Discrimination of geographical origin and adulteration of radix astragali using fourier transform infrared spectroscopy and chemometric methods.

INTRODUCTION

Radix Astragali, one of most widely used and important traditional Chinese medicines, is cultivated in different geographical regions. Because of varying growing conditions, the qualities of Radix Astragali vary, which can give rise to differences in clinical therapy. Detecting adulteration is a routine requirement in pharmaceutical practice.

OBJECTIVE

To develop a simple and accurate approach to discriminate the geographical origin and potential adulteration of Radix Astragali, derived from the root of Astragalus membranaceus (Fischer) Bunge var. mongholicus (Bunge) Hsiao, using Fourier transform infrared (FT-IR) spectroscopy and chemometric methods.

METHODOLOGY

To obtain characteristic IR spectra for accurate discrimination, a one-solvent extraction method was utilised following a novel evaluation method for selecting appropriate solvents. Samples of Radix Astragali from different geographical origins were discriminated using FT-IR spectroscopy and discriminant partial least squares (DPLS) methods. FT-IR spectroscopy combined with Mahalanobis distance was employed to detect adulteration of Radix Astragali.

RESULTS

In comparison with other solvents, butanone was more effective at extracting samples. Radix Astragali samples were accurately assigned to their corresponding geographical origins by using FT-IR spectroscopy and DPLS method. Most adulterated samples were detected accurately by application of FT-IR spectroscopy combined with Mahalanobis distance.

CONCLUSION

FT-IR spectroscopy combined with chemometric method was developed and demonstrated to be a useful tool to discriminate geographical origin and adulteration of Radix Astragali.