Enhanced water dispersibility and Caco-2 cell monolayer permeability of quercetin by complexation with casein...

Although quercetin (Que) has many beneficial therapeutic effects on the human body, its oral bioavailability is poor because of its low water solubility. Herein, we describe the preparation of casein hydrolysate (Pep_cas ) and its use as a dispersant to enhance the water dispersibility of Que resulting in an improvement of its bioavailability. By complexation with Pep_cas , the apparent solubility of Que in the complex (Que@Pep_cas ) was significantly increased under acidic and neutral conditions. Que@Pep_cas was pre-digested in vitro using a simulated digestive juice, and a Caco-2 cell monolayer permeation assay was performed to evaluate the oral bioavailability of Que. The cumulative amount of Que that permeated the monolayer using Que@Pep_cas after 8, 16, and 24 h was increased compared with a blank sample (Que@Blank), and the apparent permeation coefficient P_app of Que@Pep_cas was approximately 2.6-fold better than that of Que@Blank. PRACTICAL APPLICATION: Pep_cas can be used as a high absorption supplement and food additive, and our Pep_cas complexation technique should be widely applicable to not only Que but also to other poorly water-soluble substances.