Role of Extracellular Vesicles in Absorption and Functional Mechanisms of Quercetin.

SCOPE: Quercetin (QUE), a phytochemical found in various plant foods, has been shown to have a variety of physiological activities in vivo, though biological sites where it has activities and the mechanisms of transport have not been fully elucidated. METHODS AND RESULTS: In the present study, intracellular uptake of QUE into HT-29 human colon adenocarcinoma cells is found to result in spontaneous release of extracellular vesicles (EVs), which are subsequently embedded with QUE. In addition, QUE-embedded EVs are detected in serum of QUE-administered Sprague-Dawley rats. Interestingly, the rate of cellular uptake of QUE-encapsulated EVs (EV-QUE) into RAW264.7 macrophages is markedly higher than that of free QUE. Moreover, EV-QUE suppresses lipopolysaccharide (LPS)-induced nitric oxide at a lower concentration than free QUE. CONCLUSION: The present findings suggest that QUE may be embedded in EVs in the gastrointestinal tract, then become absorbed and enter the bloodstream to exhibit biological activities.

Transfer of quercetin ingested by maternal mice to neonatal mice via breast milk.

This is the first study that quantified quercetin (QUE) and its 16 metabolites in the breast milk of QUE-fed maternal mice, the plasma and urine of that, and neonatal mice. Interestingly, the QUE aglycone concentration in the milk was much higher than in the plasma of maternal mice, suggesting that QUE may exert biological activity in neonates.