Inhibitory activity of luteolin on α‐glucosidase and pancreatic lipase in vitro and in vivo

Summary Obesity is becoming a top global health problem. Inhibition of digestive enzymes is an effective approach in weight management due to the reduction of energy absorption. In this study, the inhibitory effects of luteolin on α‐glucosidase and pancreatic lipase were investigated in vitro and in vivo via enzyme kinetics, fluorescence quenching, molecular docking and rat experiments. The results showed that luteolin inhibited α‐glucosidase and pancreatic lipase in a mixed‐type and uncompetitive manner with IC 50 values of 29.31 and 42.74 μg mL −1 respectively. The binding of luteolin with the two enzymes caused the quenching of intrinsic fluorescence of protein. Molecular docking simulation revealed that luteolin could be located in the active pocket of α‐glucosidase and interact with the key amino acid residues. Moreover, a hydrophobic interaction and a van der Waals force were formed between luteolin and the key amino acid residues of pancreatic lipase (His264 and Ser153). In vivo studies further confirmed that luteolin could significantly decrease the absorption of glucose and triacylglyceride in rats by inhibiting α‐glucosidase and pancreatic lipase.