Study Of The Extraction, Chemical Modification, Antioxidant Activity And Structure Of Angelica Sinensis Polysaccharide

Angelica sinensis, as a kind of traditional Chinese medicine, not only play an important role in gynecological diseases, but also has an important role in blood hematopoietic, declining blood pressure, anti-tumor, anti-oxidation. Polysaccharide is one of the important effective components of angelica sinensis, it has many biological activity and function, such as anti-oxidant, anti-aging, anti-tumor, anti-radiation, anti-viral, anti-bacterial, lowering blood sugar, anti-hyperlipidemia and immune activity, etc. In this study, using Angelica sinensis as raw material, polysaccharide from Angelica sinensis?ASP? were extracted by ultrasound assisted extraction method, single factor and orthogonal test determine the appropriate factors and levels, based on the results of single factor experiments and orthogonal tests, we used response surface methodology ?RSM? to optimize the extraction conditions. Then, four kinds of chemical modification were used on the ASP, and studied its antioxidant activity at the same time. Finally, strong antioxidant activity of chemically modified polysaccharides was separated and purified and analysed ite preliminary identification of the structure and biological activity. The main contents and results are as follows:?1? Optimized the ultrasonic extraction technology of ASP, optimal levels of four independent variables was that ratio of water to raw material of 1:40g/mL, ultrasound extraction time of 25min, ultrasound extraction power 400W and ultrasonic radiation method of 10:15s/s. Three independent variables were determined by orthogonal tests. The impact on extraction yield of three variables relationship was ratio of water to raw material>ultrasound time>ultrasound power, based on the results of single factor experiments and orthogonal tests, we used RSM to get quadratic regression equation: Y=21.64+0.62X₁+0.81X₂-0.74X₃+0.47X₁X₂-0.48X₁X₃+0.67X₂X₃-1.41X₁²-0.77X₂²-1.63X₃² The X₁ was ratio of water to raw material, X₂ was ultrasound time, X₃ was ultrasound power, Y was the extraction yield of ASP. The results showed that the method can optimize the ultrasonic extraction of ASP, and the optimum process parameters was that ratio of water to raw material of 1:43.31g/mL, ultrasound time 28.06min, ultrasound power 396.83W, and the yield of ASP was 21.89±0.21%.?2? ASP was modified with four kinds of chemically methods, namely Sulfation, Phosphorylation, Acetylation and Carboxymethylation, and named as S-ASP, P-ASP, C-ASP and Ac-ASP. Then using infrared spectrum to characterize the structure. The results showed that ASP being chemical modificated had the corresponding characteristic absorption peaks, which indicated that all chemical modification had been successfully. The antioxidant activity indicated that there was no obvious enhancement of the total reducing power and scavenging hydroxyl radical of modified polysaccharide, but scavenging superoxide anion radical, DPPH radical and inhibit Fe²⁺ induced lipid peroxidation capacity were enhanced. P-ASP was the strongest to scavenging superoxide anion radical, they all showed certain dose-effect relationship. The results showed that the modificatory ASP has certain antioxidant activity.?3? P-ASP was fractionated by DEAE-52 anion-exchange and Sephadex G-150 gel-permeation chromatography, obtaining a composition termed P-ASP0. Studying the solubility, color reaction, UV, IR, HPLC, periodate oxidation, Congo red, NMR, laser particle analyzer, AFM, SEM of P-ASP0. The result of HPLC indicated that P-ASP0 is a homogeneous polysaccharide whose average molecular weight is 1.415×10⁴Da. The result of UV indicated that there is no protein and nucleic acid of P-ASP0, and in IR detection, the absorption peaks of 1057.16cm^-1 indicated that Phosphorylation modification is successful and the absorption peaks of 866.20cm^-1,740.62cm^-1, 529.87cm^-1 indicated that P-ASP0 has ?-glucopyanosyl, a configuration, pyranose ring structure. NMR also indicated that P-ASP0 has ? configuration. The result of Congo red indicated that P-ASP0 has helical structure which combined with Congo red. AFM showed that P-ASP0 is multi-branched structure, the height of each single molecular is about 1nm. SEM showed that P-ASP0 presents the appearance of a flake, rods and granular three kinds of morphology.?4? Through studying the scavenging superoxide anion radical, hydroxyl radical, DPPH radical and inhibition ?-glycosidase and ?-amylase of P-ASPO in vitro indicated that P-ASPO has the strongest scavenging capacity of superoxide anion radical, the second one is DPPH radical, the last one is hydroxyl radical. P-ASPO had certain inhibitory activity to ?-glycosidase and ?-amylase, and the inhibition ratio of is higer than that a-amylase.