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In this study, a library of twelve beta-lactam-substituted benzenesulfonamides ( 5a-l ) was synthesized using the tail-approach method. The compounds were characterized using IR, 1 H NMR, 13 C NMR and elemental analysis techniques. These newly synthesized compounds were tested for their ability to inhibit the activity of two carbonic anhydrases ( h CA) isoforms, I and II, and acetylcholinesterase (AChE) in vitro . The results showed that the synthesized compounds were potent inhibitors of h CA I, with K I s in the low nanomolar range (66.60-278.40 nM) than the reference drug acetazolamide (AAZ), which had a K I of 439.17 nM. The h CA II was potently inhibited by compounds 5a , 5d-g and 5l , with K I s of 69.56, 39.64, 79.63, 74.76, 78.93 and 74.94 nM, respectively (AAZ, K I of 98.28 nM). Notably, compound 5a selectively inhibited h CA II with a selectivity of > 4-fold over h CA I. In terms of inhibition of AChE, the synthesized compounds had K I s ranging from 30.95 to 154.50 nM, compared to the reference drug tacrine, which had a K I of 159.61 nM. Compounds 5f , 5h and 5l were also evaluated for their ability to inhibit the MCF-7 cancer cell line proliferation and were found to have promising anticancer activity, more potent than 5-fluorouracil and cisplatin. Molecular docking studies suggested that the sulfonamide moiety of these compounds fits snugly into the active sites of h CAs and interacts with the Zn 2+ ion. Furthermore, molecular dynamics simulations were performed for 200 ns to assess the stability and dynamics of each enzyme-ligand complex. The acceptability of the compounds based on Lipinski's and Jorgensen's rules was also estimated from the ADME/T results. These results indicate that the synthesized molecules have the potential to be developed into effective and safe inhibitors of h CAs and AChE and could be lead agents.Communicated by Ramaswamy H. Sarma.

Various carbonic anhydrase (CA) enzyme isoforms are known today. In addition to the use of CA inhibitors as diuretics, antiepileptics and antiglaucoma agents, the inhibition of other specific isoforms of CA was reported to have clinical benefits in cancers. In this study, two groups of 1,3,4-thiadiazole derivatives were designed and synthesized to act as human CA I and II ( h CA I and h CA II) inhibitors. The activities of these compounds were tested in vitro and evaluated in silico studies. The activity of the synthesized compounds was also tested against acetylcholinesterase (AChE) to evaluate the relation of the newly designed structures to the activity against AChE. The synthesized compounds were analyzed by 1 H NMR, 13 C NMR and high-resolution mass spectroscopy (HRMS). The results displayed a better activity of all the synthesized compounds against h CA I than that of the commonly used standard drug, Acetazolamide (AAZ). The compounds also showed better activity against h CA II, except for compounds 5b and 6b . Only compounds 6a and 6c showed superior activity against AChE compared to the standard agent, tacrine (THA). In silico studies, including absorption, distribution, metabolism and excretion (ADME) and drug-likeness evaluation, molecular docking, molecular dynamic simulations (MDSs) and density functional theory (DFT) calculations, were compatible with the in vitro results and presented details regarding the structure-activity relationship.Communicated by Ramaswamy H. Sarma.

Carbonic Anhydrases (CAs) are an important family of metalloenzymes that contain zinc (Zn 2+ ) ions in their active site and catalyze the conversion of carbon dioxide to bicarbonate and proton and found in all living organisms. Sulfonamides are well-known inhibitors of CAs isoenzymes. In this study, a series of benzenesulfonamide derivatives (9a-h) containing 1,2,3-triazole-moiety were designed, synthesized and their structures were characterized by spectroscopic methods. In addition, molecular structures of compounds 5a, 5 b, 9e and 9f were elucidated by X-ray diffraction technique. To investigate drug similarity of 9a-h compounds, Lipinski's five rules (ADMET: absorption, distribution, metabolism, excretion and toxicity) were carried out by in silico studies. According to results, the compounds showed drug-like properties. Docking studies were applied to determine the scores, interactions and binding modes of compounds 9a-h against hCA I and hCA II enzymes. Compound 9c (-5.13 kcal/mol docking score) against hCA I enzyme and 9 h (-5.32 kcal/mol docking score) against hCA II enzyme showed potent inhibitory properties. The binding interactions of the compounds with the carbonic anhydrases were examined by docking studies.Communicated by Ramaswamy H. Sarma.

Aldose reductase (AR) and sorbitol dehydrogenase (SDH) are important enzymes of the polyol pathway. In the current study, inhibitory effects of vulpinic acid (VA) carnosic acid (CA) and usnic acid (UA) on purified AR and SDH enzymes were determined. These enzymes inhibition could be essential to prevent diabetic complications. AR and SDH enzymes were purified from sheep kidney. Then, VA, CA and UA were tested in various concentrations against these enzymes activity in vitro . K I values were found to be as 1.46 ± 0.04, 5.13 ± 0.25 and 11.71 ± 0.27 μΜ for VA, CA and UA, respectively, for AR. K I constants were found to be as 15.32 ± 0.34, 145.60 ± 2.17 and 213.40 ± 2.64 μΜ VA, CA and UA, respectively, for SDH. These findings indicate that VA, CA and UA could be useful in the treatment of diabetic complications.Communicated by Ramaswamy H. Sarma.

The underlying cause of many metabolic diseases is abnormal changes in enzyme activity in metabolism. Inhibition of metabolic enzymes such as cholinesterases (ChEs; acetylcholinesterase, AChE and butyrylcholinesterase, BChE) and α-glucosidase (α-GLY) is one of the accepted approaches in the treatment of Alzheimer's disease (AD) and diabetes mellitus (DM). Here we reported an investigation of a new series of novel ureido-substituted derivatives with sulfamethazine backbone ( 2a-f ) for the inhibition of AChE, BChE, and α-GLY. All the derivatives demonstrated activity in nanomolar levels as AChE, BChE, and α-GLY inhibitors with K I values in the range of 56.07-204.95 nM, 38.05-147.04 nM, and 12.80-79.22 nM, respectively. Among the many strong N -(4,6-dimethylpyrimidin-2-yl)-4-(3-substitutedphenylureido) benzenesulfonamide derivatives ( 2a-f ) detected against ChEs, compound 2c , the 4-fluorophenylureido derivative, demonstrated the most potent inhibition profile towards AChE and BChE. A comprehensive ligand/receptor interaction prediction was performed in silico for the three metabolic enzymes providing molecular docking investigation using Glide XP, MM-GBSA, and ADME-Tox modules. The present research reinforces the rationale behind utilizing inhibitors with sulfamethazine backbone as innovative anticholinergic and antidiabetic agents with a new mechanism of action, submitting propositions for the rational design and synthesis of novel strong inhibitors targeting ChEs and α-GLY.Communicated by Ramaswamy H. Sarma.

Many drugs, which are used in clinical treatments, show pharmacological effects on enzyme activity with an essential role in the pathogenesis of various diseases. Paraoxonase-I (PON1) is a member of the mammalian lactonase enzyme family, serves to the prevention of blood vessel plaque formation by protecting high-density lipoprotein and low-density lipoprotein against oxidation. In the current study, we aimed to contribute to drug discovery and to determine the interaction of some calcium channel blockers (CCBs) with PON1. For this purpose, first, the PON1 enzyme was purified from fresh human serum by using different chromatographic techniques. Then, the various concentrations of CCBs were tested on the paraoxonase activity of PON1. IC 50 values were found as 41.00, 48.00, and 180 µM for nimodipine, cinnarizine, and nilvadipine, respectively. PON1 was effectively inhibited by these drugs ( K i s ranging between 22.13 ± 1.13 and 174.12 ± 20.52 µM). Of these drugs, only the inhibition mechanism of cinnarizine was competitive on PON1. Besides, the molecular docking analysis of cinnarizine was applied to detailed the binding interactions on the active site of PON1. The docking scores for the Glide standard-precision (SP), and Glide extra-precision (XP) modes for 1V04 receptor monitored to be -5.001, and -6.079, respectively. We determined that the CCBs reduced PON1 enzyme activity both in vitro and in silico conditions, significantly. Therefore, further biological studies such as gene expression and in vivo experiments should be done for these drugs. Communicated by Ramaswamy H. Sarma.

Sulfonamide derivatives exhibit a wide biological activity and can function as potential medical molecules in the development of a drug. Studies have reported that the compounds have an effect on many enzymes. In this study, the derivatives of amine sulfonamide ( 1i - 11i ) were prepared with reduced imine compounds ( 1 - 11 ) with NaBH 4 in methanol. The synthesized compounds were fully characterized by spectral data and analytical. The effect of the synthesized derivatives on acetylcholinesterase (AChE), glutathione S-transferase (GST) and α-glycosidase (α-GLY) enzymes were determined. For the AChE and α-GLY, the most powerful inhibition was observed on 10 and 10i series with K I value in the range 2.26 ± 0.45-3.57 ± 0.97 and 95.73 ± 13.67-102.45 ± 11.72 µM, respectively. K I values of the series for GST were found in the range of 22.76 ± 1.23-49.29 ± 4.49. Finally, the compounds have a stronger inhibitor in lower concentrations by the attachment of functional electronegative groups such as two halogens (-Br and -CI), -OH to the benzene ring and -SO 2 NH 2 . The crystal structures of AChE, α-GLY, and GST in complex with selected derivatives 4 and 10 show the importance of the functional moieties in the binding modes within the receptors.Communicated by Ramaswamy H. Sarma.

Carbonic anhydrases (CAs) are potent dehydration of carbonic acid and catalyst of the reversible hydration of carbon dioxide. Here, CA I and CA II was purified from human erythrocytes using the simple chromatographic method and determined the interactions between some calcium channel blockers and the enzymes. Molecular docking studies were performed these compounds. It was found that calcium channel blockers (nimodipine, nilvadipine, nitrendipine, isradipine, and nifedipine) exhibit potential inhibitor properties for hCA I and hCA II. IC 50 values of hCA I were in the range of 9.24-58.00 μM, and K i constants were in the range of 7.60 ± 2.68-35.92 ± 16.01 μM. IC 50 values of hCA II were in the range of 70.00-138.60 μM, and K i constants were in the range of 48.30 ± 9.81-162.35 ± 20.47 μM. Nimodipine presented the highest docking score and had competitive inhibition, the benzene and pyridine rings were found to enter the cavity for hCA I. Nifedipine and isradipine did not affect hCA II. Among these drugs, nitrendipine was found to be the most potent inhibitor for hCA I and nimodipine for hCA II. These compounds may be useful for CA inhibitors.Communicated by Ramaswamy H. Sarma.

Sulphonamides are biologically important compounds with low toxicity, many bioactivities and cost-effectiveness. Eight sulphonamide derivatives were synthesised and characterised by FT-IR, 13 C NMR, 1 H NMR, LC-MS and elemental analysis. Their inhibitory effect on AChE, and carbonic anhydrase I and II enzyme activities was investigated. Their antioxidant activity was determined using different bioanalytical assays such as radical scavenging tests with ABTS •+ , and DPPH •+ as well as metal-reducing abilities with CUPRAC, and FRAP assays. All compounds showed satisfactory enzyme inhibitory potency in nanomolar concentrations against AChE and CA isoforms with K I values ranging from 10.14 ± 0.03 to 100.58 ± 1.90 nM. Amine group containing derivatives showed high metal reduction activity and about 70% ABTS radical scavenging activity. Due to their antioxidant activity and AChE inhibition, these novel compounds may be considered as leads for investigations in neurodegenerative diseases.

In this study, we investigated the effects of antibacterial drugs (moxifloxacin hydrochloride, levofloxacin hemihidrate, cefepime hydrochloride, cefotaxime sodium and ceftizoxime sodium) on human serum paraoxonase-1 (hPON1) enzyme activity from human serum in vitro conditions. For this purpose, hPON1 enzyme was purified from human serum using simple chromatographic methods. The antibacterial drugs exhibited inhibitory effects on hPON1 at low concentrations. Ki constants were calculated to be 2.641 ± 0.040 mM, 5.525 ± 0.817 mM, 35.092 ± 1.093 mM, 252.762 ± 5.749 mM and 499.244 ± 10.149 mM, respectively. The inhibition mechanism of moxifloxacin hydrochloride was competitive, whereas levofloxacin hemihidrate, cefepime hydrochloride, cefotaxime sodium and ceftizoxime sodium were noncompetitive inhibitors.

Three novel bromophenols 10-12 were synthesized. Acylation of veratrole (4) with 2,3-dimethoxy benzoic acid (5) gave a kown diarylmethanone 6. Bromination of 6 with different equivalents of molecular bromine afforded new di and tribrominated compounds 7-9 which were converted to their corresponding bromophenols 10-12 via O-demethylation with BBr3. Paraoxonase-1 (PON1) was purified from human serum with approximately 42% and 3584 U × mg(-1) specific activity. The synthesized compounds 6-12 showed inhibitory effects on paraoxonase-1 (PON1) which is an organophosphate (OP) hydrolyser and an antioxidant bioscavenger enzyme. IC50 values were determined in the range of 0.123-1.212 mM.