Pyroglutamylproline purified from fermented barley extract increases ABCG2 expression in Caco-2 cells

Fermented barley extract P (FBEP) prepared from barley shochu distillation by-product has been reported to lower serum uric acid (UA) by increasing urinary excretion of UA. ATP-binding cassette subfamily G member 2 (ABCG2) is a transporter responsible for UA efflux from the intestinal tract and kidneys. This study aimed to identify, among the compounds isolated from FBEP using high-performance liquid chromatography, the components that promote ABCG2 expression in Caco-2 cells. Pyroglutamylproline (pEP) increased the expression of ABCG2 in Caco-2 cells at the gene and protein levels. These results suggest that the pEP contained in FBEP may decrease serum UA levels by increasing the expression of urate efflux transporters in the intestinal epithelium and promoting UA excretion.