UHPLC-ESI-QTOF-MS phenolic profiling and antioxidant capacity of bee pollen from different botanical origin

In this work, bee pollen samples from different botanical origin were investigated for antioxidant capacity. Thereafter, a phenolic profiling was produced through a mass spectrometric untargeted metabolomic approach. Marked differences were identified in TPC, ranging from 4.2 (Magnolia) to 29.6 mg g(-1) GAE (Lamium). Wide differences were also recorded in antioxidant capacity (ORAC, ABTS and DPPH assays). Untargeted profiling allowed annotating 467 compounds with flavonoids being the most frequent class of phenolics followed by phenolic acids, tyrosols, lignans and other. OPLS-DA clearly discriminated the most represented floral families (Umbelliferae, Rosaceae and Fabaceae), suggesting, thus, that botanical origin leaves a characteristic phenolic signature in pollen. Overall, 35 phenolics accounted for most of the discrimination, with flavonoids being the most represented class. Despite the fact that further research is needed, the phenolic profile of bee pollen is a promising tool to investigate the botanical origin.