Investigation On The Bioactivity And Structure-activity Relationship Of Chickpea Peptide

After digestive enzymes hydrolyzed, protein is absorbed in the form ofoligopeptide. Some oligopeptides not only provide nutrients which human growth anddevelopment needed, but also prevent and control disease, regulate physiologicalfuncitonls. Chickpea be regarded as an important folk medicine and traditionalChinese medicine, it is full of nutriments and contains a variety of bioactivities.Hence, recent attention has focused on the bioactivity peptide from natural plantresources.Albumin derived from chickpea was hydrolyzed sequentially using Alcalase andFlavorzyme proteases for production of antioxidant peptides. To identify bioactivitypeptides, chickpea peptide was fractionated using size exclusion chromatography(G-25) methods, and each fraction were names as Fra-I, II and III. Antioxidant andfree radical-scavenging activities of purified peptides were evaluated using reducingpower assays with1,1-diphenyl-2-pycrylhydrazyl (DPPH) and TEAC as well as withhydroxyl radical-scavenging assays. The results demonstrated that CPe-III exhibitedthe highest antioxidant activity compared to the other hydrolysates.To study the antitumor and immunoenhancement activity of chickpea peptide.The KM mice were randomized divided to normal control group, positive controlgroup (PC), tumor control group and three doses of chickpea peptide groups. Thebody weight, tumor growth, tumor inhibition rate, thymus index, spleen index, cellmediated immune function including lymphocyte proliferation, phagocytosis ofperitoneal macrophage and splenic lymphocyte were detected, as well as theantioxidant index in vivo: MDA, SOD and NO. Through the experiment, we foundthat a tendency of inhibition of tumor growth was observed in the chickpea group.Compared to the tumor control group, a significant increase in relative spleen weight,DTH ability，phagocytotic activity peritoneal macrophage and splenic lymphocyte inthe chickpea groups were also observed. But there is no dose-dependent effect. Theresults indicating that the peptide extracted from chickpea had anti-tumor activity,which was probably mediated by immunomodulation actions. CPe also significantlyincreased the SOD activity and reduce the content of MDA, revealing that CPe could enhance the oxidation resistance in vivo.In this research, the conformation of CPe was also systematically studied, usingthe latest modern technology including liquid chromatography-masss pectrometry(LC-MS), FT-Raman spectroscopy, infrared spectroscopy(FTIR) and molecularsimulation. CPe-III was identified to be RQSHFANAQP (1155Da) byLC-ESI-MS/MS and with the combination of BioWorks3.3; The secondary structureof CPe was tested and verified using FT-Raman Spectra and FTIR, it may containsα-helix (66%) and random coil (21%); Finally, the spatial structure of CPe wasstimulated by molecular simulation technology.This study in-depth investigated the bioactivity and conformation of CPe. Theseresults not only provide a scientific and theoretical basis for natural peptide inbiomedical application, but also give new ideas to the source of development andapplication of plant peptide.