Hoti, Dafina; Nixha, Arleta Rifati; Duran, Hatice Esra; Arslan, Mustafa; Yıldıztekin, Gizem; Ece, Abdulilah; Türkeş, Cüneyt

Aldose reductase (ALR2; AKR1B1) is implicated in hyperglycemia-driven tissue injury and remains a tractable enzymatic target. We developed a concise, chromatography-free two-step route to phthalimide–benzoic acid hybrids ( 5a–5m) and profiled their biochemical activity against human ALR2. Across the series, halogenated analogs were most active, with the para-bromophenyl derivative5demerging as the top hit (KI = 7.56 nM). Steady-state kinetic analysis indicated a competitive inhibition mechanism. Molecular docking to the ALR2 active site (PDB4JIR), supported by MM-GBSA rescoring, yielded a catalytically consistent binding mode featuring hydrogen-bonding within the anion-binding region (Tyr48, His110) and complementary hydrophobic contacts (Trp111, Trp219), with Cys298 contributing as a proximal hydrophobic contact. In cell-based assays (A549, Hep3B, L929), the compounds generally showed low intrinsic cytotoxicity at the tested concentrations, suggesting a favorable preliminary safety margin aligned with their ALR2-directed pharmacology. In silico ADME/Tox assessments further supported oral drug-likeness. Overall, these results identify phthalimide–benzoic acid hybrids as tractable ALR2 inhibitor scaffolds that combine potent biochemical inhibition with a competitive kinetic profile and encouraging early safety signals, warranting in vivo evaluation and SAR-guided optimization.

Kakakhan, Chnar; Türkeş, Cüneyt; Güleç, Özcan; Demir, Yeliz; Arslan, Mustafa; Özkemahlı, Gizem; Beydemir, Şükrü

A novel series of 1,2,3-triazole benzenesulfonamide substituted 1,3-dioxoisoindolin-5-carboxylate (7a-l) inhibitors of human α-carbonic anhydrase (hCA) was designed using a tail approach. The design method relies on the hybridization of a benzenesulfonamide moiety with a tail of 1,3-dioxoisoindoline-5-carboxylate and a zinc-binding group on a 1,2,3-triazole scaffold. Among the synthesized analogues, 2‑iodophenyl (7f, KI of 105.00 nM and SI of 2.98) and 2‑naphthyl (7h, KI of 32.11 nM and SI of 3.48) analogues (over off-target hCA I) and phenyl (7a, KI of 50.13 nM and SI of 2.74) and 2,6‑dimethylphenyl (7d, KI of 50.60 nM and SI of 3.35) analogues (over off-target hCA II) exhibited a remarkable selectivity for tumor isoforms hCA IX and XII, respectively. Meanwhile, analogue 7a displayed a potent inhibitory effect against the tumor-associated isoform hCA IX (KI of 18.29 nM) compared with the reference drug acetazolamide (AAZ, KI of 437.20 nM), and analogue 7h showed higher potency (KI of 9.22 nM) than AAZ (KI of 338.90 nM) against another tumor-associated isoform hCA XII. However, adding the lipophilic large naphthyl tail to the 1,3-dioxoisoindolin-5-carboxylate analogues increased both the hCA inhibitory and selective activities against the target isoform, hCA XII. Additionally, these analogues (7a-l) showed IC50 values against the human lung (A549) adenocarcinoma cancer cell line ranging from 129.71 to 352.26 μM. The results of the molecular docking study suggested that the sulfonamide moiety fits snugly into the hCAs active sites and interacts with the Zn2+ ion. At the same time, the tail extension engages in various hydrophilic and hydrophobic interactions with the nearby amino acids, which affects the potency and selectivity of the hybrids.

Coban, T. Abdülkadir; Beydemir, Şükrü; Gülcin, Ilhami; Ekinci, Deniz; Innocenti, Alessio; Vullo, Daniela; Supuran, Claudiu T.

Alp, Cemalettin; Ekinci, Deniz; Gültekin, Mehmet Serdar; Şentürk, Murat; Şahin, Ertan; Küfrevioǧlu, Ömer Irfan

Here we propose a novel one-pot synthesis of new tosyl-pyrrole derivatives. By means of the new developed method, pyrrole derivatives were synthesized at room temperature in a single step, and a useful method is proposed for the synthesis of similar compounds. Moreover, inhibitions of two human cytosolic carbonic anhydrase (hCA, EC 4.2.1.1) isozymes I and II by 1-tosyl-pyrrole and 1-tosyl-pyrrol-2-on derivatives were investigated. 1-Tosyl-pyrrole, 1-tosyl-1H-pyrrol-2(5H)-one, 5-hydroxy-1-tosyl-1H-pyrrol-2(5H)-one and 5-oxo-1-tosyl-2,5-dihydro-1H-pyrrol-2-yl acetate showed inhibitory action with Ki values in the range of 14.6-42.4 μM for hCA I and 0.53-37.5 μM for hCA II, respectively. All pyrrole derivatives were competitive inhibitors with 4-nitrophenylacetate as substrate. Some new synthesized pyrrole derivatives showed very effective hCA II inhibitory effects, in the same range as the clinically used sulfonamide acetazolamide, and might be used as leads for generating enzyme inhibitors targeting other CA isoforms.

Abdülkadir Coban, T.; Beydemir, Şükrü; Gücin, Ilhami; Ekinci, Deniz; Innocenti, Alessio; Vullo, Daniela; Supuran, Claudiu T.

Sildenafil citrate, a phosphodiesterase-5 (PDE5) inhibitor widely used for the treatment of erectile dysfunction was investigated for its interaction with the zinc-enzyme carbonic anhydrase (CA, EC 4.2.1.1), as it has in its molecule a piperazine moiety also found in some CA activators (CAAs). Sildenafil was a potent, low micromolar activator of several CA isozymes, such as CA I, VA and VI (KAs in the range of 1.08-6.54 μM), and activated slightly less the isoforms CA III, IV and VA (KAs of 13.4-16.8 μM). CA isozymes II, IX, XIII and XIV showed activation constants in the range of 27.5-34.0 μM, whereas the least activated isoforms were CA VII and XII (KAs of 72.9-73.0 μM). Sildenafil citrate was also given orally to Sprague-Dawley rats at 1 mg/kg body weight. Red blood cell CA activity was inhibited in the treated animals at 3-5 h post-administration (in the range of 60-85%), probably due to NO/nitrite formed by PDE5 inhibition or by another, unknown mechanism. Whether CA activation by sildenafil has clinical consequences in humans is beyond the scope of the present work and warrants further studies.