Secondary Sulfonamides as Effective Lactoperoxidase Inhibitors

Screening of in Vitro Inhibition of Lactoperoxidase Enzyme by Methyl Benzoate Derivatives with Molecular Docking Studies

Lactoperoxidase enzyme (LPO) is secreted from salivary, mammary, and other mucosal glands including the bronchi, lungs, and nose, which had functions as a natural and the first line of defense towards viruses and bacteria. In this study, methyl benzoates were examined in LPO enzyme activity. Methyl benzoates are used as precursors in the synthesis of aminobenzohydrazides used as LPO inhibitors. For this purpose, LPO was purified in a single step using sepharose-4B-l-tyrosine-sulfanilamide affinity gel chromatography with a yield of 9.91 % from cow milk. Also, some inhibition parameters including the half maximal inhibitory concentration (IC50 ) value and an inhibition constant (Ki ) values of methyl benzoates were determined. These compounds inhibited LPO with Ki values ranging from 0.033±0.004 to 1540.011±460.020 μM. Compound 1 a (methyl 2-amino-3-bromobenzoate) showed the best inhibition (Ki =0.033±0.004 μM). The most potent inhibitor (1 a) showed with a docking score of -3.36 kcal/mol and an MM-GBSA value of -25.05 kcal/mol, of these methyl benzoate derivatives (1 a-16 a) series are established H-bond within the binding cavity with residues Asp108 (distance of 1.79 Å), Ala114 (distance of 2.64 Å), and His351 (distance of 2.12 Å).

Some sulfonamides as aldose reductase inhibitors: therapeutic approach in diabetes

In this study, aldose reductase (AR) was purified from sheep kidney using chromatographic methods and examined the interactions between some sulfonamides and the enzyme. According to results, sulfonamides display effective inhibitor features for sheep kidney AR with IC₅₀ values in the range of 37.27-87.65 μM and K_is in the range of 25.72 ± 6.45 to 73.56 ± 17.49 μM. The sulfonamides displayed different inhibition mechanisms. It was found that studied all compounds displayed non-competitive inhibition type except for 5-chlorothiophene-2-sulfonamide (1). It showed competitive inhibition. Among these compounds, 2,5-dichlorothiophene-3-sulfonamide compound (2) was showed the most potent AR inhibitor (K_i: 25.72 ± 6.45). These compounds may be useful in the treatment of diabetic complications.

Phosphine/Photoredox Catalyzed Anti-Markovnikov Hydroamination of Olefins with Primary Sulfonamides via α-Scission from Phosphoranyl Radicals

New strategies to access radicals from common feedstock chemicals hold the potential to broadly impact synthetic chemistry. We report a dual phosphine and photoredox catalytic system that enables direct formation of sulfonamidyl radicals from primary sulfonamides. Mechanistic investigations support that the N-centered radical is generated via α-scission of the P-N bond of a phosphoranyl radical intermediate, formed by sulfonamide nucleophilic addition to a phosphine radical cation. As compared to the recently well-explored β-scission chemistry of phosphoranyl radicals, this strategy is applicable to activation of N-based nucleophiles and is catalytic in phosphine. We highlight application of this activation strategy to an intermolecular anti-Markovnikov hydroamination of unactivated olefins with primary sulfonamides. A range of structurally diverse secondary sulfonamides can be prepared in good to excellent yields under mild conditions.

A novel sulfamethoxazole derivative as an inhibitory agent against HSP70: A combination of computational with in vitro studies

In the current study, a novel derivative of sulfamethoxazole (a sulfonamide containing anti-biotic) named ZM-093 (IUPAC name: (E)-4-((4-(bis(2-hydroxyethyl)amino)phenyl)diazenyl)-N-(5-methylisoxazole-3-yl)benzenesulfonamide) was synthesized via common diazotization-coupling reactions from sulfamethoxazole and subsequently characterized through NMR/FT-IR spectroscopy. After evaluation, the compound was geometrically optimized at the DFT level of theory with BL3YP method and 6/31++G (d,p) basis set and from the optimized structure, several molecular descriptors important in the biological reactivity of the compound, such as global reactivity parameters, molecular electrostatic potential, average local ionization energy, and drug-likeness features of the compound were computationally analyzed. The experimental in vitro investigations of the interaction between ZM-093 and heat shock protein 70 (HSP70), a protein that is highly expressed in several types of cancers, exhibited a significant inhibitory effect against the chaperone activity of HSP70 for the titled compound (P-value < 0.01) and the comparison between the experimental studies with the mentioned computational analysis, as well as molecular docking, illustrated that ZM-093 may inhibit HSP70 through binding to its substrate-binding domain. Finally, by taking all the previous results into account, a new method for assessing the inhibitory activity of ligand to HSP70 is introduced based on protonography, a recently developed method that is dependent on the catalytic activity of carbonic anhydrase on polyacrylamide gel electrophoresis.

Coumarins and Gastrointestinal Cancer: A New Therapeutic Option?

Cancers of the gastrointestinal (GI) tract are often life-threatening malignancies, which can be a severe burden to the health care system. Globally, the mortality rate from gastrointestinal tumors has been increasing due to the lack of adequate diagnostic, prognostic, and therapeutic measures to combat these tumors. Coumarin is a natural product with remarkable antitumor activity, and it is widely found in various natural plant sources. Researchers have explored coumarin and its related derivatives to investigate their antitumor activity, and the potential molecular mechanisms involved. These mechanisms include hormone antagonists, alkylating agents, inhibitors of angiogenesis, inhibitors of topoisomerase, inducers of apoptosis, agents with antimitotic activity, telomerase inhibitors, inhibitors of human carbonic anhydrase, as well as other potential mechanisms. Consequently, drug design and discovery scientists and medicinal chemists have collaborated to identify new coumarin-related agents in order to produce more effective antitumor drugs against GI cancers. Herein, we summarize the therapeutic effects of coumarin and its derivatives against GI cancer.

Cholinesterases, carbonic anhydrase inhibitory properties and in silico studies of novel substituted benzylamines derived from dihydrochalcones

A series of novel urea, sulfamide and N,N-dipropargyl substituted benzylamines were synthesized from dihydrochalcones. The synthesized compounds were evaluated for their cholinesterases and carbonic anhydrase inhibitory actions. The known dihydrochalcones were converted into four new benzylamines via reductive amination. N,N-Dipropargylamines, ureas and sulfamides were synthesized following the reactions of benzylamines with propargyl bromide, N,N-dimethyl sulfamoyl chloride and N,N-dimethyl carbamoyl chloride. The novel substituted benzylamines derived from dihydrochalcones were evaluated against some enzymes such as human erythrocyte carbonic anhydrase I and II isoenzymes (hCA I and hCA II), acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). The novel substituted benzylamines derived from dihydrochalcones exhibited K_i values in the range of 0.121-1.007 nM on hCA I, and 0.077-0.487 nM on hCA II closely related to several pathological processes. On the other hand, K_i values were found in the range of 0.112-0.558 nM on AChE, 0.061-0.388 nM on BChE. As a result, novel substituted benzylamines derived from dihydrochalcones showed potent inhibitory profiles against indicated metabolic enzymes. In addition, Induced-Fit Docking (IFD) simulations and ADME prediction studies have also been carried out to elucidate the inhibition mechanisms and drug-likeness of the synthesized compounds. Therefore, these results can make significant contributions to the treatment of some global diseases, especially Alzheimer's diseases and glaucoma, and the development of new drugs.

Pyrrolo and pyrrolopyrimidine sulfonamides act as cytotoxic agents in hypoxia via inhibition of transmembrane carbonic anhydrases

A series of novel sulfonamide derivatives bearing pyrrole and pyrrolopyrimidine scaffolds were synthesized and screened as carbonic anhydrase inhibitors. The inhibition activity of the synthesized compounds was evaluated against the cytosolic human carbonic anhydrase isoforms I and II and the transmembranal isoforms IX and XII. Several candidates showed potent inhibitory activity against IX and XII isoforms. Furthermore, ex vivo screening of cytotoxic selectivity and activity of the most potent derivatives were carried out against normal cells (WI38) and cervical cancer cell line (HeLa) under normal and hypoxic conditions using acetazolamide as reference drug. Compound 11b potency was nearly three folds higher in hypoxic than normoxic condition whereas that of compound 11f was nearly four folds higher in hypoxic vs. normoxic HeLa cells. All the screened derivatives exhibited less potency on normal cells (WI38). Molecular docking was carried out to discover the possible binding mode of compounds within the active site of isoform CA IX.

Lactoperoxidase inhibition of some natural phenolic compounds: Kinetics and molecular docking studies

The inhibition effects of some phenolic compounds from natural products such as taxifolin, resveratrol, olivetol, cynarine, and phloretin on bovine milk lactoperoxidase (LPO) enzyme were examined. For this aim, LPO was purified by the affinity chromatography technique with a yield of 77.68% in 421.32 times. The kinetic value, K_i , was calculated from the equations obtained from drawn graphs. In order to discover inhibition mechanism of phenolic compounds, induced fit docking process was performed on the LPO receptors. The binding affinity of the compounds was calculated and at the best-scored ligand-receptor complex, residues responsible for enzyme inhibition were detected. As a result, this molecule demonstrated the potential inhibitory effect on LPO. According to the results of kinetic study. It has shown a noncompetitive inhibition effect, Phloretin's K_i value was determined by 48.89 ± 14.22 nM. PRACTICAL APPLICATIONS: There are natural antimicrobial systems, such as the lactoperoxidase (E.C.1.11.1.7; LPO) system, which eliminates the harmful effects of microorganisms in milk. The chemical reactions in this system are catalyzed by the LPO. In the dairy industry, the LPO system is considered critical for the preservation of pasteurized milk, yogurt, raw milk, and cheese. The system is used for improvement the protection condition of milk at high temperatures.

Synthesis of coumarin-sulfonamide derivatives and determination of their cytotoxicity, carbonic anhydrase inhibitory and molecular docking studies

Carbonic anhydrases isoforms CA IX, and XII are known to be highly expressed in various human tissues and malignancies. CA IX is a prominent target for especially colorectal cancers, because it is overexpressed in colorectal cancer and this overexpression leads poor prognosis. Inhibition of CA IX activity by small molecule CA inhibitors like sulfonamides, sulfonamide derivative or coumarins leads to inhibition of tumorigenesis. Novel twenty-seven compounds in three series (sulfonamide-based imines (6a-6i), coumarin-based aldehydes (7a-7i), and coumarin-sulfonamide-based target molecules (8a-8i)) were synthesized and characterized by means of IR, NMR, and mass spectra. All compounds were tested for their ability to inhibit CA I, CA II, CA IX, and CA XII isoforms. 4-((((2-((1-(3-((2-oxo-2H-chromen-7-yl)oxy)propyl)-1H-1,2,3-triazol-4-yl)methoxy)naphthalen-1-yl)-methylene)amino)methyl)benzenesulfonamide (8i) exhibited the highest hCA IX inhibition with the Ki of 45.5 nM. In addition, 8i was found to be potent in inhibiting cancer cell proliferation as selective (IC₅₀ = 17.01 ± 1.35 μM for HT-29, IC₅₀ = 118.73 ± 1.19 μM for HEK293T). This novel compound inhibited the CA IX and CA XII protein expression in HT-29 cells. These findings indicate that 8i can inhibit cellular proliferation in human colon cancer cells by specifically targeting the CA IX and CA XII expression.

Synthesis, biological evaluation and in silico studies of novel N-substituted phthalazine sulfonamide compounds as potent carbonic anhydrase and acetylcholinesterase inhibitors

The synthesis, characterization and biological evaluation of a series of novel N-substituted phthalazine sulfonamide (5a-l) are disclosed. Phthalazines which are nitrogen-containing heterocyclic compounds are biologically preferential scaffolds, endowed with versatile pharmacological activity, such as anti-inflammatory, cardiotonic vasorelaxant, anticonvulsant, antihypertensive, antibacterial, anti-cancer action. The compounds were investigated for the inhibition against the cytosolic hCA I, II and AChE. Most screened sulfonamides showed high potency in inhibiting hCA II, widely involved in glaucoma, epilepsy, edema, and other pathologies (K_is in the ranging from 6.32 ± 0.06 to 128.93 ± 23.11 nM). hCA I was inhibited with K_is in the range of 6.80 ± 0.10-85.91 ± 7.57 nM, whereas AChE in the range of 60.79 ± 3.51-249.55 ± 7.89 nM. ADME prediction study of the designed N-substituted phthalazine sulfonamides showed that they are not only with carbonic anhydrase and acetylcholinesterase inhibitory activities but also with appropriate pharmacokinetic, physicochemical parameters and drug-likeness properties. Also, in silico docking studies were investigated the binding modes of selected compounds, to hCA I, II, and AChE.

Inhibition effects of selected thiophene-2-sulfonamides on lactoperoxidase

Lactoperoxidase (LPO, E.C.1.11.1.7) is a natural antibacterial agent which is secreted from salivary, mammary, and other mucosal glands. It is one of the crucial enzymes in biological systems, so protection of LPO activity is extremely important for the immune system. Within the scope of this study; in vitro effects of some thiophene-2-sulfonamide derivatives (1a-7a) on bovine milk LPO enzymatic activity were investigated. LPO was purified from the Sepharose-4B-L-tyrosine-5-amino-2-methylbenzenesulfonamide column prepared using affinity chromatography technique with a yield of 169.66 EU/mg specific activity in 452.44 times. As a result, 5-(2-thienylthio) thiophene-2-sulfonamide demonstrated the strongest inhibition impact among these compounds. This molecule has shown a competitive inhibition and it was determined that the IC₅₀ value was 3.4 nM and the Ki value was 2 ± 0.6 nM.

Lactoperoxidase, an antimicrobial enzyme, is inhibited by some indazoles

Lactoperoxidase (LPO) has bactericidal and bacteriostatic activity on various microorganisms and it creates a natural antimicrobial defense system. So, LPO is one of the essential enzyme in biological systems and the protection of the LPO activity is extremely important for the immune system. Because of these features, the protection of the activity of the LPO has vital importance for the health of the organisms. Also, LPO is used in various sectors from cosmetics industry to agriculture industry due to its broad antimicrobial properties. Therefore, the identification of inhibitors and activators of the LPO is becoming increasingly important. In present study we aimed to investigate the inhibitory effects of some indazoles [1H-indazole (1a), 4-Bromo-1H-indazole (2a), 6-Bromo-1H-indazole (3a), 7-Bromo-1H-indazole (4a), 4-chloro-1H-indazole (5a), 6-chloro-1H-indazole (6a), 7-chloro-1H-indazole (7a), 4-fluoro-1H-indazole (8a), 6-fluoro-1H-indazole (9a), 7-fluoro-1H-indazole (10a)] on bovine milk LPO. Indazole derivatives are heterocyclic organic molecules with a wide range of biological activity. For this aim, bovine milk LPO was purified using Sepharose-4B-l-tyrosine-5-amino-2-methyl benzenesulfonamide affinity chromatography method. Then, the potential inhibitory effects of indazoles on LPO activity were investigated. K_i values were calculated for each indazole molecule. K_i values were ranging from 4.10 to 252.78 µM for 1a to10a. All of the indazole molecules we studied showed strong inhibitory effect on LPO activity. Also we determined inhibition types of the indazoles to clarify the mechanisms of inhibition.

Novel thioureido-benzenesulfonamide derivatives with enaminone linker as potent anticancer, radiosensitizers and VEGFR2 inhibitors

In this study, novel series of thioureido-benzenesulfonamide derivatives bearing an enaminone linker either meta or para oriented and having terminal linear or substituted aromatic or heteroaromatic ring system 5-16a,b were designed and synthesized based on the general pharmacophoric features of type II VEGFR2 inhibitors. Evaluation of the synthesized compounds against HEPG2 hepatocellular carcinoma cells in vitro identified compounds 5b, 6b and 10-13b as most active anticancer agents with IC50 equal to 0.12, 0.29, 0.58, 0.44, 0.42 and 0.66 µM, respectively. These compounds were evaluated for their ability to in vitro inhibit VEGFR2 kinase enzyme. The results demonstrated highly potent dose-related VEGFR2 inhibition with IC50 values in nanomolar range (33, 57, 210, 37, 37 and 220 nM, respectively). The radiosensitizing ability of the most promising compounds was studied which showed an increase in the cell killing effect of radiation after combination with the synthesized compounds which revealed lowered IC50 by nearly 50%. Molecular docking for the most potent compounds was performed to predict their possible binding mode within VEGFR2 active site and they showed binding affinity in a similar way to sorafenib.

Synthesis of chalcone-imide derivatives and investigation of their anticancer and antimicrobial activities, carbonic anhydrase and acetylcholinesterase enzymes inhibition profiles

The new 1-(4-(3-(aryl)acryloyl)phenyl)-1H-pyrrole-2,5-diones (5a-g) were prepared from 4'-aminchalcones (3a-g) and screened for biological activities. All compounds (3a-g and 5a-g), except 3d and 3e displayed good cytotoxic activities with IC₅₀ values in the range of 7.06-67.46 μM. IC₅₀ value of 5-fluorouracil (5-FU) was 90.36 μM. Moreover, most of compounds 5a-g showed high antibacterial activity with 8-20 mm of inhibition zone (19-25 mm of Sulbactam-Cefoperazone (SCF)). In addition, they showed good inhibitory action against acetylcholinesterase (AChE), and human carbonic anhydrase I, and II (hCA I and hCA II) isoforms. Also, these compounds demonstrated effective inhibition profiles with Ki values of 426.47-699.58 nM against hCA I, 214.92-532.21 nM against hCA II, and 70.470-229.42 nM against AChE. On the other hand, acetazolamide, clinically used drug, showed a Ki value of 977.77 ± 227.4 nM against CA I, and 904.47 ± 106.3 nM against CA II, respectively. Also, tacrine inhibited AChE showed a Ki value of 446.56 ± 58.33 nM.

Special Issue: Sulfonamides

The sulfonamides and their structurally related derivatives, such as the sulfamates and sulfamides, possess the general formula A-SO2NHR, in which the functional group is either directly bound to an aromatic, heterocyclic, aliphatic, or sugar scaffold (of type A), or appended to such a scaffold via a heteroatom, most frequently oxygen or nitrogen (leading thus to sulfamates and sulfamides, respectively) [...].