Quercetin is a promising pancreatic lipase inhibitor in reducing fat absorption in vivo

The inhibitory activity of quercetin on pancreatic lipase was investigated in both vitro and vivo. Quercetin exhibited inhibitory effect on pancreatic lipase with IC 50 value of 70 μg/mL. Inhibitory kinetics indicated that quercetin was more like a mixed-type (non-competitive) inhibitor of pancreatic lipase. Quercetin induced the endogenous fluorescence quenching of lipase, which suggested the interaction between them. The binding constant and the number of the binding sites were further calculated. Molecular docking results showed that quercetin had a binding site on lipase near the active pocket. The binding of quercetin on lipase would affect its conformation, thereby decreasing the affinity between the substrate and the enzyme. In vivo studies showed that pre-administration with 5 and 10 mg/kg bwt quercetin could significantly reduce fat absorption in rat. The inhibition of quercetin on lipase can last at least 2 h in vivo. Correspondingly, quercetin significantly increased fat excretion in rat feces. The change trends of fat and quercetin content in rat feces were similar. • Quercetin inhibited pancreatic lipase activity through binding on the non-competitive domain of enzyme. • Quercetinsignificantly reduced postprandial serum TG level in rat. • Quercetin significantly increase fat excretion in rat feces.