Study On Antioxidant Activity And Structure Of Ophiopogon Japonicus Polysaccharide With Chemical Modified

In this thesis, Radix Ophiopogonis as the raw materials, use the method of hot water extraction and ultrasonic extraction, extracted Radix Ophiopogonis polysaccharide WPOJ and UPOJ.Then these two polysaccharides were modified by three chemical methods, namely sulfation modification, phosphorylation and carboxymethylation modification.Then assay their antioxidant activities and compared with Vc and BHT. Their spatial structure was determined with Congo red experiment, and determined the viscosity of Ophiopogon Japonicus polysaccharide WPOJ and UPOJ.WPOJ is for alkali treatment, then the exterior morphology, spatial structure and primary structure were studied.Designed to reveal the relation between the structure and activity of polysaccharides.The main contents are as follows:(1) The modification of polysaccharides WPOJ and UPOJUsing Chlorosulfonic acid-pyridine method for both polysaccharides WPOJ and UPOJ of sulfated modification, obtained the polysaccharides S-WPOJ, S-UPOJ.phosphorylation modification obtained the polysaccharides P-WPOJ, P-UPOJ.Carboxymethylation modification obtained the polysaccharides C-WPOJ, C-UPOJ. After modification of polysaccharides, using Fourier Transform Infrared Spectrum to determined.(2) Determination of the spatial structure of the Ophiopogon Japonicus polysaccharidesThe determination of the spatial structure were mainly for these8kinds polysaccharide, WPOJ, UPOJ, S-WPOJ, S-UPOJ, P-WPOJ, P-UPOJ, C-WPOJ and C-UPOJ, adopting the congo red experiment for studied.The experiment results show that the unmodified polysaccharides WPOJ and UPOJ did not show triple helix structure, while the6kinds of modified polysaccharides were showed different degrees of triple helix structure.Among these, the sulfated modification of polysaccharide S-WPOJ and S-UPOJ compared with other two kinds of modified polysaccharide, the triple helix structure were shown more obviously.(3) Determination of the antioxidant activity in vitro of Ophiopogon Japonicus polysaccharidesThe determination of the antioxidant activity in vitro were studied on these8kinds of polysaccharides.Mainly researched the determination of total reducing power, removed the ability of hydroxyl radicals, eliminated DPPH free radicals and the ability to remove super keep anion.The experiment results show that the eight kinds of ophiopogon japonicus polysaccharide has a certain degree of antioxidant activity, have a strong ability to scavenge DPPH free radicals, which clearance rate of up to about70%.which the polysaccharides of phosphorylation have a strong antioxidant activity than the other two kinds polysaccharides.(4) Determination of the viscosity of the Ophiopogon Japonicus polysaccharidesOphiopogon Japonicus polysaccharide WPOJ and UPOJ were extracted by hot water and ultrasound.the ubbelohde viscometer was used to study the effects of the viscosity on varying concentrations of Ophiopogon Japonicus polysaccharide, different temperature and different concentrations of melal ions(Na+, K+, Ca2+).Results show that viscosity of the two kinds of Ophiopogon Japonicus polysaccharide increased with the increase of its concentration and decreased with the rise of temperature.Diverse metal ions had different effect on the viscosity of Ophiopogon Japonicus polysaccharide.in comparison, Ca2+had a certain degree increase when added with increasing its concentration, but Na+, K+had a little influence.Under the determination of the concentration and temperature, the viscosity of Ophiopogon Japonicus polysaccharide extracted by ultrasound is slightly higher than hot water extraction.However, when add the metal salts ions, the viscosity of Ophiopogon Japonicus polysaccharide extracted by ultrasound is lower than the hot water extraction.(5) Structural characterization of polysaccharides of alkali treatment Ophiopogon Japonicus polysaccharide WPOJ as the raw material, through the DEAE-cellulose52column chromatography for purification, the distilled water elution composition was treated by alkali, then through the Sephadex G-150gel column chromatography to get the polysaccharide WPOJ-D-S.The results showed that the molecular weight of WPOJ-D-S was2.678×103Da, its mainly composed of mannose and glucose, the molar ratio is1:0.67.According to the results of Functional groups, there is a configuration in the polysaccharide of WPOJ-D-S, and also there is β configuration in. The spatial structure of WPOJ-D-S was determined by congo red experiment, the results showed that WPOJ-D-S has the triple helical structure.Atomic force microscopy and scanning electron microscopy results showed that WPOJ-D-S primarily exist in aggregation, form small stick and ball, in addition, observing the triple helix structure by the atomic force microscopy, which is consistent of the results of the congo red experiment.Through the periodate oxidation and Smith degradation experiment, methylated analysis and nuclear magnetic resonance (NMR,1H,13C), results showed that the main chain is composed by α-Man(1â†'2), the side chain is β-Glc(1â†'3).