Characterization And Biological Activity Of Polysaccharides From Moringa Oleifera

Moringa oleifera,also called horseradish tree,is a kind of perennial deciduous tree.Moringa oleifera grows fast with sunshine and they can tolerate drought.It is a rich source of nutrients and contains a variety of proteins,amino acids,dietary fibers,vitamins and polysaccharides.Besides high food value,Moringa oleifera is also called the “medical box” because of its medicinal properties such as free radical scavenging,anti-inflammatory,anti-infection,anti-aging,and immunity enhancing activities.Polysaccharides from various plants are crucial macromolecules during biological activities.Studies have shown that plant polysaccharides have many functions such as anti-cancer,blood pressure and blood sugar lowering,immune stimulating et al.In recent years,polysaccharides,as an important active ingredient in Moringa oleifera,have been reported about their antioxidant activities,anti-tumor,and immunomodulatory effects.However,the functional components of polysaccharides and the molecular mechanism of bioactivity are not clear.In this paper,we mainly study the extraction,purification,characterzation and biology activities of polysaccharides from Moringa oleifera.This work would benefit for the application of polysaccharides in the antioxidant,blood sugar regulation and immune regulation and lay a foundation for further exploration of their pharmacological effects and molecular mechanism.First,the polysaccharides are extracted from roots,stems and leaves of Moringa oleifera through water extraction,and four polysaccharide components,MLP20-1,MLP100-1,MLP100-3 and MRP-1 are purified using graded-alcohol precipitation,DEAE-Sepharose Fast Flow anion exchange column chromatography and dialysis.Then,FT-IR,NMR and GC-MS are used to analyze the structure characterizations of these purified polysaccharides.The results show that the four purified polysaccharides MLP20-1,MLP100-1,MLP100-3 and MRP-1 are pure carbohydrate substances.Then the vitro antioxidant activity(scavenging ability of the hydroxyl free radicals,superoxide anion free radicals and DPPH free radicals)areevaluated and the results show that the four polysaccharide components have strong antioxidant activities with the concentration-dependent manner.MLP100-1 have the strongest antioxidant activity among them.The inhibitory activity of α-glucosidase analysis show that MLP100-3 have the strongest inhibitory activity against α-glucosidase.Further,the anti-inflammatory activities of polysaccharides are studied using the vitro inflammatoryRAW264.7 macrophages cell model which is induced by LPS.The data suggestthat when the concentration is in the range of 0-100μg/mL,MRP-1 has a significant inhibitory effect on NO production of the RAW264.7 inflammatory cells;MLP100-3 can decrease LPS-induced TNF-α and NO production by down-regulating TNF-α andiNOS mRNA expression in the concentration range of 25-200μg/mL.The inhibitory activities have no significant toxic effect on macrophages.In summary,MLP20-1,MLP100-1,MLP100-3 and MRP-1 obtained from Moringa oleiferaare typical carbohydrates,and they all have strong antioxidant activities and inhibitory activities against α-glucoside.And MLP100-3 and MRP-1 can decrease the level of NO and TNF-αsignificantly on the vitro inflammatoryRAW264.7 macrophages cell model.RT-PCR show that polysaccharides can exert inhibitory effects at the iNOS and COX-2 mRNA level.It’s suspected that this inhibition can affect the release of pro-inflammatory cytokines and inflammatory mediators,thereby exerting anti-inflammatory activity.