Beyond the label: Metabolomic analysis reveals quality variability in commercial Hyssopus officinalis essential oils

Hyssopus officinalis L. (Lamiaceae) essential oils (EOs) are renowned for their complex chemical composition and diverse chemotypes, which hold significant value in traditional and modern medicine, aromatherapy, pharmaceuticals, and as natural preservatives [ 1 ] [ 2 ]. This study analysed 20 commercial EO samples from the aerial parts of Hyssopus officinalis subsp. officinalis , sourced from Italy, Spain, France, and Bulgaria. Chemical characterization was conducted using GC-MS-FID and 1 H NMR-based metabolomics, identifying two primary chemotypes: eucalyptol and pinocamphones ( cis- and trans -), and a third linalool chemotype. The pinocamphones chemotype was further divided into two groups, one with a high β-phellandrene content. The biological properties of the EOs were evaluated for antifungal activity against Trichophyton mentagrophytes and T. violaceum , and antioxidant potential using the DPPH test. The pinocamphones chemotype with high β-phellandrene exhibited the highest antioxidant activity (IC 50 =3.24 μl/ml) and significant antifungal activity, inhibiting T. mentagrophytes by 28% and T. violaceum by 15%. The eucalyptol chemotype showed negligible antifungal activity, except for one sample with 55% inhibition of T. mentagrophytes , distinguished by high aromatic or olefinic compound concentration. Multivariate data analysis provided an overview of the global phytochemical and biological results, emphasizing the need for detailed quality control procedures for commercial EOs, especially given the diverse chemotypes with varying bioactivities and organoleptic properties. This study highlights the potential presence of fraud in the EO market, underscoring the importance of rigorous quality control measures. The predictive OPLS-DA model presented in this study offers a valuable tool for EO quality control. Publication History Article published online: 05 March 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany