Based on the ancient method of nine-steaming and nine-sun-curing,the chemical composition changes and quality profiles in different processes of Polygoni Multiflori Radix were studied. Their contents of stilbene glycoside,anthraquinones and polysaccharides were determined by nine-steaming and nine-sun-curing with black bean juice and pharmacopoeia method. HPLC chemical fingerprints were established,and orthogonal partial least squares-discriminant analysis( OPLS-DA) was performed on different processed products using SIMCA 14. 1 software to evaluate the quality difference between samples. The results of content determination show that,with the increase of the number of processing and steaming times,the stilbene glycoside and the combined anthraquinone showed a decreasing trend,and the free anthraquinone,total anthraquinone and polysaccharide showed an upward trend in the different preparations of Polygoni Multiflori Radix and Pharmacopoeia. Six-steamed and six-sun-cured products can be used as the finishing point for the classic steaming. Fingerprint results showed that there were significant differences in chemical composition in Polygoni Multiflori Radix at different processing processes. It can be identified stilbene glycoside( peak 13),emodin( peak 21),and physcion( peak 24). By comparing the relative peak areas of the 26 chromatographic peaks in the sample after normalization( the reference is peak 7),it was found that the relative peak areas of 12 peaks in the processed products were higher than the raw products,13 peaks were reduced; according to statistical analysis of OPLS-DA,Polygoni Multiflori Radix at different processing degrees was further divided into three categories,sample S1 was class I,S2-S5 were class Ⅱ,and S6-S11 were class Ⅲ． And 8 peaks with the VIP value higher than 1. 0 were peak 13,21,4,3,11,14,5,and 24 in order. The eight chemical components were the main components to distinguish the difference between Polygoni Multiflori Radix in the process of nine-steaming and nine-sun-curing,suggesting that it was rational to use stilbene glycoside,emodin and emodin methyl ether as quality control indicators of Polygoni Multiflori Radix. The method established in this experiment conformed to the methodological verification requirements,established a method of multi-component content determination combined with fingerprint,and clarified that six-steaming and six-sun-curing was used as an improved classical processing technology,and more clearly defined the whole dynamic change of chemical composition in Polygoni Multiflori Radix by nine-steaming and ninesun-curing process. It provides a basis for the chemical quality evaluation model about different processed products of Polygoni Multiflori Radix.
Keywords: OPLS-DA; Polygoni Multiflori Radix; anthraquinones; chemical fingerprint; content determination; nine-steaming and nine-sun-curing; polysaccharides; stilbene glycoside.