Inhibitory Effect and Mechanism of Ethyl p-hydroxycinnamate on Pancreatic Lipase

In order to explore lipid lowering activity of ethyl p-hydroxycinnamate, enzyme reaction kinetics and molecular docking techniques were used to study the inhibitory type and mechanism of ethyl p-hydroxycinnamate on pancreatic lipase. The kinetics results showed that ethyl p-hydroxycinnamate was a reversible competitive inhibitor of pancreatic lipase (semi-inhibitory concentration IC₅₀ was 41.07 μg/mL), with the maximum reaction rate V_max of 2.61 μmol/L·min and the inhibitory constant K_i of 114.35 μg/mL. Molecular docking results showed that ethyl p-hydroxycinnamate could form a strong hydrogen bond with the amino acid residues Ser152 and His263 in the triplet catalyzed by pancreatic lipase. Ethyl p-hydroxycinnamate could interacted with the amino acid residues of pancreatic lipase through Van der Waals force, hydrogen bond force, and competed with the substrate p-NPB for the active site of the enzyme. This study provided a theoretical basis for the application of ethyl p-hydroxycinnamate in functional foods.