Quality Control of Herbal Medicines Assessed by NMR

The power of NMR in elucidating the structure of isolated natural or synthetic compounds is well established. In recent years, NMR has also become an important tool for the qualitative and quantitative analysis of complex mixtures such as herbal medicines. The combination of 1H NMR and multivariate analysis, quite often used in metabolomics, leads to a metabolite fingerprint that can be used for quality control and identification of the origin (e.g. geographical or supplier). Compared with other methods and despite its relatively low intrinsic sensitivity, NMR has the advantages of simple sample preparation, high robustness, and non-selectivity thus providing global information in a single analysis but also specific structural characterization. Several examples of the application of 1H NMR in the quality control of herbal materials will be reviewed for highlighting the usefulness, advantages and limitations of NMR. The article will conclude on the Diffusion Ordered Spectroscopy 1H NMR method that can be regarded as a “virtual chromatography” for screening adulterations of herbal medicines.