Lipid-lowering Substance Basis And Mechanism Analysis Of Vinegar-egg

Vinegar-egg,a product derived from vinegar and eggs,is a healthy beverage that has been popular in China for a long time.It has multiple functions,but few studies about the antihyperlipidemic effect of vinegar-egg were investigated and the mechanism was unclear.Therefore,main components of vinegar-egg were determined in this study,hypolipidemic activities and the mechanisms of vinegar-egg were investigated by experiments in vitro and in vivo.Then,vinegar-egg hydrolysate was prepared with in vitro gastrointestinal digestion to separate and identify new bioactive peptides.Molecular docking and dynamics were simulated to provide the potential mechanisms underlying the hypolipidemic activity of the peptides.So lipid-lowering substance basis and mechanism of vinegar-egg were analyzed.Finally,these peptides were synthesized for validation purposes.These conclusions provide theoretical basis and data reference for further development of vinegar-egg and three new peptides as functional foods or hypolipidemic agents.The results are as follows:(1)Main components of vinegar-egg and its lipid-lowering and antioxidant effects in vitro and in vivo.Vinegar-egg is rich in free amino acids and inorganic elements,expecially the content of Glu,Ala,Lys,His and Val are higher than the original eggs.It has bile acid binding(43.21%),cholesterol micelle formation inhibitory and antioxidant ability associated with the free amino acids contained.To evaluate the lipid-lowering effects of vinegar-egg,hyperlipidemic mice were induced by high-fat diet.The results reveal that vinegar-egg tends to reduce body weight,fat weight,TC and TG contents,LDL-C,LDL-C/HDL-C,MDA and ALT,AST,FAS,and increase HDL-C,SOD and GSH-PX relative to the HFD group.In addition,it can increase the excretion of fecal bile acid,reduce the accumulation of lipid droplets in EAT and the degree of steatosis in the liver so that it has a certain protective effect on the liver of mice.However,it has no significant regulatory effect on LPS activity and lipid accumulation in SAT.(2)Identification and mechanism evaluation of hypolipidemic peptides.Using hypolipidemic activities of vinegar-egg hydrolysate as indicators,the optimal conditions for the preparation of vinegar-egg were set as: soaking time of 4 days,temperature of 20°C and the volume of vinegar of 160 mL.VEH-III was analyzed and identified 825 peptides by ultrafiltration and nano-LC-MS/MS.With a probability of binding pancreatic lipase less than 0.05,five peptides(ADHPFLFFIR 、 TPPFGGFR 、SDDGYFFPMPVIR、VGFHCFPK and MYCCLPASWK)were selected and identified binding site through PeptideRanker and PepSite2.Then,three peptides(ADHPFLFFIR,TPPFGGFR and MYCCLPASWK)were illustrated and their binding interactions within the active site of receptor were determined by molecular docking and dynamics simulation.Each peptide is further analysis through additional energy splitting and hydrophobic interactions.In general,a large number of hydrophobic amino acids in these peptide sequences become a prevalent feature among hypolipidemic peptides.Hydrogen bonds,Van der Waals and electrostatic interactions play a major role in bile acid binding.(3)Peptide synthesis and activity verification.Selected peptides were synthesized and the purities were above 95%.Molecular mass were 1262.60 Da,878.10 Da and 1201.50 Da,respectively.Their sequences were novel but some of them showed active domains previously reported in other bioactive peptides through BIOPEP database.These peptides were used for the validation of hypolipidemic and anxiotant activities and determination of ACE inhibitory activity.MYCCLPASWK had the strongest hypolipidemic and anxiotant activities.But TPPFGGFR(48.07%)showed more positive ability in inhibiting ACE activity compared to ADHPFLFFIR(39.67%)and MYCCLPASWK(33.30%).