Rapid and Nondestructive Identification of the Geographical Origin of Ophiopogonis Radix by Raman Spectroscopy and Multivariate Statistical Analysis

The pharmacological activity and clinical efficacy of traditional Chinese medicine (TCM) are significantly influenced by the geographical origin. Therefore, the effective and reliable identification of TCM producing regions is crucial for the quality control and clinical application of TCM. Ophiopogonis Radix (Chinese name: Maidong (MD)) is a well-known TCM with various properties, such as anti-oxidation, anti-inflammation, anticancer, and cardiovascular protection. In this study, the feasibility of Raman spectroscopy combined with partial least squares discriminant analysis (PLS–DA) to distinguish Sichuan Ophiopogonis Radix (CMD) from Zhejiang Ophiopogonis Radix (ZMD) was investigated. Extensive experimental results demonstrated that the Raman peaks at 363, 465, 1345, 1458, 2893 and 2933 cm⁻¹ corresponding to polysaccharides, homoisoflavonoids, and steroidal saponins could be used as identification chemical markers for CMD and ZMD. Additionally, the PLS–DA-based scheme proposed in this study could identify the geographical origins of CMD from ZMD with an accuracy of 92.7%. Unlike conventional morphological and microscopic identification and physicochemical analysis, the proposed method is nondestructive, involves simple sample preparation, requires a very low mass of the sample, and exhibits a high classification accuracy to discriminate between CMD and ZMD. Therefore, despite analyzing a limited number of samples, this study proposes a method by the combination of Raman spectroscopy and PLS–DA to rapidly, sensitively, and nondestructively discriminate Ophiopogonis Radix samples with different geographical origins. This study confirms that Raman spectroscopy exhibits high potential to facilitate the authentication, quality control, and supervision of herbal medicines and processed products.