Proceedings of International Congress on Bioactive Compounds and International Workshop on Bioactive Compounds
Proceedings of 2nd International Congress on Bioactive Compounds

The Brazilian red propolis (BRP) is produced by Apis mellifera bees in the mangrove biome with resins from the Dalbergia ecastaphyllum and Symphonia globulifera L.f.. This propolis shows high antioxidant and anti-inflammatory activities that are related to its phenolic compounds, mainly flavonoids. Considering the relative stability of flavonoids to variations on temperature and pH, the encapsulation process may help to preserve the BRP bioactive compounds throughout the gastrointestinal tract, as well as to mitigate propolis bitter taste. In this context, agri-food residues have been studied as affordable and sustainable encapsulating materials. Thus, the objective was to evaluate the effects of in vitro gastrointestinal digestion and cell-based small intestinal epithelial transport on anti-inflammatory activities of BRP encapsulated with brewery waste Saccharomyces cerevisiae. The red propolis was extracted with EtOH 80% at 50ºC for 30 minutes. The obtained ethanolic extract of propolis (EEP) and a powdered yeast of Saccharomyces cerevisiae were homogenized, submitted to biosorption, and spray dried. The particles were submitted to in vitro gastrointestinal digestion, based on the INFOGEST protocol (Brodkorb et al., 2019), and the digested fraction (DF) was conducted to a Transwell plate with a Caco-2 cell monolayer to simulate small intestinal transport (Hubatsch et al., 2007), and the basolateral fraction (BF) was collected. The EEP, DF, and BF samples were analyzed by LC-ESI-QTOF-MS to monitor the bioactive compounds. The anti-inflammatory assay was performed with RAW 264.7 macrophages transfected with NF-kB-pLUC gene to access NF-kB transcription factor activation, and ELISA assays to quantify TNF-α and CXCL2/MIP-2. As results, 21 compounds were found in the samples (flavanones, isoflavonoids, flavones, and one chalcone): 17 in the EEP, 12 in the DF, and 7 in the BF. The fraction of the total phenolic content (TPC) transported through the Caco-2 cell monolayer corresponded to 6% of the TPC found in the EEP. The anti-inflammatory assays showed that NF-κB activation was significantly reduced (p < 0.05) by EEP in the macrophages (89% at 30 μg/mL). However, this activity was lost after in vitro digestion, although it was observed after epithelial transport, with the BF at 1,500 μg/mL reducing NF-κB activation by 65 % (p < 0.05). Furthermore, the EEP reduced significantly the TNF-α release (81% at 30 μg/mL) (p < 0.05). The DF tested concentrations did not reduce TNF-α release, while the BF had this anti-inflammatory effect (38% at 1,500 μg/mL). The CXCL2/MIP-2 release was not reduced in macrophages treated with EEP or DF (p < 0.05). However, a significant reduction was observed in macrophages pre-treated with the BF (25% at 1,500 μg/mL) (p < 0.05). Therefore, there is indication that the ethanolic extract of Brazilian red propolis encapsulated with brewery waste Saccharomyces cerevisiae exerts bioactivity as anti-inflammatory even after small intestinal absorption. Therefore, it is a promising ingredient for functional food formulations.