Herbal preparations traditionally used in upper respiratory tract infections: UHPLC-DAD-ESI–MS/MSn phytochemical profiling and anti-inflammatory activity in human immune cell models

Upper respiratory tract infections (URTIs) constitute a major global health concern, accounting for a substantial proportion of primary care visits and pharmaceutical consultations each year. Clinically, URTIs manifest with symptoms such as rhinitis, pharyngitis, laryngitis, cough, and fever, with considerable variability in severity and duration. In light of the limitations associated with conventional treatment strategies and the growing threat of antibiotic resistance, plant-based preparations have attracted increasing scientific interest as complementary therapeutic approaches. However, despite a long tradition of use, comprehensive studies integrating detailed phytochemical characterisation with functional assessment of their immunomodulatory effects on human innate immune cells remain limited. The present study aimed to characterise the phytochemical composition and evaluate the anti-inflammatory potential of aqueous and ethanolic extracts derived from ten medicinal plants traditionally used in the treatment of URTIs. Extracts were profiled by UHPLC-DAD-ESI–MS/MSn and evaluated for biological activity using human PBMC-derived monocytes/macrophages and neutrophils isolated from healthy donors as in vitro models of innate immune response. The anti-inflammatory activity was evaluated by quantifying pro-inflammatory cytokine secretion (TNF-α, IL-1β, IL-6, IL-8), reactive oxygen species (ROS) generation, and surface expression of β₂ integrins (Mac-1, LFA-1). Phytochemical profiling revealed marked differences in the composition of aqueous (infusion) and ethanolic (tincture) extracts, reflecting the influence of the extraction solvent on the selective enrichment of distinct compound classes. These compositional differences translated into distinct biological activity profiles, with individual extracts exhibiting differential potency and cell-type specificity. Collectively, these findings provide a scientific rationale for the traditional use of the investigated plant species in the management of URTIs and highlight their potential as evidence-based complementary interventions modulating the innate immune response. The observed cell-type selectivity and differential potency of the tested preparations warrant further investigation to identify the key bioactive constituents responsible for the reported effects and to elucidate their precise molecular mechanisms of action.