Structural Characterization And Anti-tumor Activity Of An Acidic Polysaccharide From Codonopsis Pilosula

Codonopsis pilosula is a commonly used traditional Chinese medicine, which contains polysaccharides, saponins, sesquiterpenes, polyphenols, glycosides, alkaloids, volatile oil et al. As one of the important active ingredient in Codonopsis pilosula, Codonopsis pilosula polysaccharides (CPP) caused widespread concern of pharmacy and related workers. However, research of homogeneity CPP rarely reported. Our study systematicly investigated the extraction, separation and purification process, and its anti-tumor and anti-oxidant activity of CPP. Specific studies as follows:(1) CPP was extracted, using a central composite design and response surface methodology by double indicators including the yield of crude polysaccharide and sugar content. Final optimization results as follows:extraction temperature91℃. extraction time120min.ratio of water to raw material9,number of extraction4times.(2) Determination the content of organic selenium in CPP:CPP extracted according to method of(1), precipitated1/2concentrate by80%alcohol,and another1/2by30%.50%,70%and80%respectively which named CPP1, CPP2, CPP3and CPP4after freeze-drying. Hydride generation atomic fluorescence spectrometry was used to determine the content of organic selenium in CPP1, CPP2, CPP3and CPP4and Codonopsis pilosula polysaccharide in fifferent areas. Results confirmed that the organic selenium in Codonopsis pilosula mainly distributed in polysaccharide, and the study provided a theoretical and technical support for the development of the products of Codonopsis pilosula selenium polysaccharide.(3) The scavenging effects of different fractions of Wendang polysaccharides and Codonopsis pilosula polysaccharide in fifferent areas on three free radicals (·O2-,-OH and·DPPH)were studied.The results showed that Wendang polysaccharides had a strong scavenging ability for the three free radicals.(4) Three acidic polysaccharides were isolated from CPP1,and preliminarily studied the properties by means of high performance gel permeation chromatography(HPGPC),sulfuric acid—carbazole method and elemental analysis et al.The structure of one acidic polysaccharide (CPP1b)was researched emphatically. High performance gel permeation chromatography coupled with multi-angle laser light scattering(HPGPC—MALLS)was used to determine weight-average molecular weight (Mw) and root mean square radius (RMS) of CPP1b, which were1.45×105Da,29.7nm respectively, and presented random coil in0.9%NaCl solution. Gas chromatography, methylation analysis and one-dimensional and two-dimensional nuclear magnetic resonance (NMR) technology et al.were used to determine the structure of CPPlb, and the final structure was deduced as follows:1→4linked a-D-GalpA3Ac,1→6linked a-D-Galp3Ac4NAc which was branch with a terminal a-L-Arap, and1→2linkedβ-L-Rhap. Scanning electric microscopy (SEM), transmission electron microscopy (TEM),atomic force microscope (AFM) were used to study the the ultrastructure of CPP1b under different conditions.Thiazolyl blue tetrazolium bromide(MTT) assay was used to study the inhibitition of CPPlb against human lung cancer cells A549in different concentrations, and results showed that CPPlb presents potential anti-tumor activity.