Butenolide-based human carbonic anhydrase (hCA) I/II inhibitors: integrated computational and biological evaluation

This study aimed to evaluate the inhibitory effects of a series of butenolide derivatives on human carbonic anhydrase isoenzymes I and II (hCA I and hCA II) and to investigate their antioxidant and antimicrobial properties through experimental and computational approaches.

Butenolide derivatives (2a-2j) were evaluated for their inhibitory activity against hCA I and hCA II using in vitro enzyme inhibition assays. Antioxidant activities were assessed using ABTS•⁺ radical scavenging and Fe³⁺ reducing assays, while antimicrobial activities were determined using the disc diffusion method against selected Gram-positive, Gram-negative bacteria and fungal strains. Molecular docking, Prime/MM-GBSA binding free energy calculations, and molecular dynamics simulations were performed to investigate ligand - enzyme interactions and binding stability.

Among the tested compounds, derivative 2c showed the most potent inhibition against hCA I and hCA II with K_i values of 0.212 ± 0.018 μM and 0.051 ± 0.015 μM, respectively, exceeding the activity of the reference inhibitor acetazolamide. Antioxidant assays indicated that compound 2h exhibited the strongest radical scavenging and reducing activity. Several derivatives demonstrated moderate antibacterial activity, whereas limited antifungal activity was observed. Computational studies supported the experimental findings and revealed stable ligand - enzyme interactions.

The results suggest that butenolide derivatives represent promising multifunctional scaffolds for the development of new carbonic anhydrase inhibitors with additional antioxidant and antimicrobial potential.