A targeted mass spectrometric approach to evaluate the anti-inflammatory activity of the major metabolites of Foeniculum vulgare Mill. waste in human bronchial epithelium

Cell metabolomics offers deep insights into the mechanisms through which plant-derived bioactive compounds contribute to the prevention and mitigation of various diseases by modulating key metabolic pathways. The respiratory system is highly vulnerable to inflammation, with acute viral infections posing a significant global health risk. While many are mild and self-resolving, some can become severe. Lower respiratory tract infections—like bronchiolitis, pneumonia, and asthma or COPD exacerbations— can lead to respiratory failure, serious complications, death, and lasting cardiovascular or neurological effects [ 1 ]. Given the anti-inflammatory properties of plant secondary metabolites, this study aimed at investigating the capacity of selected compounds extracted from Foeniculum vulgare waste to modulate the eicosanoid and sphingolipid inflammatory mediator pathways, in the respiratory tract [ 2 ]. Human bronchial epithelial cells (BEAS-2B cell line) were treated with quercetin-3- O -glucoside, quercetin-3- O -glucuronide, kaempferol-3- O -glucuronide, 1,5-dicaffeoylquinic acid, and quinic acid, isolated from fennel by-products. Inflammation was induced by IL-1β stimulation, after which the cell culture supernatants were collected for metabolite extraction and purification. Eicosanoids and sphingolipids were subsequently quantified using UPLC-ESI-QTRAP-MS/MS in multiple reaction monitoring (MRM) mode. This study presents an innovative metabolomics-based approach to elucidate the mechanisms of action of natural compounds in cellular models. The findings reveal that fennel waste, rich in polyphenolic compounds, can attenuate inflammation in human bronchial epithelial cells by enhancing the production of anti-inflammatory mediators while suppressing pro-inflammatory pathways. These results suggest that functional foods or nutraceuticals derived from fennel waste can be used as promising adjuvants in the control of chronic inflammatory respiratory diseases, including COPD and asthma ([ Fig. 1 ]). Fig. 1 Research workflow. Publication History Article published online: 05 March 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany