A comprehensive strategy using chromatographic profiles combined with chemometric methods: Application to quality control of Polygonum cuspidatum Sieb. et Zucc

- A comprehensive strategy was established for quality control of herbs.
- The comparison between three chemometric methods was studied for the first time.
- Fifteen markers were selected for quality control according to chemometric results.
- Variances resulted from different calculation theories of the chemometric methods.
- An easily calculated parameter was adopted to reflect quality fluctuations.

For the strict quality control of herbs, a comprehensive strategy based on chromatographic profiles and chemometric methods which could reliably select quantitative indices, robustly quantitate multi-markers and systematically compare different chemometric methods was proposed and successfully applied to the quality analysis of P. cuspidatum. Based on the construction of chromatographic profiles by an efficient accelerated solvent extraction (ASE) and reliable high-performance liquid chromatography-ultraviolet (HPLC-UV) methods, different chemometric methods were employed, namely similarity analyses (SA), hierarchical clustering analysis (HCA) and linear discriminant analysis (LDA). The differences in classification of herb samples were studied for the first time. To reasonably determine the quality of herbs and evaluate different chemometric methods, a comprehensive strategy containing three key steps was performed including selection of quantitative indices, development of a reliable quantification method and adoption of an easily calculated and visible parameter. The quantitative method which was acceptable with good linearity with correlation coefficients >0.9995 and satisfactory repeatability (RSD < 1.5%), precision (RSD < 2.84%), reproducibility (RSD < 2.88%), stability (RSD < 2.85%) and recoveries (91.5%-105.6%, RSD < 2.83%) was applied to quality evaluation of fourteen batches of the P. cuspidatum samples through simultaneous quantitative determination of fifteen marker compounds. The limits of quantitation of fifteen compounds ranged from 1 to 60 μg/ml. From the results of the quality evaluation, it was found that the different calculation theories of the chemometric methods resulted in the variation of classifiers of samples: SA classified samples through the mean values and HCA & LDA classified similar objects.