Enhanced brain delivery and antiproliferative activity of resveratrol using milk-derived exosomes

The polyphenol resveratrol (RSV) undergoes extensive phase II metabolism, which limits its bioavailability and bioactivity, including anticancer effects. Growing preclinical evidence reinforces milk-derived exosomes (EXOs) as promising nanocarrier drugs and bioactives delivery systems. Herein, to overcome the mentioned RSV's drawbacks, EXOs were loaded with RSV (EXO-RSV) to evaluate its brain delivery in Sprague-Dawley rats and its in vitro antiproliferative effects against human neuroblastoma SH-SY5Y and glioblastoma U-87MG cancer cells compared with non-encapsulated RSV. Pharmacokinetic analyses in perfused brains showed RSV detection only after EXO-RSV administration, not after non-encapsulated RSV administration. Encapsulation also resulted in lower concentrations of phase II-derived RSV metabolites in circulation. Additionally, blood-brain barrier (BBB) transport assays using human brain microvascular endothelial cells (HBMECs) corroborated that encapsulation enhanced RSV transport efficiency and protected it from cellular metabolism. In vitro and in silico analyses of phase-II conjugates, primarily RSV 3-glucuronide, showed lower capacity than RSV to cross the BBB. Finally, EXO-RSV (47−750 nM) showed an increased dose-dependent antiproliferative efficacy on both cancer cell lines compared with the non-encapsulated RSV (10 μM), which was ineffective after 72 h of treatment. Our findings suggest that EXOs protect RSV from phase II metabolism and enhance its brain delivery and antiproliferative activity.