Inhibition of acetylcholinesterase and butyrylcholinesterase with uracil derivatives: kinetic and computational studies.

Acetylcholinesterase (AChE) and Butyrylcholinesterase (BuChE) inhibitors are interesting compounds for different therapeutic applications, among which Alzheimer's disease. Here, we investigated the inhibition of these cholinesterases with uracil derivatives. The mechanism of inhibition of these enzymes was observed to be due to obstruction of the active site entrance by the inhibitors scaffold. Molecular docking and molecular dynamics (MD) simulations demonstrated the possible key interactions between the studied ligands and amino acid residues at different regions of the active sites of AChE and BuChE. Being diverse of the classical AChE and BuChE inhibitors, the investigated uracil derivatives may be used as lead molecules for designing new therapeutically effective enzyme inhibitors.

Determination of the inhibitory effects of N-methylpyrrole derivatives on glutathione reductase enzyme.

Glutathione reductase (GR) is a crucial antioxidant enzyme which is responsible for the maintenance of antioxidant GSH molecule. Antimalarial effects of some chemical molecules are attributed to their inhibition of GR, thus inhibitors of this enzyme are expected to be promising candidates for the treatment of malaria. In this work, GR inhibitory properties of N-Methylpyrrole derivatives are reported. It was found that all compounds have better inhibitory activity than the strong GR inhibitor N,N-bis(2-chloroethyl)-N-nitrosourea, especially three molecules, 8 m, 8 n, and 8 q, were determined to be the most powerful among them. Findings of our study indicates that these Schiff base derivatives are strong GR inhibitors which can be used as leads for designation of novel antimalarial candidates.

Synthesis and carbonic anhydrase inhibitory properties of novel uracil derivatives.

Carbonic anhydrase (CA) inhibitors are valuable molecules based on several therapeutic applications, including antiglaucoma activity. In the present study, inhibition of two human cytosolic carbonic anhydrase isozymes I and II with some uracil derivatives (3-9) were investigated. Compounds 3-9 showed KI values in the range of 10.83-464 µM for hCA I and of 28.88-778.5 µM against hCA II, respectively. Kinetic investigations showed that similarly to classical CA inhibitors, all investigated natural compounds act as competitive inhibitors with 4-NPA as substrate. Uracil derivatives investigated here are promising agents which may be used as lead molecules in order to derivative novel carbonic anhydrase inhibitors that might be useful in medical applications.

Synthesis of 1,4-bis(indolin-1-ylmethyl)benzene derivatives and their structure-activity relationships for the interaction of human carbonic anhydrase isoforms I and II.

Several 1,4-bis(indolin-1-ylmethyl)benzene-based compounds containing substituents such as five, six and seven cyclic derivatives on indeno part (9a-c) were prepared and tested against two members of the pH regulatory enzyme family, carbonic anhydrase (CA). The inhibitory potencies of the compounds at the human isoforms hCA I and hCA II targets were analyzed and KI values were calculated. KI values of compounds for hCA I and hCA II human isozymes were measured in the range of 39.3-42.6µM and 0.17-0.29µM, respectively. The structurally related compound indole was also tested in order to understand the structure-activity relationship. Most of the compounds showed good CA inhibitory efficacy. In silico docking studies of these derivatives within hCA I and II were also carried out and results are supported the kinetic assays.

Synthesis of novel mono and bis-indole conduritol derivatives and their α/ß-glycosidase inhibitory effects.

Here we synthesized four novel indole conduritol derivatives 1-4 for the first time in the literature and probed their biological activities with the α and ß-glucosidases. The compounds showed quite effective glucosidase inhibitory action. IC(50) values of the compounds were compared with the known glucosidase inhibitor acarbose and it was determined that newly synthesized indole conduritols had more powerful effect against ß-glucosidase in addition to exhibiting moderate influence against α-glucosidase. Our molecules thus constitute an important starting point for the design and exploitation of novel glucosidase inhibitors since glucosidase inhibitors have widespread applications in the treatment of diabetes, viral infections, lysosomal storage diseases and cancers.

Structure-activity relationships for the interaction of 5,10-dihydroindeno[1,2-b]indole derivatives with human and bovine carbonic anhydrase isoforms I, II, III, IV and VI.

Several 5,10-dihydroindeno[1,2-b]indole derivatives incorporating methoxy, hydroxyl, and halogen (F, Cl, and Br) moieties on the indene fragment of the molecule were prepared and tested against five carbonic anhydrase (CA, EC 4.2.1.1) isoforms. The inhibitory potencies of these compounds against the human (h) isoforms hCA I, II, IV, VI and bovine (b) isoform bCA III were assessed. Most of them exhibited low micromolar inhibition of these enzymes. K(I) values of these compounds against hCA I and hCA II were in the range of 2.14-16.32 µM, and 0.34-2.52 µM, respectively. Isozyme hCA IV was inhibited with K(I)-s in the range of 0.435-5.726 µM, while hCA VI with K(I)-s of 1.92-12.84 µM bCA III was inhibited with K(I)-s in the range of 2.13-17.83 µM. The structurally related compounds, 1,2-dimethoxybenzene, catechol and indole were also tested in order to understand the structure activity relationship. In silico docking studies of some derivatives within the active site of hCA I and II were also carried out in order to rationalize the inhibitory properties of these compounds and understand their inhibition mechanism.

α-Carbonic anhydrases are sulfatases with cyclic diol monosulfate esters.

Carbonic anhydrases (CA) catalyze activated ester hydrolysis in addition to the hydration of CO(2) to bicarbonate. They also show phosphatase activity with 4-nitrophenyl phosphate as substrate but not sulfatase with the corresponding sulfate. Here we prove that the enzyme is catalyzing the synthesis of cyclic diols from sulfate esters. 5-, 6- and 8-membered ring cyclic sulfates incorporating a neighboring secondary alcohol moiety were treated with CA II and yielded the corresponding cyclic diols. Inhibitory properties of obtained cyclic and original sulfate esters were then investigated on human carbonic anhydrase I (hCA I), hCA II, hCA IV and hCA VI (h = human isoform). K(I)-s of these compounds ranged between 32.7-423 µM against hCA I, 2.13-32.4 µM against hCA II, 13.7-234 µM against hCA IV and 76-278 µM against CA VI, respectively. The sulfatase activity of CA with such esters is amazing considering the fact that 4-nitrophenyl-sulfate is not a substrate of these enzymes.

NO-releasing esters show carbonic anhydrase inhibitory action against human isoforms I and II.

Carbonic anhydrase (CA, EC 4.2.1.1) inhibitors (CAIs) are a class of pharmaceuticals used as antiglaucoma agents, diuretics, antiepileptics, in the management of mountain sickness, gastric and duodenal ulcers, neurological disorders, or osteoporosis. We report here the inhibitory capacities of some organic nitrates against two human (hCA) isozymes, hCA I and hCA II. The IC(50) values of compounds 1-12 against hCA I ranged between 7.13mM and 124mM, and against hCA II between 65.1microM and 0.79mM. Nitrate esters are thus interesting hCA I and II inhibitors, and might be used as leads for generating enzyme inhibitors eventually targeting other isoforms which have not been assayed yet for their interactions with such agents.

In vitro inhibition of human erythrocyte glutathione reductase by some new organic nitrates.

Glutathione reductase (GR), is responsible for the existence of GSH molecule, a crucial antioxidant against oxidative stress reagents. The antimalarial activities of some redox active compounds are attributed to their inhibition of antioxidant flavoenzyme glutathione reductase, and inhibitors are therefore expected to be useful for the treatment of malaria. Twelve organic nitrate derivatives were synthesized and treated with human erythrocyte GR. The molecules were identified as strong GR inhibitors and novel antimalaria candidates.

Synthesis of new 2-vinylation products of indole via a Michael-type addition reaction with dimethyl acetylenedicarboxylate and their Diels-Alder reactivity as precursors of new carbazoles.

Reaction of 4,7-dihydroindole and dimethyl acetylenedicarboxylate provided a convenient route to functionalized 2-vinylindoles. Diels-Alder reactions of the 2-vinylindoles with naphthoquinone, p-benzoquinone, 1,2-dicyano-4,5-dichloroquinone, N-phenyltriazolinedione, and tetracyanoethylene were investigated to give [c]annelated 1,2-dihydro, 1,2,3,4-tetrahydro, and fully aromatized carbazoles. The structure and formation mechanism of both 2-vinylindoles and their cycloadduct are discussed.