Identification of Gentiana rigescens from different geographical origins based on HPLC and FTIR fingerprints

Abstract

Gentiana rigescens is a traditional Chinese medicine with efficacy in liver protection, as a cholagogic, anti-hyperglycemic, and anti-hypertension agent, and in relieving spasms and pain. The geographical environments of different locations are very complicated, with different soils, climates, sun exposure, etc.; this has a remarkable effect on the quality of medicinal herbs. To identify different geographic origins of G. rigescens, we analyzed the high-performance liquid chromatography (HPLC) and Fourier transform infrared spectroscopy (FTIR) fingerprints of G. rigescens with the aid of chemometrics. Five variable selection methods, including competitive adaptive reweighted sampling (CARS), random frog (RF), subwindow permutation analysis (SPA), Monte Carlo uninformative variable elimination (MC-UVE) and genetic algorithms (GA), were used to screen the characteristic variables for both the HPLC and FTIR fingerprints. Then, the corresponding partial least squares discriminant analysis (PLS-DA) models were built. The results showed that for both HPLC and FTIR, the GA-PLS-DA models were the most robust models for identification of the geographical origins of G. rigescens, which indicated that the recognition results of HPLC and FTIR are consistent. Through HPLC–FTIR two-dimensional (2D) hetero-correlation analysis, the results showed a substantial correlation between HPLC and FTIR, which suggests that spectral correlative chromatography for multicomponent comparison can be conducted. In terms of G. rigescens, qualitative identification using FTIR is more convenient, rapid, environment-friendly and inexpensive than that using HPLC.