DPP-IV Inhibitory Phenanthridines: Ligand, Structure-Based Design and Synthesis

Area of Science:

• Medicinal Chemistry
• Computational Chemistry
• Pharmacology

Background:

• Diabetes mellitus is a major global health concern, driving the need for novel oral antidiabetic agents.
• Dipeptidyl peptidase-IV (DPP-IV) inhibitors represent a significant class of oral antidiabetic drugs.
• Previous DPP-IV inhibitors included various chemical scaffolds, highlighting ongoing research for new therapeutic options.

Purpose of the Study:

• To develop a pharmacophore model for dipeptidyl peptidase-IV (DPP-IV) inhibitors.
• To evaluate phenanthridines as a novel scaffold for DPP-IV enzyme inhibition.
• To assess the binding interactions of phenanthridine derivatives with the DPP-IV enzyme active site using molecular docking.

Main Methods:

• Ligand-based pharmacophore modeling and Quantum-Polarized Ligand Docking (QPLD) were employed.
• Three novel 3,8-disubstituted-6-phenyl phenanthridine derivatives were synthesized and characterized.
• In vitro DPP-IV inhibitory activity was assessed using a fluorometric assay.

Main Results:

• QPLD revealed hydrogen bonding and charge transfer interactions between phenanthridine derivatives and DPP-IV active site residues (Lys554, Trp629, Tyr631, Tyr547, Tyr666).
• The synthesized compounds fit the established pharmacophore model for DPP-IV inhibitors.
• Compound 5 exhibited significant in vitro DPP-IV inhibition (45.4% at 100 μM).

Conclusions:

• Phenanthridines show promise as a novel lead scaffold for developing effective DPP-IV inhibitors.
• These findings support the potential of phenanthridine derivatives as new antidiabetic agents.
• Computational analysis suggests avenues for future structural simplification to optimize inhibitory activity.