Authenticity and quality evaluation of different Rhodiola species and commercial products based on NMR-spectroscopy and HPLC.

INTRODUCTION: The main concern regarding the authenticity and quality of Rhodiola rosea L. (Sedum rosea (L.) Scop.) products is their adulteration with other Rhodiola species. OBJECTIVE: The aim of the study was the development of a reliable and practical analytical platform for quality and quantity assessment of the characteristic molecules in three Rhodiola species (R. rosea, R. kirilowii (Regel) Maxim and R. crenulata (Hook. f. & Thomson) H. Ohba), commercial products and their possible application as markers for the authentication of R. rosea based products. MATERIAL AND METHODS: The major molecules were identified by one-dimensional (1D) and two-dimensional (2D) nuclear magnetic resonance (NMR)-based metabolomics and quantitatively determined by high-performance liquid chromatography ultraviolet (HPLC-UV) analysis. The orthogonal projections to latent structures discriminant analysis (OPLS-DA) revealed the specific patterns in the metabolite profiles of R. rosea and R. crenulata. RESULTS: The coumarin crenulatin was only identified in R. crenulata and can be used as a marker to detect potential adulteration of the commercial products. Crenulatin was identified in two of the four analysed products by NMR-spectroscopy. According to the HPLC data, in less than a quarter of all products, the labelled amounts of salidroside and total rosavins were confirmed. CONCLUSIONS: The developed analytical platform was found to be useful in the investigations of the phytochemical diversity of different Rhodiola species, the recognition of the unique metabolites between them and the identification of adulterated products. Therefore, this approach could be applied from the earliest to the latest stages of the value chain in the manufacturing of R. rosea based products.