Identification of four Sedum plant medicines by Fourier transform infrared spectra

Background: Sedum sarmentosum bunge (SSB)., S. lineare Thunb. (SLT), S. erythrostictum migo. (SEM), and S. aizoon L. (SAL) were four widely used Chinese traditional drugs or ethnic drugs, which were easy to be confused with each other. Objective: This study aimed at developing a rapid and accurate method to identify the four Sedum plant medicines with very similar appearances and close relationships. Materials and Methods: The herbal medicines employed here were SSB, SLT, SEM, and SAL collected in different places and seasons. Through comparing the infrared (IR) spectra of their 70% ethanol extracts, the results showed that the IR spectra of the four plant medicines possessed not only some common characteristics but also certain notable distinctions, such as shapes, numbers, positions, intensity, and ratios of the absorbing peaks. Results: By Fourier transform infrared (FT-IR) spectroscopy, the four medicines could be effectively differed, their habitats could be judged preliminarily, and the genetic relationships of the original plants of the four medicines could also be estimated to some extent. Conclusion: The application of FT-IR spectroscopy in crude medicine authentication and quality evaluation deserved to be further emphasized.