Protecting the power of organic propolis: microencapsulation preserves phenolic bioactivity through digestion and intestinal transport

Propolis is a resinous substance produced by bees, known for a wide range of biological activities, including antimicrobial, anti-inflammatory, and antioxidant properties. This study focused on organic propolis Type 1 (OP1), collected from the native forest of General Carneiro, Paraná, Brazil. The ethanolic extract of OP1 was microencapsulated in three formulations: extract + gum arabic by spray drying (GA + OPE), extract + vegetable fat by spray chilling (VF + OPE), and extract + gum arabic + vegetable fat by spray drying (GA + VF + OPE). Particles were characterized for physical properties and subjected to in vitro gastrointestinal digestion, followed by epithelial transport assays using Caco-2 monolayers. Bioaccessible and basolateral fractions were analyzed by LC-ESI-QTOF-MS, and antioxidant activity was assessed against reactive oxygen species. The anti-inflammatory potential was evaluated in RAW 264.7 cells transfected with a luciferase reporter gene by measuring NF-κB activation, TNF-α secretion, and CXCL2/MIP-2 production. Chemical analysis revealed a predominance of lignans and phenolic acids, with distinct release kinetics among formulations during digestion. GA + VF + OPE particles showed significantly higher antioxidant activity (p < 0.05) against peroxyl radicals and hypochlorous acid and demonstrated superior anti-inflammatory effects by inhibiting NF-κB activation (28 %) and TNF-α secretion (53 %) at 100 μg propolis/mL. In conclusion, the encapsulation strategies preserved the bioactive properties of OP1, with GA + VF + OPE particles emerging as the most promising formulation. Future studies should explore their incorporation into functional food products.