid metabolism,it provides a theoretical basis for the prevention and treatment of alcoholic liver disease in corn peptides.In this paper,eight known sequences of corn peptides were synthesized as experimental materials by solid phase synthesis?YFCLT,GHKPS,QLLPF,KLNPA,QFLP,AYLQ,FLPF,LLPF?.Firstly,the antioxidant activity in vitro of eight peptide derived from corn is comprehensively evaluated with the five indexes of DPPH free radical scavenging rate,ABTS free radical scavenging rate,hydroxyl radical free radical scavenging rate,Fe2+chelating capacity,and oxygen radical absorption capacity through the in vitro chemical evaluation method.The results showed that all of the eight corn peptides had some antioxidant activity.The comprehensive evaluation of the antioxidant activity of corn pentapeptides was:YFCLT,GHKPS,KLNPA,QLLPF;the antioxidant activity of tetrapeptide was:QFLP,FLPF,LLPF,AYLQ.When the pentapeptide YFCLT was at concentration of 1000?M,the DPPH radical scavenging rate was?65.09±0.15?%,the ABTS+·radical scavenging rate was?87.46±0.10?%,and the corresponding TEAC value was?89.20±0.86??M TE/1000?M,the ability to scavenge hydroxyl radicals was?86.75±0.88?%,the ability to chelate Fe²⁺was?61.41±1.93?%,the EDTA antioxidant equivalent value was?25.55±0.76??M EE/1000?M;the oxygen radical absorption ability is also the strongest,until after 160min,the relative fluorescence intensity is close to 0.Secondly,in order to further study the cell antioxidant activity in vitro of peptide derived from corn,the cell proliferation ability is measured by MTS method and the ethanol is uses as the raw material to induce alcoholic injury model of human hepatoma cell?HepG2?so as to let the cell survival rate at about 50%.It is determined to induce the HepG2 cells for 24 h with the concentration of the optimal alcohol effect of 500 mM and the cell survival rate is?59.61±6.07?%.The antioxidant activity of the eight peptide derived from corn is evaluate with the use of HepG2 cell model and among them the pentapeptide YFCLT?Tyr-Phe-Cys-Leu-Thr?has the strongest antioxidant stress effect.At the same time,the cytotoxicity experiments show that eight corn peptide have no toxic effect.Thirdly,the pentapeptide YFCLT derived from corn can be selected through the in vitro chemistry and cell experiment results for the study of anti-oxidative stress mechanism.This paper determines the effect of peptide derived from corn on the alcoholic hepatocyte model that the pentapeptide YFCLT derived from corn can reduce the hepatocyte damage index?AST,ALT?,effectively increase the antioxidant enzyme?SOD,CAT,GSH-Px?activity and reduce the reactive oxygen species ROS level and contents of inflammatory factor TNF-?.The results showed that the pentapeptide YFCLT derived from corn could inhibit the oxidative stress of alcoholic hepatocytes.Finally,this paper deterimines the effect of peptide derived from corn on the regulation of hepatic lipid metabolism of alcoholic hepatocyte model and its effect on triglyceride content,fat accumulation,and AMPK signaling pathway.The results showed that pentapeptide YFCLT derived from corn can effectively reduce the increased accumulation of triglyceride and lipid droplets due to alcohol,and can regulate the AMPK signaling pathway so as to promote the phosphorylation of AMPK,and improve the lipid metabolism.The above results indicate that the corn peptide YFCLT has certain antioxidant activity,and it can play a protective role from the two sides of the oxidative stress and the regulation of lipid metabolism to alcoholic liver injury.