In vitro and in vivo inhibitory activity of taxifolin on three digestive enzymes.

The inhibitory activity of taxifolin on three digestive enzymes were investigated in both vitro and vivo. Taxifolin exhibited inhibitory effect on α-glucosidase, α-amylase and pancreatic lipase with IC50 values of 0.038, 0.647 and 0.993 mg/mL, respectively. Inhibitory kinetics indicated that taxifolin was more like a competitive inhibitor of α-glucosidase and α-amylase, while it was a non-competitive inhibitor of pancreatic lipase. The binding of taxifolin caused the quenching of intrinsic fluorescence intensity of enzymes, and the binding constant (lgKa) and the number of binding site (n) were further calculated through fluorescence titration. The values of lgKa were in the range of 4.93-6.65, and the values of n were all close to 1. Molecular docking indicated that taxifolin could interact with α-glucosidase and α-amylase through many kinds of secondary interaction, such as hydrogen bond, π-π stack, etc. In vivo study revealed that pre-administration with taxifolin can significantly improve the postprandial hyperglycemia in rat. Furthermore, its can also decrease triglyceride absorption through the inhibition of pancreatic lipase.