ABSTRACT
The grading and quality analysis methods for different commercial Glycyrrhiza Polygalae Radix slices were established. The qualities of different grade samples were analyzed and compared, in order to provide useful information for the formulation of the grading standards of Glycyrrhiza Polygalae Radix slices. A total of 34 batches of Glycyrrhiza Polygalae Radix slice samples collected from 12 companies were divided into two grades: first-grade (diameter ≥ 3.0 mm) and second-grade (diameter < 3.0 mm). Thin-layer chromatography (TLC), multi-component content determination and fingerprint analysis were used to analyze the qualities of different grades of Glycyrrhiza Polygalae Radix slices, and the fingerprints were statistically analyzed using partial least squares-discriminant analysis (PLS-DA) and orthogonal partial least squares-discriminant analysis (OPLS-DA). The results showed that the established TLC method can simultaneously identify three major types of components, including sugar esters, xanthones, and saponins in Glycyrrhiza Polygalae Radix slices, and has obvious advantage compared to the existing methods for its rich information, low cost, and easy or safe operation. The multi-component determination showed that the contents of three index components (polygalaxanthone Ⅲ, 3,6'-disinapoyl sucrose and tenuifolin) in the first-grade products of Glycyrrhiza Polygalae Radix slices were lower than those in the second-grade products. The results of PLS-DA and OPLS-DA indicated significant differences were observed between the first-grade and second-grade products, with sibiricose A5, sibiricose A6, polygalaxanthone Ⅲ, 3,6'-disinapoyl sucrose and tenuifoliside A being identifies as the major differentiate markers.