Effects Of Tartary Buckwheat Bioactive Peptides On Lipid Metabolism And Its Mechanism

Tartary buckwheat active peptides has the functions of reducing liver cholesterol,inhibiting body fat accumulation,promoting excretion,relieving constipation,inhibiting tumor,delaying aging,and inhibiting absorption of harmful substances.In this paper,the structural characteristics and functional analysis of tartary buckwheat 13S globulin were studied.The structure of tartary buckwheat 13S globulin?primary,secondary,three-dimensional structure?was analyzed,and its structural composition was initially identified.Six tartary buckwheat active peptides isolated from tartary buckwheat 13S globulin acidic subunit were used as research objects,In vitro antibacterial activities,cholate adsorption and antioxidant activities of six tartary buckwheat active peptides were initially identified.The cholesterol lowering mechanism and anti-oxidation activity of the tartary buckwheat active peptides were determined by Western Blot technique.Based on the above study,the structure-activity relationship between the structure and active function of tartary buckwheat 13S globulin was analyzed.The research results are as follows:?1?The primary,secondary and three-dimensional structure of tartary buckwheat 13S globulin were analysised.The results of primary structural indicated that the open reading frames of the complete coding sequence were found to encode a 515 amino acids protein precursor,which was post-translationally cleaved into a signal peptide?22 amino acids?,an acidic subunit?298 amino acids?and a basic subunit?195 amino acids?.and the 38 kDa protein is the acidic subunit of tartary buckwheat 13S globulin.The predicted secondary structureofthefull-lengthtartarybuckwheat13Sglobulin amino acid sequence indicated that the alpha helix was 32.62%,the extended strand was16.89%,and the random coil was 50.49%.Three-dimensional?3D?protein structure of buckwheat 13S globulin demonstrated that the monomer was composed by an N-terminal acidic polypeptide and a C-terminal basic polypeptide,which were connected by a disulfide bond.and then the two monomers are polymerized into a barrel structure.?2?Taking six tartary buckwheat active peptides?SR-17,CR-8,YR-26,SR-12,LR-8,GK-10?isolated from tartary buckwheat 13S globulin acidic subunit as the research object.The zone of inhibition,minimum inhibitory concentration and bacterial growth curve were determined.The results showed that the six tartary buckwheat active peptides had different inhibitory effects on Gram-positive bacteria and Gram-negative bacteria.Among them,SR-17has inhibitory effects on Gram-positive and Gram-negative bacteria,CR-8 has inhibitory effect on Gram-negative bacteria,YR-26 has inhibitory effect on Staphylococcus aureus and Bacillus licheniformis,LR-8 has an inhibitory effect on Bacillus subtilis,SR-12 and GK-10have no obvious antibacterial effect.?3?Taking the adsorption capacity of cholate?sodium taurocholate,sodium deoxycholate,sodium cholate?as an evaluation index,The cholesterol lowering mechanism of six tartary buckwheat active peptides?SR-17,CR-8,YR-26,SR-12,LR-8,GK-10?on cell were explored by Western Blot technique.The results showed that GK-10 had the best cholesterol-lowering effect.Compared with tartary buckwheat protein,the adsorption rates of sodium taurocholate,sodium deoxycholate and sodium cholate were increased by 20.21%,302.30%and 6.85%,respectively.The TC content in the HepG₂ model was decreased by 48.41%and the TG content was decreased by 31.07%.The mechanism may be to inhibit the expression of HMGCR to reduce cholesterol synthesis,thereby inhibiting lipid aggregation.?4?Taking the in vitro antioxidant capacity(Fe²⁺reducing ability,hydroxyl radical scavenging ability and ABTS free radical scavenging ability)as the evaluation index.The effects of six tartary active peptides?SR-17,CR-8,YR-26,SR-12,LR-8,GK-10?on cellular redox status and antioxidant enzyme activity were analyzed and Western Blot was used.The results show that the six tartary buckwheat active peptides have different degrees of antioxidant activity.Among them,CR-8 has the strongest antioxidant capacity,Compared with tartary buckwheat protein,ABTS free radical scavenging ability and hydroxyl radical scavenging ability were increased by 54.54%and 47.80%respectively.Compared with the model group,the MDA content decreased by 42.09%,and the GSH/GSSG ratio increased by70.63%.The activities of SOD,CAT and GSH-Px increased by 40.66%,64.66%and 26.63%,respectively.The mechanism may be through activation of the PPAR?/HO-1 signaling pathway.