Physicochemical Properties,Antioxidant Capacities And Immune Activity Of Polysaccharides From Dolichos Lablab L

Dolichos lablab L is a kind of legume plant which is rich in protein,vitamins and minerals.With the development of social economy,people's requirements for food diversity is becoming popular and popular.Various healthy products have been found in nutrition products and dairy products made by beans sontinuously which is favored by the public.In recent years,Dolichos lablab L polysaccharide(DLP),which is an active component obtained from the mature seeds of lentil.There have been Studies which revealed that DLP could protect nerve cells to reduce cell apoptosis and inhibit hypoxic brain damage.Based on the previous studies,this paper optimized the methods involved in the extraction of Polysaccharide from Dolichos lablab L,NS-DLP),investigated the basic physical and chemical properties of this polysaccharide,and the antioxidant activity and antibacterial activity of the polysaccharide was examined.Moreover,immunocompromised mice was applied to explore the immunoregulatory effect of NS-DLP,and the effects on intestinal flora were further confirmed.Briefly,the main conclusions are summarized as follows:(1)In this work,hot water extraction was employed to extracted NS-DLP,and then its physicochemical properties and apparent structure were determined by High Performance Anion Exchange Chromatography,Fourier transform infrared spectroscopy,and Scanning Electron Microscope,respectively.Furthermore,the antioxidant abilities of NS-DLP were evaluated by DPPH free radical scavenging and hydroxyl free radical scavenging activities.Meanwhile,the antimicrobial activities of NS-DLP were further investigated.The results showed that pyran ring was existed in NS-DLP which molecular weights were 2.3×105 Da.Moreover,the analysis of monosaccharide composition showed that NS-DLP was composed of glucose,rhamnose,galacturonic acid,galactose,xylose and arabinose,along with the mass ratio(%)of 23.23:6.2:5.09:2.76:2.4:0.48,and sheet structures were found in NS-DLP under the Scanning Electron Microscope.Besides,antioxidant analysis indicated that NS-DLP presented hydroxyl radical and DPPH free radical scavenging activities.Subsequently,the data of bacteriostasis test demonstrated that NS-DLP diaplayed certain inhibitory activities by inhibiting Listeria and Escherichia coli.Briefly,the diameter of bacteriostatic circle of Listeria was 11.23 mm.and the diameter of bacteriostatic circle of Escherichia coli was 10.23 mm.Taken together,NS-DLP presented certain antioxidant and bacteriostatic capacities,which could provide a theoretical foundation for extend processing and developing for the application of white lentil.(2)Immunosuppressed mice caused by Cyclophosphamide(CTX)was used to investigate the immunoregulatory activities of NS-DLP.In this work,the changes of body weight,thymus and spleen organs were recorded,and the organ index of mice was calculated.The activity of T-SOD,GSH Px,CAT and the content of MDA in spleen were measured to evaluate the immunoregulation of lentil.The number of CD3+,CD4+,CD20+cells in spleen were measured by IHC.The results showed that NS-DLP could promote the recovery of the weight of immunocompromised mice,and also alleviate the splenomegaly of mice.The antioxidant data showed that NS-DLP could improve the oxidative damage of spleen tissue in immunosuppressed mice induced by CTX,and enhance the anti-oxidative abiliies.The results of this experiment suggested that the organizational structure of spleen in the normal group was clear,and the red pulp and white pulp can be clearly distinguished.Moreover,the spleen has large congestion and swelling,fibrous tissue shows hyperplasia in the model group.There are mirror like lesions and particles out of disorder.Furthermore,the decrease of granules in the cytoplasm might be due to the damage of spleen by CTX.Accordingly,NS-DLP could improve the proliferation of spleen caused by CTX,and execute a certain protective effect on spleen.Moreover,Compared with the model group,the number of CD4+cells and CD20+cells in the polysaccharide group decreased,while the number of CD3+cells increased,but there was no significant difference.These findings indicated that the production of some helper T cells in the spleen tissue of immunocompromised mice induced by CTX might promote the differentiation and maturation of B lymphocytes,make them secrete too much substances,and enhance the weight of spleen.(3)The effect of NS-DLP on the intestine of immunosuppressed mice induced by CTX.The water content,pH value,short chain fatty acids and intestinal flora of CTX-induced immunosuppressive mice were studied.The results suggested that the water content of mice was significant high in model group compared with control group.Moreover,pH measurement showed that after NS-DLP administration,the pH content of mice was decreased,indicating that NS-DLP had a positive effect on the intestinal health of mice.Therefore,the results showed that NS-DLP could regulate the proportion of intestinal flora in CTX mice.