Bee pollen from bracatinga (Mimosa scabrella): Effects of gastrointestinal digestion and epithelial transport in vitro on phenolic profile and bioactivities.

Abstract

The main objective of the present work was to assess the phenolic profile of bracatinga (Mimosa scabrella) bee pollen, and its antioxidant and anti-inflammatory activities after gastrointestinal digestion in vitro and epithelial transport in a Caco-2 cell monolayer model. The botanical origin of bee pollen was confirmed by optical microscopy and scanning electron microscopy. As major results, 34 phenolic compounds (13 phenylamides, 14 flavonols, and 7 flavanones) were tentatively identified in the extract of bracatinga bee pollen by HPLC-ESI-QTOF-MS. The aglycone forms of quercetin and p-coumaric acid were identified only after digestion, indicating the breakage of flavonols and phenylamides, respectively. These compounds may have contributed to the decrease in NF-κΒ activation up to 54% and in the release of TNF-α and CXCL2/MIP-2 by 26% and 21%, respectively, in raw 264.7 murine macrophages activated with microbial lipopolysaccharide and treated with the digested fraction. Among all tentatively identified phenolic compounds, five of them were found in the basolateral fraction. These compounds, represented by four aglycone flavonoids (quercetin, kaempferol, naringenin, and herbacetin methyl ether) and a phenolic acid (p-coumaric acid) may be responsible for its outstanding antioxidant activity in Caco-2 cells, as well as for its remaining capacity in mitigating CXCL2/MIP-2 release after transport through the Caco-2 cell monolayer, as an intestinal barrier model. Therefore, our work sheds light on the phenolic profile and bioactivities of an interesting functional food produced by bees throughout a simulated gastrointestinal system.