New anthranilic acid-incorporating N-benzenesulfonamidophthalimides as potent inhibitors of carbonic anhydrases I, II, IX, and XII: Synthesis, in vitro testing, and in silico assessment

Uncovering Novel Capsaicin Inhibitory Activity towards Human Carbonic Anhydrase Isoforms IX and XII by Combining In Silico and In Vitro Studies

Hot pepper (Capsicum annuum) represents one of the most widespread functional foods of the Mediterranean diet, and is associated with a reduced risk of developing cardiovascular disease, cancer, and mental disorders. In particular, its bioactive spicy molecules, named Capsaicinoids, exhibit polypharmacological properties. Among them, Capsaicin (trans-8-methyl-N-vanillyl-6-nonenamide) is the most studied and reported in variegated scientific contributions for its beneficial effects, often linked to mechanisms of action unrelated to the activation of Transient Receptor Potential Vanilloid 1 (TRPV1). In this study, we present the application of in silico methods to Capsaicin for evaluating its inhibitory activity against the tumor-associated human (h) expressed CA IX and XII. In vitro assays confirmed Capsaicin inhibitory activity towards the most relevant tumor-related hCA isoforms. In particular, the hCAs IX and XII showed an experimental K_I value of 0.28 μM and 0.064 μM, respectively. Then, an A549 model of non-small cell lung cancer, typically characterized by an elevated expression of hCA IX and XII, was employed to test the inhibitory effects of Capsaicin in vitro under both normoxic and hypoxic conditions. Finally, the migration assay revealed that Capsaicin [10 µM] inhibits cells from moving in the A549 cells model.

In Combo Studies for the Optimization of 5-Aminoanthranilic Acid Derivatives as Potential Multitarget Drugs for the Management of Metabolic Syndrome

Metabolic syndrome is a set of risk factors that consist of abdominal obesity, arterial hypertension, alterations in the lipid profile, and hyperglycemia. The current therapeutic strategy includes polypharmacy, using three or more drugs to control each syndrome component. However, this approach has drawbacks that could lead to therapeutic failure. Multitarget drugs are molecules with the ability to act on different targets simultaneously and are an attractive alternative for treating complex diseases such as metabolic syndrome. Previously, we identified a triamide derivative of 5-aminoanthranilic acid that exhibited hypoglycemic, hypolipemic, and antihypertensive activities simultaneously. In the present study, we report the synthesis and in combo evaluation of new derivatives of anthranilic acid, intending to identify the primary structural factors that improve the activity over metabolic syndrome-related parameters. We found that substitution on position 5, incorporation of 3,4-dimethoxyphenyl substituents, and having a free carboxylic acid group lead to the in vitro inhibition of HMG-CoA reductase, and simultaneously the diminution of the serum levels of glucose, triglycerides, and cholesterol in a diet-induced in vivo model.

Carbonic Anhydrase Inhibition Activities of Schiff's Bases Based on Quinazoline-Linked Benzenesulfonamide

Human carbonic anhydrase (CA, EC 4.2.1.1) (hCA) isoforms I, II, IX, and XII were investigated for their inhibitory activity with a series of new Schiff's bases based on quinazoline scaffold 4-27. The hCA I isoform was efficiently inhibited by Schiff's bases 4-6, 10-19, 22-27 and had an inhibition constant (Ki) value of 52.8-991.7 nM compared with AAZ (Ki, 250 nM). Amongst the quinazoline derivatives, the compounds 2, 3, 4, 10, 11, 16, 18, 24, 26, and 27 were proven to be effective hCA II inhibitors, with Ki values of 10.8-52.6 nM, measuring up to AAZ (Ki, 12 nM). Compounds 2-27 revealed compelling hCA IX inhibitory interest with Ki values of 10.5-99.6 nM, rivaling AAZ (Ki, 25.0 nM). Quinazoline derivatives 3, 10, 11, 13, 15-19, and 24 possessed potent hCA XII inhibitory activities with K_I values of 5.4-25.5 nM vs. 5.7 nM of AAZ. Schiff's bases 7, 8, 9, and 21 represented attractive antitumor hCA IX carbonic anhydrase inhibitors (CAIs) with K_I rates (22.0, 34.8, 49.2, and 45.3 nM, respectively). Compounds 5, 7, 8, 9, 14, 18, 19, and 21 showed hCA I inhibitors on hCA IX with a selectivity index of 22.46-107, while derivatives 12, 14, and 18 showed selective hCA I inhibitors on hCA XII with a selectivity profile of 45.04-58.58, in contrast to AAZ (SI, 10.0 and 43.86). Compounds 2, 5, 7-14, 19-23, and 25 showed a selectivity profile for hCA II inhibitors over hCA IX with a selectivity index of 2.02-19.67, whereas derivatives 5, 7, 8, 13, 14, 15, 17, 20, 21, and 22 showed selective hCA II inhibitors on hCA XII with a selectivity profile of 4.84-26.60 balanced to AAZ (SI, 0.48 and 2.10).

In Silico-Based Design and In Vivo Evaluation of an Anthranilic Acid Derivative as a Multitarget Drug in a Diet-Induced Metabolic Syndrome Model

Metabolic syndrome (MetS) is a complex disease that affects almost a quarter of the world's adult population. In MetS, diabetes, obesity, hyperglycemia, high cholesterol, and high blood pressure are the most common disorders. Polypharmacy is the most used strategy for managing conditions related to MetS, but it has drawbacks such as low medication adherence. Multitarget ligands have been proposed as an interesting approach to developing drugs to treat complex diseases. However, suitable preclinical models that allow their evaluation in a context closer to a clinical situation of a complex disease are needed. From molecular docking studies, compound 1b, a 5-aminoanthranilic acid derivative substituted with 4'-trifluoromethylbenzylamino and 3',4'-dimethoxybenzamide moieties, was identified as a potential multitarget drug, as it showed high in silico affinity against targets related to MetS, including PPAR-α, PPAR-γ, and HMG-CoA reductase. It was evaluated in a diet-induced MetS rat model and simultaneously lowered blood pressure, glucose, total cholesterol, and triglyceride levels after a 14-day treatment. No toxicity events were observed during an acute lethal dose evaluation test at 1500 mg/kg. Hence, the diet-induced MetS model is suitable for evaluating treatments for MetS, and compound 1b is an attractive starting point for developing multitarget drugs.

Remarkable Conversion of 2-Thioxo-2,3-dihydroquinazolin-4(1H)-ones into the Corresponding Quinazoline-2,4(1H,3H)-diones: Spectroscopic Analysis and X-Ray Crystallography

A simple and efficient new synthetic method to obtain 3-substituted quinazolin-2,4-diones 9–16 by the reaction of 3-substituted 2-thioxo-quinazolin-4-ones 1–8 with sodamide under mild conditions was presented. The structure of the newly synthesized compounds was determined by infrared spectroscopy, UV-visible spectroscopy, nuclear magnetic resonance, and single-crystal X-ray crystallographic analysis. The crystal structure of 6-methyl-3-phenylquinazoline-2,4(1H,3H)-dione (11) [C15H12N2O2: MF = 252.27, triclinic, P-1, a = 7.8495 (13) Å, b = 12.456 (2) Å, c = 13.350 (2) Å, α = 103.322 (3)°, β = 90.002 (3)°, γ = 102.671 (4)°, V = 1237.5 (3) Å3, Z = 4, R = 0.0592, wR = 0.1699, S = 1.039] was determined. In the crystal cell, two identical conformers of compound 11 were found connected by intramolecular hydrogen bonds, responsible for the favourable occurrence of these two independent molecules.

Synthesis, anti-inflammatory, cytotoxic, and COX-1/2 inhibitory activities of cyclic imides bearing 3-benzenesulfonamide, oxime, and β-phenylalanine scaffolds: a molecular docking study

Cyclic imides containing 3-benzenesulfonamide, oxime, and β-phenylalanine derivatives were synthesised and evaluated to elucidate their in vivo anti-inflammatory and ulcerogenic activity and in vitro cytotoxic effects. Most active anti-inflammatory agents were subjected to in vitro COX-1/2 inhibition assay. 3-Benzenesulfonamides (2-4, and 9), oximes (11-13), and β-phenylalanine derivative (18) showed potential anti-inflammatory activities with 71.2-82.9% oedema inhibition relative to celecoxib and diclofenac (85.6 and 83.4%, respectively). Most active cyclic imides 4, 9, 12, 13, and 18 possessed ED50 of 35.4-45.3 mg kg-1 relative to that of celecoxib (34.1 mg kg-1). For the cytotoxic evaluation, the selected derivatives 2-6 and 8 exhibited weak positive cytotoxic effects (PCE = 2/59-5/59) at 10 μM compared to the standard drug, imatinib (PCE = 20/59). Cyclic imides bearing 3-benzenesulfonamide (2-5, and 9), acetophenone oxime (11-14, 18, and 19) exhibited high selectivity against COX-2 with SI > 55.6-333.3 relative to that for celecoxib [SI > 387.6]. β-Phenylalanine derivatives 21-24 and 28 were non-selective towards COX-1/2 isozymes as indicated by their SI of 0.46-0.68.

S-substituted 2-mercaptoquinazolin-4(3H)-one and 4-ethylbenzensulfonamides act as potent and selective human carbonic anhydrase IX and XII inhibitors

We evaluated the hCA (CA, EC 4.2.1.1) inhibitory activity of novel 4-(2-(2-substituted-thio-4-oxoquinazolin-3(4H)-yl)ethyl)benzenesulfonamides (compounds 2–20) towards the isoforms I, II, IX, and XII. hCA Isoforms were effectively inhibited by most of new compounds comparable to those of AAZ. Compounds 2 and 4 showed interestingly efficient and selective antitumor (hCA IX and hCA XII) inhibitor activities (K_Is; 40.7, 13.0, and 8.0, 10.8 nM, respectively). Compounds 4 and 5 showed selective hCA IX inhibitory activity over hCA I (SI; 95 and 24), hCA IX/hCA II (SI; 23 and 5.8) and selective hCA XII inhibitory activity over hCA I (SI; 70 and 44), hCA XII/hCA II, (SI; 17 and 10) respectively compared to AAZ. Compounds 12–17, and 19–20 showed selective inhibitory activity towards hCA IX over hCA I and hCA II, with selectivity ranges of 27–195 and 3.2–19, respectively, while compounds 12, 14–17, and 19 exhibited selective inhibition towards hCA XII over hCA I and hCA II, with selectivity ratios of 48–158 and 5.4–31 respectively, compared to AAZ. Molecular docking analysis was carried out to investigate the selective interactions among the most active derivatives, 17 and 20 and hCAs isoenzymes. Compounds 17 and 20, which are highly selective CA IX and XII inhibitors, exhibited excellent interaction within the putative binding site of both enzymes, comparable to the co-crystallized inhibitors.

Highlights

Quinazoline-linked ethylbenzenesulfonamides inhibiting CA were synthesised.

The new molecules potently inhibited the hCA isoforms I, II, IV, and IX.

Compounds 4 and 5 were found to be selective hCA IX/hCA I and hCA IX/hCA II inhibitors.

Compounds 4 and 5 were found to be selective hCA XII/hCA I and hCA XII/hCA II inhibitors.

Compounds 12–17, 19, and 20 were found to be selective hCA IX/hCA I and hCA IX/hCA II inhibitors.

Compounds 12, 14–17, 19 were found to be selective hCA XII/hCA I and hCA XII/hCA II inhibitors.

Graphical Abstract

Compounds 4 and 5 are selective hCA IX and XII inhibitors over hCA I (selectivity ratios of 95, 23, and 24, 5.8, respectively) and hCA II (selectivity ratios of 70, 17, and 44, 10 respectively). Compounds 12–17, and 19–20 are selective hCA IX inhibitors over hCA I (selectivity ratios of 27-195) and hCA II (selectivity ratios of 3.2-19). Compounds 12, 14–17 and 19 are also selective hCA XII inhibitors over hCA I (selectivity ratios of 48-158) and hCA II (selectivity ratios of 5.4-31).

Exploring structure-activity relationship of S-substituted 2-mercaptoquinazolin-4(3H)-one including 4-ethylbenzenesulfonamides as human carbonic anhydrase inhibitors

Inhibitory action of newly synthesised 4-(2-(2-substituted-thio-4-oxoquinazolin-3(4H)-yl)ethyl)benzenesulfonamides compounds 2-13 against human carbonic anhydrase (CA, EC 4.2.1.1) (hCA) isoforms I, II, IX, and XII, was evaluated. hCA I was efficiently inhibited by compounds 2-13 with inhibition constants (K_Is) ranging from 57.8-740.2 nM. Compounds 2, 3, 4, and 12 showed inhibitory action against hCA II with K_Is between 6.4 and 14.2 nM. CA IX exhibited significant sensitivity to inhibition by derivatives 2-13 with K_I values ranging from 7.1 to 93.6 nM. Compounds 2, 3, 4, 8, 9, and 12 also exerted potent inhibitory action against hCA XII (K_Is ranging from 3.1 to 20.2 nM). Molecular docking studies for the most potent compounds 2 and 3 were conducted to exhibit the binding mode towards hCA isoforms as a promising step for SAR analyses which showed similar interaction with co-crystallized ligands. As such, a subset of these mercaptoquinazolin-4(3H)-one compounds represented interesting leads for developing new efficient and selective carbonic anhydrase inhibitors (CAIs) for the management of a variety of diseases including glaucoma, epilepsy, arthritis and cancer.

Native mass spectrometry of human carbonic anhydrase I and its inhibitor complexes

Abstract

Native mass spectrometry is a potent technique to study and characterize biomacromolecules in their native state. Here, we have applied this method to explore the solution chemistry of human carbonic anhydrase I (hCA I) and its interactions with four different inhibitors, namely three sulfonamide inhibitors (AAZ, MZA, SLC-0111) and the dithiocarbamate derivative of morpholine (DTC). Through high-resolution ESI-Q-TOF measurements, the native state of hCA I and the binding of the above inhibitors were characterized in the molecular detail. Native mass spectrometry was also exploited to assess the direct competition in solution among the various inhibitors in relation to their affinity constants. Additional studies were conducted on the interaction of hCA I with the metallodrug auranofin, under various solution and instrumental conditions. Auranofin is a selective reagent for solvent-accessible free cysteine residues, and its reactivity was analyzed also in the presence of CA inhibitors. Overall, our investigation reveals that native mass spectrometry represents an excellent tool to characterize the solution behavior of carbonic anhydrase.

Graphic abstract

Electronic supplementary material

The online version of this article (10.1007/s00775-020-01818-8) contains supplementary material, which is available to authorized users.

Design, synthesis, and antitumor activity of novel compounds based on 1,2,4-triazolophthalazine scaffold: Apoptosis-inductive and PCAF-inhibitory effects

The antitumor activity of newly synthesised triazolophthalazines (L-45 analogues) 10-32 was evaluated in human hepatocellular carcinoma (HePG-2), breast cancer (MCF-7), prostate cancer (PC3), and colorectal carcinoma (HCT-116) cells. Compounds 17, 18, 25, and 32 showed potent antitumor activity (IC₅₀, 2.83-13.97 μM), similar to doxorubicin (IC₅₀, 4.17-8.87 μM) and afatinib (IC₅₀, 5.4-11.4 μM). HePG2 was inhibited by compounds 10, 17, 18, 25, 26, and 32 (IC₅₀, 3.06-10.5 μM), similar to doxorubicin (IC₅₀, 4.50 μM) and afatinib (IC₅₀, 5.4 μM). HCT-116 and MCF-7 were susceptible to compounds 10, 17, 18, 25, and 32 (IC₅₀, 2.83-10.36 and 5.69-11.36 μM, respectively), similar to doxorubicin and afatinib (IC₅₀ = 5.23 and 4.17, and 11.4 and 7.1 μM, respectively). Compounds 17, 25, and 32 exerted potent activities against PC3 (IC₅₀, 7.56-12.28 μM) compared with doxorubicin (IC₅₀, 8.87 µM) and afatinib (IC₅₀ 7.7 μM). Compounds 17 and 32 were the strongest PCAF inhibitors (IC₅₀, 5.31 and 10.30 μM, respectively) and compounds 18 and 25 exhibited modest IC₅₀ values (17.09 and 32.96 μM, respectively) compared with bromosporine (IC₅₀, 5.00 μM). Compound 17 was cytotoxic to HePG2 cells (IC₅₀, 3.06 μM), inducing apoptosis in the pre-G phase and arresting the cell cycle in the G2/M phase. Molecular docking for the most active PCAF inhibitors (17 and 32) was performed.

Synthetic Strategies and Computational Inhibition Activity Study for Triazinyl-Substituted Benzenesulfonamide Conjugates with Polar and Hydrophobic Amino Acids as Inhibitors of Carbonic Anhydrases

Various sulfonamide derivatives are intensively studied as anticancer agents owing to their inhibitory activity against human tumor-associated carbonic anhydrase isoforms. In this work, different synthetic procedures for the series of 1,3,5-triazinyl-aminobenzenesulfonamide conjugates with amino acids, possessing polar uncharged, negatively charged, and hydrophobic side chain, were studied and optimized with respect to the yield/purity of the synthesis/product as well as the time of synthetic reaction. These procedures were compared to each other via characteristic HPLC-ESI-DAD/QTOF/MS analytical product profiles, and their benefits as well as limitations were discussed. For new sulfonamide derivatives, incorporating s-triazine with a symmetric pair of polar and some less-polar proteinogenic amino acids, inhibition constants (KIs) against four human carboanhydrases (hCAs), namely cytosolic hCA I, II, transmembrane hCA IV, and the tumor-associated, membrane-bound hCA IX isoforms, were computationally predicted applying various methods of the advanced statistical analysis. Quantitative structure-activity relationship (QSAR) analysis indicated an impressive KI ratio (hCA II/hCA IX) 139.1 and hCA IX inhibition constant very similar to acetazolamide (KI = 29.6 nM) for the sulfonamide derivative disubstituted with Gln. The derivatives disubstituted with Ser, Thr, and Ala showed even lower KIs (8.7, 13.1, and 8.4 nM, respectively).

Discovery of the first Mycobacterium tuberculosis MabA (FabG1) inhibitors through a fragment-based screening

Mycobacterium tuberculosis (M.tb), the etiologic agent of tuberculosis, remains the leading cause of death from a single infectious agent worldwide. The emergence of drug-resistant M.tb strains stresses the need for drugs acting on new targets. Mycolic acids are very long chain fatty acids playing an essential role in the architecture and permeability of the mycobacterial cell wall. Their biosynthesis involves two fatty acid synthase (FAS) systems. Among the four enzymes (MabA, HadAB/BC, InhA and KasA/B) of the FAS-II cycle, MabA (FabG1) remains the only one for which specific inhibitors have not been reported yet. The development of a new LC-MS/MS based enzymatic assay allowed the screening of a 1280 fragment-library and led to the discovery of the first small molecules that inhibit MabA activity. A fragment from the anthranilic acid series was optimized into more potent inhibitors and their binding to MabA was confirmed by ¹⁹F ligand-observed NMR experiments.

Novel functionally substituted esters based on sodium diethyldithiocarbamate derivatives: Synthesis, characterization, biological activity and molecular docking studies

Alkylation of sodium diethyldithiocarbamate with allyl-2-chloroacetate, allyl-3-chloropropionate, chloromethyl-2-(tetrahydrofuran-2-yl)acetate, and 4-(chloromethyl)-1,3-dioxolane in the aqueous medium synthesized functionally substituted esters of N, N-dietyleditiocarbamic acid (M1-M4). Most active compounds were docked into the catalytic active site of the enzyme. We identified that acetate moiety for inhibition of hCA I, hCA II, and α-glycosidase and dioxolane and thiocarbamic acid moieties for inhibition of AChE and BChE enzymes are very important. The hCA I isoform was inhibited by these novel functionally substituted esters based on sodium diethyldithiocarbamate derivatives (M1-M4) in low micromolar levels, the Ki of which differed between 48.03 ± 9.77 and 188.42 ± 46.08 µM. Against the physiologically dominant isoform hCA II, the novel compounds demonstrated K_is varying from 57.33 ± 6.21 to 174.34 ± 40.72 µM. Also, these novel derivatives (M1-M4) effectively inhibited AChE, with Ki values in the range of 115.42 ± 12.44 to 243.22 ± 43.65 µM. For BChE Ki values were found in the range of 94.33 ± 9.14 to 189.45 ± 35.88 µM. For α-glycosidase the most effective Ki values of M4 and M3 were with Ki values of 32.86 ± 7.88 and 37.63 ± 4.08 µM, respectively.