Biological Screening and IC₅₀ Determination of Novel DPP-4 Inhibitory Compounds via Fluorescence-Based Assay

Abstract

The present study focused on the biological evaluation of three newly synthesized DPP-4 inhibitor derivatives (D1, D2, and D3) using a fluorescence-based in vitro assay. The compounds were assessed for their ability to inhibit dipeptidyl peptidase-4 (DPP-4), an enzyme implicated in the degradation of incretin hormones and a validated therapeutic target for type 2 diabetes mellitus. The synthesized compounds demonstrated dose-dependent inhibition, with compound D2 exhibiting the highest potency (IC₅₀ = 1.45 µM), followed by D1 and D3. Teneligliptin was used as a reference standard, and while the new derivatives showed slightly lower activity, they displayed promising potential for further optimization. The results, supported by HPLC and DSC data, confirm both the biological activity and chemical stability of the compounds, suggesting their suitability for preclinical development.