Figure 1.

Inhibition kinetics of porcine dipeptidyl peptidase-IV (DPP-IV) by resveratrol (a), luteolin (b), apigenin (c), and flavone (d). Different concentrations of the flavonoids (0, 5, and 10 μg/mL for luteolin, apigenin, and flavone and 0, 0.25, and 0.5 μg/mL for resveratrol) were incubated in the presence of various concentrations of Gly-Pro-AMC (0–60 μM) as substrate. Initial rates of the reaction were measured, and the results are expressed as a Lineweaver-Burk plot. Data are expressed as the mean of four independent experiments.