ABSTRACT
ObjectiveTo establish the characteristic sugar spectrum of polysaccharides， oligosaccharides and monosaccharides of wild-simulated and transplanted Astragali Radix， and find out the difference of the sugar spectrum between the two， so as to provide a basis for quality evaluation of Astragali Radix. MethodThe relative molecular weight distribution of polysaccharides from 18 batches of wild-simulated Astragali Radix and 12 batches of transplanted Astragali Radix were characterized by high performance liquid chromatography-evaporative light scattering detection（HPLC-ELSD） to establish the characteristic chromatograms of two kinds of polysaccharides. The difference in the peak area ratio of APS-Ⅱ， a polysaccharide component with a relative molecular weight of 10 kDa， in two kinds of Astragali Radix was analyzed， and the critical value of peak area ratio of APS-Ⅱ was determined by receiver operating characteristic（ROC） curve. At the same time， APS-Ⅱ was partially acid-hydrolyzed by trifluoroacetic acid（TFA） to establish characteristic spectra of two kinds of oligosaccharides from Astragali Radix based on HPLC-ELSD， and the characteristics of differential oligosaccharides were found by principal component analysis（PCA） and orthogonal partial least squares-discriminant analysis（OPLS-DA）. Two kinds of APS-Ⅱ were completely acid-hydrolyzed by TFA and derivatized to establish characteristic spectra of two kinds of monosaccharides from Astragali Radix based on HPLC， PCA and OPLS-DA were performed on the peak area ratio of two kinds of monosaccharides to explore the differences in the composition of two kinds of APS-Ⅱ monosaccharides. ResultThe characteristic sugar spectrum of polysaccharides from Astragali Radix showed that the peak area ratio of APS-Ⅱ was the main difference， and the peak area of APS-Ⅱ of wild-simulated and transplanted Astragali Radix were 89.17%-97.17% and 80.14%-91.96%， respectively. The ROC curve determined the critical value of 92.28% for the difference of APS-Ⅱ peak area ratio of the two kinds of Astragali Radix. The multivariate analysis of APS-Ⅱ oligosaccharides revealed that the peak area ratio of oligosaccharides with polymerization degree≥10 was the main difference， which ranged from 11.835%-19.092% for wild-simulated products and 2.778%-7.017% for transplanted products. The results of monosaccharide characteristic sugar spectrum analysis showed that both Astragali Radix species consisted of six monosaccharides， and glucose and arabinose were the differential monosaccharide fractions. The peak area ratios of glucose and arabinose in wild-simulated products were 85%-93.9% and 2.7%-5.8%， respectively， while those of transplanted products were 74.3%-87.3% and 5.3%-10.7%， suggesting that the structures of the two polysaccharide fractions APS-Ⅱ of Astragali Radix may be different. ConclusionThe difference of sugar spectrum between two kinds of Astragali Radix may be related to the content and structure of APS-Ⅱ， and this study may provide a reference for the study of carbohydrates in Astragali Radix and the quality evaluation of medicinal materials.