Exploring QSARs of some benzenesulfonamides incorporating cyanoacrylamide moieties as a carbonic anhydrase inhibitors (specifically against tumor-associated isoforms IX and XII)

Synthesis and Biological Evaluation of Cyanoacrylamides and 5-Iminopyrrol-2-Ones Against Naegleria fowleri

Primary amoebic meningoencephalitis is caused by the free-living amoeba Naegleria fowleri. The lack of standardized treatment has significantly contributed to the high fatality rates observed in reported cases. Therefore, this study aims to explore the anti-Naegleria activity of eight synthesized cyanoacrylamides and 5-iminopyrrol-2-ones. Notably, QOET-109, QOET-111, QOET-112, and QOET-114 exhibited a higher selectivity index against Naegleria compared to those of the rest of the compounds. Subsequently, these chemicals were assessed against the resistant stage of N. fowleri, demonstrating activity similar to that observed in the vegetative stage. Moreover, characteristic events of programmed cell death were evidenced, including chromatin condensation, increased plasma membrane permeability, mitochondrial damage, and heightened oxidative stress, among others. Finally, this research demonstrated the in vitro activity of the cyanoacrylamide and 5-iminopyrrol-2-one molecules, as well as the induction of metabolic event characteristics of regulated cell death in Naegleria fowleri.

QSAR modeling of pyrazoline derivative as carbonic anhydrase inhibitors

The efficacy of 34 pyrazoline derivatives as carbonic anhydrase inhibitors was studied in silico. The quantum descriptors were calculated by the DFT/B3LYP method using the 6-31G(d) basis; the dataset was randomly divided into training and testing. By altering the compounds in the sets, four models were created, and they were then used to determine the predicted pIC50 values for the six chemicals in the test set. According to the OECD guidelines for QSAR model validation and the Golbraikh and Tropsha's criteria for model approval, each created model was independently validated both internally and externally, along with YRandomization. Model 3 is chosen because it has higher R₂, R_2test, and Q_2cv values (R₂ = 0.79, R²_test = 0.95, Q²_cv = 0.64). Only one descriptor has a proportional influence on pIC50 activity, but the other four descriptors have an inverse influence on pIC50 because of the negative contribution coefficient. Given the descriptors of the model, we could propose new molecules with remarkable inhibitory activity.

Synthesis and Biological Evaluation of Imidazo[2 ,1-b]Thiazole based Sulfonyl Piperazines as Novel Carbonic Anhydrase II Inhibitors

A novel series of imidazo[2,1-b]thiazole-sulfonyl piperazine conjugates (9aa-ee) has been synthesized and evaluated for carbonic anhydrase (CA, EC 4.2.1.1) inhibitory potency against four isoforms: The cytosolic isozyme hCA I, II and trans-membrane tumor-associated isoform hCA IX and hCA XII, taking acetazolamide (AAZ) as standard drug, using a stopped flow CO₂ hydrase assay. The results revealed that most of the compounds showed selective activity against hCA II whereas none of them were active against hCA I, IX, XII (K_i > 100 µM). The physiologically dominant cytosolic isoform hCA II was inhibited by these molecules with inhibition constants in the range of 57.7–98.2 µM. This new derivative, thus, selectively inhibits hCA II over the hCA I, IX, XII isoforms, which may be used for further understanding the physiological roles of some of these isoforms in various pathologies.

Synthesis and biological evaluation of coumarin-1,3,4-oxadiazole hybrids as selective carbonic anhydrase IX and XII inhibitors

With an aim to develop novel heterocyclic hybrids as potent anticancer agents, we synthesized a series of coumarin-1,3,4-oxadiazole hybrids (7a-t) and evaluated for their inhibitory activity against the four physiologically relevant human carbonic anhydrase (hCA, EC 4.2.1.1) isoforms CA I, CA II, CA IX and CA XII. The CA inhibition results clearly indicated that the coumarin-1,3,4-oxadiazole derivatives (7a-t) exhibited selective inhibition of the tumor associated isoforms, CA IX and CA XII over CA I and II isoforms. Among all, compound 7b, exhibited significant inhibition in lower micromolar potency against hCA XII, with a K_i of 0.16 µM and compound 7n, exhibited significant inhibition in lower micromolar potency against hCA IX, with a K_i of 2.34 µM respectively. Therefore, compound 7b and 7n could be the potential leads for development of selective anticancer agents by exhibiting a novel mechanism of action through hCA IX and XII inhibition.

Design, synthesis and biological evaluation of coumarin-3-carboxamides as selective carbonic anhydrase IX and XII inhibitors

A series of novel 7-hydroxycoumarin-3-carboxamides was synthesized by the reaction of 7-hydroxy-2-oxo-2H-chromene-3-carboxylic acid with various substituted aromatic amines. The newly synthesized compounds were evaluated for their inhibitory activity against the four physiologically relevant human carbonic anhydrase (hCA, EC 4.2.1.1) isoforms CA I, CA II, CA IX and CA XII. The CA inhibition results show that the newly synthesized 7-hydroxycoumarin-3-carboxamides (4a-n) exhibited selective inhibition of the tumor associated isoforms, CA IX and CA XII over CA I and II isoforms. The inhibition constants ranged from sub micromolar to low micromolar. Amongst all the compounds tested, compound 4m was the most effective inhibitor exhibiting sub micromolar potency against both hCA IX and hCA XII, with a K_i of 0.2 µM. Therefore, it can be anticipated that compound 4m can serve as a lead for development of anticancer therapy by exhibiting a novel mechanism of action. The binding modes of the most potent compounds within hCA IX and XII catalytic clefts were investigated by docking studies.

Synthesis of N-alkyl (aril)-tetra pyrimidine thiones and investigation of their human carbonic anhydrase I and II inhibitory effects

Tetrahydropyrimidine thiones, which are cyclic thiocarbamides derivatives, were synthesised from thiourea, β-diketones and substituted benzaldehydes. A tautomeric form of these derivatives incorporates the thiol functionality, which is known to interact with metal ions from metalloenzymes active sites, such as the carbonic anhydrases (CAs, EC 4.2.1.1) among others. This is a superfamily of widespread enzymes, which catalyses a crucial biochemical reaction, the reversible hydration of carbon dioxide to bicarbonate and protons (H(+)). The newly synthesised N-alkyl (aril)-tetrahydropyrimidine thiones were tested for inhibition of the cytosolic human isoforms I and II (hCA I and II). Both isoforms were effectively inhibited by the newly synthesised thiones. Ki values were in the range of 218.5 ± 23.9-261.0 ± 41.5 pM for hCA I, and of 181.8 ± 41.9-273.6 ± 41.4 pM for hCA II, respectively. This under-investigated class of derivatives may bring interesting insights in the field of non-sulphonamide CA inhibitors.