Study On The Immune Activity Of Chickpea Polypeptide

Chickpeas(Cicer aretinum L.)has high nutritional value and medicinal value.Therefore,related foods such as chickpea cakes and canned chickpeas processed with chickpeas as raw materials have the potential to become mainstream legumes.The protein content of chickpea seeds is about 30% of its dry weight,and the protein components contained in it have much higher physiological activities in enhancing immunity,anti-oxidation,anti-tumor,and lowering cholesterol than soybeans,peas and other legumes..Chickpea peptides are a mixture of small molecule peptides,which are easily digested,absorbed and utilized by the human body.They are obtained by hydrolysis of chickpea protein through specific proteases.Its amino acid composition is almost the same as that of chickpea protein.Compared with chickpea protein,the processing characteristics and physiological activity of chickpea polypeptide are superior.Studies have shown that peptides isolated from beans can effectively improve the resistance of organisms to diseases,improve the phagocytosis of macrophages,stimulate non-specific immune defense systems and protect organisms from damage.The relative molecular masses of these peptides are mainly between 50 and 1500 Da.At present,there are few reports on the preparation process and immune activity of chickpea peptides.Therefore,this article uses high-quality chickpeas purchased from Mulei County,Xinjiang as raw materials,and takes the yield of chickpea peptides as an indicator.The response surface method is used to optimize the enzymatic preparation process of chickpea peptides,and Sephadex G-15 is used.The obtained chickpea polypeptide was separated and purified.On this basis,its relative molecular mass and amino acid composition were analyzed.Finally,the immunomodulatory effects of chickpea peptides on cyclophosphamide-induced immunocompromised mouse models and aging mouse models were studied.The contents and results of this experiment are as follows:1.Chickpea protein was prepared by alkali-dissolving acid precipitation method with chickpeas as raw materials.The optimal preparation process for preparing chickpea peptides from enzymatic protein was determined by single factor analysis combined with orthogonal experiment method: the amount of enzyme added was 5300.U/g,p H 7,reaction time 220 min,reaction temperature 56 ℃,under these conditions,the peptide yield was 63.94%;After separation and purification by Sephadex G-15,a higher content of peptide component CPe II was obtained.The relative molecular mass distribution and amino acid composition analysis results of the CPeⅡ component show that its molecular mass is in the range of 118-1476 Da,and mainly concentrated below 1000 Da.Some studies have found that peptides with a relative molecular mass mainly concentrated around 1500 Da have better results.The rich amino acids include glutamic acid,aspartic acid,arginine,lysine,leucine,serine and so on.Among them,glutamic acid has the highest content,accounting for 18.412%;followed by aspartic acid and arginine,accounting for 9.592% and 7.088% respectively.The purified polypeptide has a purity of 97.1%.2.To explore the immunomodulatory effects of chickpea peptides on cyclophosphamide-induced immunocompromised mouse models,the experiment established a blank group,a model group(cyclophosphamide,40 mg/kg),and a positive control group(pidotimod,25 mg/kg)and chickpea polypeptide low(50 mg/kg),medium(100 mg/kg),and high(200 mg/kg)dose groups.After the test,the spleen and thymus index,spleen and thymus tissue morphology,splenic lymphocyte proliferation and transformation ability,serum immunoglobulin Ig G,Ig A and Ig M content,and cytokines IFN-γ,IL-6,IL were examined after the experiment was completed.-2 content to study its immunomodulatory effect.In order to further study its immune regulation mechanism and explore the immunomodulatory effects of chickpea peptides on RAW264.7 cells,a blank group,chickpea peptide test groups(50,100,200 and 400 μg/m L)and a positive control group were set up in the experiment.(Lipopolysaccharide,2 μg/m L),to study its immune regulation by investigating chickpea peptides on cell proliferation rate,cell morphology,cell phagocytosis and the secretion level of NO,TNF-α,IL-6,IL-1β effect.The results showed that: 1.Chickpea peptides can increase the spleen index and thymus index of immunocompromised mice,effectively alleviate the damage of cyclophosphamide to the mouse spleen and thymus tissue;promote the proliferation of mouse spleen lymphocytes,and improve the Con A-induced splenic lymphocyte proliferation rate;increase the secretion of IL-2,IL-6,IFN-γ and other cytokines in the serum of immunocompromised mice with a dose-effect relationship;for mice induced by cyclophosphamide Decreased serum Ig G,Ig A and Ig M levels have a significant recovery effect,and there is a dose-effect relationship.It indicates that chickpea peptides may enhance the immunity of mice through cellular and humoral immunity.2.In the mass concentration range of50～400 μg/m L,chickpea peptides can promote the proliferation of RAW264.7 cells and activate the cells;significantly increase the relative phagocytic rate of RAW264.7 cells(p<0.05),and there is a dose-effect relationship;Stimulate RAW264.7 cells to secrete NO,TNF-α,IL-6 and IL-1β,and the effect becomes more significant as the concentration increases.These indicate that chickpea polypeptides can enhance the body’s innate immune function and thus exert an immune regulation effect.3.To explore the immunomodulatory effects of chickpea peptides on aging mouse models,the experiment established a blank group,a model group(D-galactose,125 mg/kg),and a positive control group(Vitamin E,50 mg/kg)and chickpea polypeptide low(50 mg/kg),medium(100 mg/kg),and high(200 mg/kg)dose groups.After the 42-day animal experiment,the immunomodulatory effects of the mouse thymus and spleen organ index,the degree of ear swelling,the proliferation and transformation ability of splenic lymphocytes,the serum hemolysin content,and the phagocytic ability of mononuclear macrophages were investigated by investigating the index of mouse thymus and spleen organs.The results show that: chickpea polypeptide can increase the thymus and spleen index of aging mice;increase the degree of ear swelling in mice,and the swelling degree gradually increases with the increase of concentration;promote the proliferation of mouse spleen lymphocytes,and improve Con A-induced proliferation rate of splenic lymphocytes;increased serum hemolysin content of aging mice;increased phagocytic ability of monocytes and macrophages in aging mice,but there was no obvious dose-effect relationship.It shows that chickpea peptides can effectively improve the body’s specific and non-specific immune functions.From the above results,it can be seen that the chickpea polypeptide has good immune activity.This research is conducive to expanding the development and utilization of chickpea and chickpea polypeptide resources in Xinjiang,provides a theoretical basis for the study of the physiological activity of chickpea polypeptides,and has positive significance for the comprehensive utilization of chickpea resources in many aspects.