Isolation, Purification And Structural Investigation Of Polysaccharides From Xinjiang Brassica Rapa L

Objective:1. To isolation, purify and analyze the chemical structure of Polysaccharides from Xinjiang Brassica rapa L..2. To analyze the constituents of the volatile oil from the roots of Xinjiang Brassica rapa L.. Methods:1. The refluxing method was applied to extract polysaccharides using water as solvent. The Sevag method was used to remove the protein from polysaccharides. The compounds were isolated and purified by macroporous adsorption resin column chromatography, DEAE-cellulose column chromatography, Sephadex G-150column chromatography.2. The purity of polysaccharides was evaluated by gel filtration method and UV method. Molecular weight of polysaccharides was measured by gel filtration method. Gas chromatography was applied to analyze the monosaccharides in polysaccharides and their molar ratio.3. Partial hydrolysis with acid, periodate oxidation, Smith degradation, FT-IR and NMR were used to analyze chemical structure the polysaccharides with high content.4. The essential oil of Brassica rapa L. was extracted by steam distillation. The chemical components of the essential oil were analyzed by GC-MS and the relative content of volatile oil was determined by peak area normalization method. Results:1. three polysaccharides are exhibited from Brassica rapa L.2. The molecular weight of BP1is110662, it is composed of arabinose, mannose, glucose and galactose, and the ratio is1:2.90:16.48:1.52. The molecular weight of BP2is37844, it is composed of arabinose, mannose, glucose and galactose, and the ratio is1.24:2.03:15.24:1. The molecular weight of BP3is21330, it is composed of glucose and galactose, and the ratio is1:1.5. The molecular weight of BP4is13274, it is composed of glucose and galactose, and the ratio is1.58:1. The molecular weight of BP5is5649, it is rhamnose, arabinose, mannose, glucose and galactose, and the ratio is1:1.14:3.34:5.6:1.89. The molecular weight of BP6is3516, it is composed of glucose and galactose, and the ratio is2.62:1. The molecular weight of BP6is2410, it is rhamnose, arabinose, mannose, glucose and galactose, and the ratio is1:2.31:1.07:22.43:1.06. IR analysis shows all the7polysaccharides are composed of pyranose monosaccharides.3. The main chain of BP1is mainly made up of α-D-Man-(1→,→6)α-D-Glcp-(1→and→2,6)β-D-Galp-(1→. The side chain of BP1is mainly made up ofα-D-Man-(1→and→6)α-D-Glcp-(1→. The main chain of BP2is mainly made up of→6)α-D-Araf-(1→,→6)α-D-Man-(1→and→6)β-D-Glcp-(1→. The side chain of BP2is mainly made up of→6)β-D-Glcp-(1→.4.38peaks are separated totally,35components are identified,and which accounted for96.55%of the total content of the volatile oil.Conclusion:1. It has been proved that the7polysaccharides fractions were pure aand homogeneous, so the methods were used are feasible and workable.2. Structural elucidation shows that mostly of Brassica rapa L. polysaccharides are complicated heteropolysaccharides with multi-branch.