Berry and Citrus Phenolic Compounds Inhibit Dipeptidyl Peptidase IV: Implications in Diabetes Management

Figure 3

Key interactions of resveratrol (A₁, A₂), flavone (A₁, A₃), luteolin (B₁, B₂), apigenin (B₁, B₃), quercetin (C₁, C₂), and genistein (C₁, C₃) with active sites of DPP-IV enzyme. Binding pose of resveratrol (A₁, green) and flavone (A₂, yellow) in the DPP-IV active site is indicated (surface view: blue), wherein two compounds interact closely with key residues of active sites S1, S2, and S3. Binding pose of luteolin (B₁, green), apigenin (B₁, yellow), quercetin (C₁, green) and genistein (C₁, yellow) in the DPP-IV binding site is indicated, wherein these flavonoids interact closely with the key residues of sites S2, and S3. Residues with pink circles indicate hydrogen-bond, or ionic or polar interactions, residues with green circles indicate Van der Waals interactions. The arrows indicate hydrogen bonds to side chain residues in blue and backbone residues in green.