Original Research ARTICLE
Cysteine-rich peptide fingerprinting as a general method for herbal analysis to differentiate Radix Astragali and Radix Hedysarum
- 1Nanyang Technological University, Singapore
Species misidentification and adulteration are major concerns in authenticating herbal medicines. Radix Astragali (RA), the roots of Astragalus membranaceus, is a traditional herbal medicine used for treating diabetes. However, it is often substituted by Radix Hedysarum (RH), the roots of Hedysarum polybotrys from the same plant family Fabaceae, which possesses different bioactivities. Current authentication methods, focusing on the chemical composition differences of herbal medicines based on small molecules, have limitations when these chemical markers are found in many species. Herein, we describe a rapid and general method using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), coupled with multivariate analyses to differentiate herbal medicines. We used cysteine-rich peptide (CRP) fingerprinting, a method that exploits an underexplored chemical space between 2 to 6 kDa and which is populated by highly stable CRPs. To show the generality of the method, we screened 100 medicinal plant extracts and showed that CRP fingerprints are unique chemical markers. In addition, CRP fingerprinting was many-fold faster than the conventional authentication method using ultra-performance liquid chromatography (UPLC). Multivariate analyses showed that it has comparable classification accuracy as UPLC fingerprinting. Together, our findings revealed that CRP fingerprinting coupled with multivariate analyses is a rapid and general method for authentication and quality control for natural products in medicinal plants.
Keywords: Radix astragali, Radix Hedysarum, fingerprinting, Cysteine-rich peptides, multivariate analysis, MALDI-TOF MS, herbs
Received: 26 Apr 2019;
Accepted: 11 Jul 2019.
Edited by:Aleš Svatoš, Max Planck Institute for Chemical Ecology, Germany
Reviewed by:José J. Ordaz-Ortiz, Center for Research and Advanced Studies (CINVESTAV), Mexico
Alfredo J. Ibáñez, Pontificia Universidad Católica del Perú, Peru
Copyright: © 2019 Huang, Wong, Tay and Tam. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Prof. James P. Tam, Nanyang Technological University, Singapore, 639798, Singapore, JPTam@ntu.edu.sg