Metabolomic Profile of Aqueous Extracts of Commercial Samples of St John's Wort (Hypericum perforatum) Determined by 1H NMR.

This study aimed to characterize the metabolomic profile of aqueous extracts of Hypericum perforatum (St. John's wort) commercial samples using 1H NMR spectroscopy, in order to evaluate their chemical composition as consumed in infusion form. Seven retail samples were extracted with water under conditions simulating tea preparation and analyzed using 1H NMR. Metabolite identification and quantification were performed with Chenomx® software, followed by multivariate statistical analyses including PCA and OPLS-DA. A total of 37 metabolites were identified, predominantly primary metabolites such as sugars (glucose, fructose), amino acids (glycine, asparagine), short-chain organic acids (malic, citric, and acetic acids), secondary metabolites (trigonelline, chlorogenic acid) and metabolism products (methanol, ethanol, acetic acid and acetone). Notably, key bioactive compounds traditionally associated with H. perforatum, such as hypericin and hyperforin, were not detected under the experimental conditions employed. Multivariate analyses revealed significant variability among samples, suggesting differences in composition likely related to origin, processing, or potential adulteration. These findings demonstrate that aqueous preparations of St. John's wort differ substantially from extracts used in clinical trials, being dominated by primary metabolism rather than specialized bioactive compounds. This has important implications for the interpretation of its therapeutic effects when consumed as tea. Furthermore, the study highlights the utility of NMR-based metabolomics as a robust tool for quality assessment and authentication of herbal products.