Metabolic characterization of seven bee pollens: Molecular network, metabolite isolation and antioxidant activity assessment

In a changing world, bees are facing increasing stressful conditions, such as ozone and pollutant concentrations, and more events of higher temperatures [ 1 ] [ 2 ] [ 3 ]. Vanderplanck et al., coordinating the BeeMed project, suggested that bees may develop an auto-medication behaviour by selecting the species that may provide them the most beneficial pollen content, notably antioxidant metabolites [ 4 ]. The objective of this study, part of the BeeMed project, was to characterize the metabolic content of bee pollens from five dominant species ( Prunus sp., Cistus sp., Malus sp., Salix sp., Taraxacum officinale ) and two mix of species (fruit trees, multifloral). A Featured-Based Molecular Network (FBMN) was realized after UHPLC-MS/MS analysis to underscore the occurrence of species metabolites. Major metabolites from the Prunus -dominant pollen were purified by Centrifugal Partition and preparative chromatographies for further chemical characterization (1D and 2D NMR). Extracts and purified metabolites were assessed for their antioxidant properties using an online-antioxidant ABTS assay. Three main spectral families were detected in all bee pollen, namely polyamines (ex: spermidines, spermines), flavonoid glycosides and amino-acids. Specific benzylisoquinoline alkaloids (ex: scoulerin and derivatives) were exclusively detected in Cistus -dominant pollen. Isorhamnetin dihexoside, displaying antioxidant properties, and isorhamnetin hexoside were purified from Prunus -dominant pollen and structurally confirmed. Myricetin dihexoside and p -coumaroyl dicaffeoyl spermidine isomers demonstrated the best antioxidant activities. The use of three complementary approaches (MS-based FBMN, metabolite purification and anti-oxidant assay) led to a better description of pollen chemical diversity and pave the way for further experiments to better understand bee resilience facing oxidative stresses. Publication History Article published online: 05 March 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany