A quercetin nanoemulsion enhances oral bioavailability and hepatic accumulation of quercetin (1044.19)

Quercetin (Q) has antioxidant activity but poor bioavailability. We examined whether a quercetin nanoemulsion (NQ) improved Q bioavailability and its hepatic accumulation. Rats received NQ or unformulated Q (UQ; 30 mg/kg BW) by gavage prior to collecting plasma at timed intervals for 24 h to measure Q and its methylated metabolites isorhamnetin (ISO) and tamarixetin (TAM). Rats receiving NQ or UQ were also sacrificed at 4 or 24 h to measure liver Q, ISO, and TAM. Compared to UQ, NQ increased ( P <0.05) maximum plasma Q (21.5 ± 5.1 vs 7.7 ± 2.0 µM) and Q bioavailability (AUC 0‐24 h : 130.4 ± 30.9 vs 57.2 ± 19.6 µM x h). NQ decreased Q time to maximum concentration (0.9 ± 0.3 vs 3.8 ± 1.0 h, P <0.05) while increasing Q half‐life (7.2 ± 1.1 vs 4.5 ± 0.5 h, P <0.05). Plasma pharmacokinetics of ISO and TAM were unaffected by NQ. NQ increased liver Q (233 ± 28 vs 159 ± 28 pmol/g) and liver ISO (120 ± 14 vs 78 ± 15 pmol/g) to a greater extent at 4 h than UQ whereas hepatic Q and ISO were similarly lowered at 24 h without any group differences. Liver TAM at 4 h did not differ between groups nor was it detected at 24 h in either group. Plasma alanine transaminase and creatinine were unaffected by both treatments. Collectively, NQ improves Q oral bioavailability without inducing acute liver or renal injury. Further study is needed to examine whether greater hepatic accumulation of Q or ISO potentiates their antioxidant activity. Grant Funding Source : Supported by the Diet and Health Initiative at University of Connecticut