Nitrophenylpiperazine derivatives as novel tyrosinase inhibitors: design, synthesis, and in silico evaluations.

A novel series of 4-nitrophenylpiperazine derivatives (4a-m) was designed and synthesized as potential tyrosinase inhibitors. Comprehensive characterization using 1H-NMR, 13C-NMR, CNH, and IR techniques was performed for all target compounds. Subsequently, the derivatives were evaluated for their inhibitory activity against tyrosinase. Among them, compound 4l, featuring an indole moiety at the N-1 position of the piperazine ring, exhibited a significant tyrosinase inhibitory effect with an IC50 value of 72.55 µM. Enzyme kinetics analysis revealed that 4l displayed mixed inhibition of the tyrosinase enzymatic reaction. Molecular docking was carried out in the enzyme's active site to further investigate the enzyme-inhibitor interactions. Based on the findings, compound 4l shows promise as a lead structure for the design of potent tyrosinase inhibitors. This study paves the way for the development of more effective tyrosinase inhibitors for potential applications in various fields.

New phenylthiosemicarbazide-phenoxy-1,2,3-triazole-N-phenylacetamides as dual inhibitors against α-glucosidase and PTP-1B for the treatment of type 2 diabetes.

This study describes the design, synthesis, and evaluation of a novel series of phenylthiosemicarbazide-phenoxy-1,2,3-triazole-N-phenylacetamide derivatives (7a-l) as dual inhibitors of α-glucosidase and protein tyrosine phosphatase 1-B (PTB-1B). The latter enzymes are two important targets in the treatment of type 2 diabetes. The in vitro obtained data demonstrated that all title compounds 7a-l were more potent than the standard inhibitor acarbose against α-glucosidase while only four derivatives (7a, 7g, 7h, and 7h) were more potent than the standard inhibitor suramin against PTP-1B. Furthermore, these data showed that the most potent α-glucosidase inhibitor was compound 7i, with sixfold higher inhibitory activity than acarbose, and the most potent PTP-1B inhibitor was compound 7a with 3.5-fold higher inhibitory activity than suramin. Kinetic studies of compounds 7i and 7a revealed that they inhibited their target enzymes in a competitive mode. The docking study demonstrated that compounds 7i and 7a well occupied the active site pockets of α-glucosidase and PTP-1B, respectively. In silico pharmacokinetic and toxicity assays of the most potent compounds were performed, and the obtained results were compared with those of the standard inhibitors.

Aryl-quinoline-4-carbonyl hydrazone bearing different 2-methoxyphenoxyacetamides as potent α-glucosidase inhibitors; molecular dynamics, kinetic and structure-activity relationship studies.

Regarding the important role of α-glucosidase enzyme in the management of type 2 diabetes mellitus, the current study was established to design and synthesize aryl-quinoline-4-carbonyl hydrazone bearing different 2-methoxyphenoxyacetamide (11a-o) and the structure of all derivatives was confirmed through various techniques including IR, 1H-NMR, 13C-NMR and elemental analysis. Next, the α-glucosidase inhibitory potentials of all derivatives were evaluated, and all compounds displayed potent inhibition with IC50 values in the range of 26.0 ± 0.8-459.8 ± 1.5 µM as compared to acarbose used as control, except 11f and 11l. Additionally, in silico-induced fit docking and molecular dynamics studies were performed to further investigate the interaction, orientation, and conformation of the newly synthesized compounds over the active site of α-glucosidase.

Design and synthesis of novel ureido and thioureido conjugated hydrazone derivatives with potent anticancer activity.

BACKGROUND: Compounds possessing urea/thiourea moiety have a wide range of biological properties including anticancer activity. On the other hand, taking advantage of the low toxicity and structural diversity of hydrazone derivatives, they are presently being considered for designing chemical compounds with hydrazone moiety in the field of cancer treatment. With this in mind, a series of novel ureido/thioureido derivatives possessing a hydrazone moiety bearing nitro and chloro substituents (4a-4i) have been designed, synthesized, characterized and evaluated for their in vitro cytotoxic effect on HT-29 human colon carcinoma and HepG2 hepatocarcinoma cell lines. RESULTS: Two compounds (4c and 4e) having the chloro phenylurea group hybridized with phenyl hydrazone bearing nitro or chloro moieties demonstrated potent anticancer effect with the IC50 values between 2.2 and 4.8 µM at 72 h. The mechanism of action of compound 4c was revealed in hepatocellular carcinoma cells as an inducer of apoptosis in a caspase-independent pathway. CONCLUSION: Taken together, the current work presented compound 4c as a potential lead compound in developing future hepatocellular carcinoma chemotherapy drugs. METHODS: The compounds were synthesized and then characterized by physical and spectral data (FT-IR, 1H-NMR, 13C-NMR, Mass). The anticancer activity was assessed using MTT assay, flowcytometry, annexin-V, DAPI staining and Western blot analysis.

Docking study, molecular dynamic, synthesis, anti-α-glucosidase assessment, and ADMET prediction of new benzimidazole-Schiff base derivatives.

The control of postprandial hyperglycemia is an important target in the treatment of type 2 diabetes mellitus (T2DM). As a result, targeting α-glucosidase as the most important enzyme in the breakdown of carbohydrates to glucose that leads to an increase in postprandial hyperglycemia is one of the treatment processes of T2DM. In the present work, a new class of benzimidazole-Schiff base hybrids 8a-p has been developed based on the potent reported α-glucosidase inhibitors. These compounds were synthesized by sample recantations, characterized by 1H-NMR, 13C-NMR, FT-IR, and CHNS elemental analysis, and evaluated against α-glucosidase. All new compounds, with the exception of inactive compound 8g, showed excellent inhibitory activities (60.1 ± 3.6-287.1 ± 7.4 µM) in comparison to acarbose as the positive control (750.0 ± 10.5). Kinetic study of the most potent compound 8p showed a competitive type of inhibition (Ki value = 60 µM). In silico induced fit docking and molecular dynamics studies were performed to further investigate the interaction, orientation, and conformation of the title new compounds over the active site of α-glucosidase. In silico druglikeness analysis and ADMET prediction of the most potent compounds demonstrated that these compounds were druglikeness and had satisfactory ADMET profile.

Design and synthesis of new N-thioacylated ciprofloxacin derivatives as urease inhibitors with potential antibacterial activity.

A new series of N-thioacylated ciprofloxacin 3a-n were designed and synthesized based on Willgerodt-Kindler reaction. The results of in vitro urease inhibitory assay indicated that almost all the synthesized compounds 3a-n (IC50 = 2.05 ± 0.03-32.49 ± 0.32 µM) were more potent than standard inhibitors, hydroxyurea (IC50 = 100 ± 2.5 µM) and thiourea (IC50 = 23 ± 0.84 µM). The study of antibacterial activity against Gram-positive species (S. aureus and S. epidermidis) revealed that the majority of compounds were more active than ciprofloxacin as the standard drug, and 3h derivative bearing 3-fluoro group had the same effect as ciprofloxacin against Gram-negative bacteria (P. aeruginosa and E. coli). Based on molecular dynamic simulations, compound 3n exhibited pronounced interactions with the critical residues of the urease active site and mobile flap pocket so that the quinolone ring coordinated toward the metal bi-nickel center and the essential residues at the flap site like His593, His594, and Arg609. These interactions caused blocking the active site and stabilized the movement of the mobile flap at the entrance of the active site channel, which significantly reduced the catalytic activity of urease. Noteworthy, 3n also exhibited IC50 values of 5.59 ± 2.38 and 5.72 ± 1.312 µg/ml to inhibit urease enzyme against C. neoformans and P. vulgaris in the ureolytic assay.

Design, synthesis, in vitro α-glucosidase inhibition, docking, and molecular dynamics of new phthalimide-benzenesulfonamide hybrids for targeting type 2 diabetes.

In the present work, a new series of 14 novel phthalimide-benzenesulfonamide derivatives 4a-n were synthesized, and their inhibitory activity against yeast α-glucosidase was screened. The obtained results indicated that most of the newly synthesized compounds showed prominent inhibitory activity against α-glucosidase. Among them, 4-phenylpiperazin derivative 4m exhibited the strongest inhibition with the IC50 value of 52.2 ± 0.1 µM. Enzyme kinetic study of compound 4m proved that its inhibition mode was competitive and Ki value of this compound was calculated to be 52.7 µM. In silico induced fit docking and molecular dynamics studies were performed to further investigate the interaction, orientation, and conformation of the target compounds over the active site of α-glucosidase. Obtained date of these studies demonstrated that our new compounds interacted as well with the α-glucosidase active site with the acceptable binding energies. Furthermore, in silico druglikeness/ADME/Toxicity studies of compound 4m were performed and predicted that this compound is druglikeness and has good ADME and toxicity profiles.

Synthesis and in vitro urease inhibitory activity of 5-nitrofuran-2-yl-thiadiazole linked to different cyclohexyl-2-(phenylamino)acetamides, in silico and kinetic studies.

A series of 5-nitrofuran-2-yl-thiadiazole linked to different cyclohexyl-2-(phenylamino)acetamides were rationally designed and synthesized. All synthetic compounds were evaluated for their urease inhibitory activity and exhibited good inhibitory potential against urease with IC50 values in the range of 0.94 - 6.78 µM as compared to the standard thiourea (IC50 = 22.50 µM). Compound 8g (IC50 = 0.94 µM) with a thiophene substituent at the R2 position was found to be the most active member of the series. Kinetic studies exhibited that the compound 8g was a non-competitive inhibitor. In silicostudy showed the critical interactions of potent inhibitors with the active site of the enzyme. These newly identified inhibitors of the urease enzyme can serve as leads for further research and development.

Phenothiazine as novel human superoxide dismutase modulators: discovery, optimization, and biological evaluation.

Superoxide dismutases (SODs) are regarded as important antioxidants for protecting cells against damage arising from oxidative stress. Much research is focused on finding new chemicals with an ability to boost human SOD activity. In the research described herein a structure-based approach was used to identify new human Cu-Zn superoxide dismutase (SOD1) modulators based on previously reported plasmodium falciparum iron SOD inhibitors using induced fit docking and molecular dynamic (MD) protocols. The compound with the highest docking binding energy was selected for further structure simplification followed by structural similarity and MD in order to find a new activator/inhibitor scaffold of the SOD1 enzyme. According to the docking survey of the mentioned series, 1,4-bis(3-(1,4,8-trichloro-10Hphenothiazin-10-yl) propyl) piperazine (DS88) was the top scoring compound interacting with the SOD1 active site channel. Following structure simplification and similarity search, the most promising scaffold which is closely related to the phenothiazine antipsychotic class, was identified. Compared with the normal blood SOD1 activity, the percent of O2 production increased with trifluoperazine, while it decreased with the chlorpromazine. The molecular dynamic investigation shows that trifluoperazine exerts its SOD1 activating effect by stabilizing electrostatic loop while chlorpromazine employs SOD1 inhibition activity through repositioning of the electrostatic loop and increasing its distance from the catalytic metal site which diminished substrate specificity and catalytic activity of the SOD1 enzyme. The results identified the preferred region, orientation, and types of interaction for each activator or inhibitor compound.

Design, synthesis, and preliminary pharmacological evaluation of novel thiazolidinone derivatives as potential benzodiazepine agonists.

Thiazolidinones are well-known heterocycles that demonstrate promising biological effects such as anticonvulsant activity. Hybridization of these chemicals with scaffold, which has necessary pharmacophores for binding to the benzodiazepine receptors, can prompt a novel structure possessing extensive anticonvulsant effects. In this study, novel derivatives of thiazolidinone as new benzodiazepine agonists were designed, synthesized, and biologically evaluated. Compound 5h, 4-chloro-2-(2-fluorophenoxy)-N-(4-oxo-2-(p-tolyl)thiazolidin-3-yl)benzamide, exhibited considerable anticonvulsant activity, proper sedative-hypnotic effect, no memory impairment, and no muscle relaxant effect. The pharmacological effects of the designed compounds were antagonized by flumazenil, which confirmed the benzodiazepine receptors' involvement in their biological effects. Based on in silico calculations of ADME properties of our novel compounds, they could be active oral agents potentially. In this study, we designed novel structures by the hybridization of thiazolidinone moiety with scaffold which has necessary pharmacophores for binding to the benzodiazepine receptors. The results are very promising for developing new lead compounds as benzodiazepine agonists possess anticonvulsant effects.

Synthesis and Decarboxylation of Functionalized 2-Pyridone-3-carboxylic Acids and Evaluation of their Antimicrobial Activity and Molecular Docking.

The functionalized 2-pyridone-3-carboxylic acids were synthesized starting from 3-formylchromone. Meanwhile, a decarboxylation reaction of 2-pyridone-3-carboxylic acid was performed by potassium carbonate in toluene. All compounds were evaluated against two Gram-negative bacteria (Escherichia coli (E. coli), Acinetobacter baumannii (A. baumannii)) and two Gram-positive (Staphylococcus aureus (S. aureus)) and fungus (Candida albicans (C. albicans)) using serial broth dilution method. The antimicrobial screening revealed that S. aureus is the highest sensitive microorganism towards the synthesized compounds. Among all analogs, derivatives, 4p and 5c showed excellent activities in comparison with the other compounds against S. aureus. Molecular docking showed that the most active anti S. aureus are compounds 4p and 5c exhibiting primary interaction as with fluoroquinolones by cross-linking over DNA gyrase active site via metal ion bridge and H-bonding interaction with Ser84 and Glu88 from GyrA subunit along with Arg458 and Asp437 located at GyrB subunit. In addition, based on the molecular dynamic simulation as like the standard fluoroquinolones, the mentioned compounds were stabilized for significant amount of simulation time over DNA gyrase which potentiate the importance of the mentioned residues in the DNA gate region of DNA gyrase.

Design, synthesis, biological evaluation, and molecular modeling studies of pyrazole-benzofuran hybrids as new α-glucosidase inhibitor.

In this work, new derivatives of biphenyl pyrazole-benzofuran hybrids were designed, synthesized and evaluated in vitro through enzymatic assay for inhibitory effect against α-glucosidase activity. Newly identified inhibitors were found to be four to eighteen folds more active with IC50 values in the range of 40.6 ± 0.2-164.3 ± 1.8 µM, as compared to the standard drug acarbose (IC50 = 750.0 ± 10.0 µM). Limited Structure-activity relationship was established. A kinetic binding study indicated that most active compound 8e acted as the competitive inhibitors of α-glucosidase with Ki = 38 µM. Molecular docking has also been performed to find the interaction modes responsible for the desired inhibitory activity. As expected, all pharmacophoric features, used in the design of the hybrid, are involved in the interaction with the active site of the enzyme. In addition, molecular dynamic simulations showed compound 8e oriented vertically into the active site from mouth to the bottom and stabilized the enzyme domains by interacting with the interface of domain A and domain B and the back side of the active site while acarbose formed non-binding interaction with the residue belong to the domain A of the enzyme.

Design, synthesis, and α-glucosidase-inhibitory activity of phenoxy-biscoumarin-N-phenylacetamide hybrids.

Thirteen new phenoxy-biscoumarin-N-phenylacetamide derivatives (7a-m) were designed based on a molecular hybridization approach as new α-glucosidase inhibitors. These compounds were synthesized with high yields and evaluated in vitro for their inhibitory activity against yeast α-glucosidase. The obtained results revealed that a significant proportion of the synthesized compounds showed considerable α-glucosidase-inhibitory activity in comparison to acarbose as a positive control. Representatively, 2-(4-(bis(4-hydroxy-2-oxo-2H-chromen-3-yl)methyl)phenoxy)-N-(4-bromophenyl)acetamide (7f), with IC50 = 41.73 ± 0.38 µM against α-glucosidase, was around 18 times more potent than acarbose (IC50 = 750.0 ± 10.0 µM). This compound was a competitive α-glucosidase inhibitor. Molecular modeling and dynamic simulation of these compounds confirmed the obtained results through in vitro experiments. Prediction of the druglikeness/ADME/toxicity of the compound 7f and comparison with the standard drug acarbose showed that the new compound 7f was probably better than the standard drug in terms of toxicity.

Design and synthesis of novel quinazolinone-pyrazole derivatives as potential α-glucosidase inhibitors: Structure-activity relationship, molecular modeling and kinetic study.

In this study, a new series of quinazolinone-pyrazole hybrids were designed, synthesized and screened for their α-glucosidase inhibitory activity. The results of the in vitro screening indicated that all the molecular hybrids exhibited more inhibitory activity (IC50 values ranging from 60.5 ± 0.3 µM-186.6 ± 20 µM) in comparison to standard acarbose (IC50 = 750.0 ± 10.0 µM). Limited structure-activity relationship suggested that the variation in the inhibitory activities of the compounds affected by different substitutions on phenyl rings of diphenyl pyrazole moiety. The enzyme kinetic studies of the most potent compound 9i revealed that it inhibited α-glucosidase in a competitive mode with a Ki of 56 µM. Molecular docking study was performed to predict the putative binding interaction. As expected, all pharmacophoric moieties used in the initial structure design playing a pivotal role in the interaction with the binding site of the enzyme. In addition, by performing molecular dynamic investigation and MM-GBSA calculation, we investigated the difference in structural perturbation and dynamic behavior that is observed over α-glycosidase in complex with the most active compound and acarbose relative to unbound α-glycosidase enzyme.

Arylmethylene hydrazine derivatives containing 1,3-dimethylbarbituric moiety as novel urease inhibitors.

A new series of arylmethylene hydrazine derivatives bearing 1,3-dimethylbarbituric moiety 7a-o were designed, synthesized, and evaluated for their in vitro urease inhibitory activity. All the title compounds displayed high anti-urease activity, with IC50 values in the range of 0.61 ± 0.06-4.56 ± 0.18 µM as compared to the two standard inhibitors hydroxyurea (IC50 = 100 ± 0.15 µM) and thiourea (IC50 = 23 ± 1.7 µM). Among the synthesized compounds, compound 7h with 2-nitro benzylidene group was found to be the most potent compound. Kinetic study of this compound revealed that it is a mix-mode inhibitor against urease. Evaluation of the interaction modes of the synthesized compounds in urease active site by molecular modeling revealed that that compounds with higher urease inhibitor activity (7h, 7m, 7c, 7l, 7i, and 7o, with IC50 of 0.61, 0.86, 1.2, 1.34, 1.33, 1.94 µM, respectively) could interact with higher number of residues, specially Arg609, Cys592 (as part of urease active site flap) and showed higher computed free energy, while compounds with lower urease activity (7f, 7n, 7g, and 7a with IC50 of 3.56, 4.56, 3.62 and 4.43 µM, respectively) and could not provide the proper interaction with Arg609, and Cys592 as the key interacting residues along with lower free binding energy. MD investigation revealed compound 7h interacted with Arg609 and Cys592 which are of the key residues at the root part of mobile flap covering the active site. Interacting with the mentioned residue for a significant amount of time, affects the flexibility of the mobile flap covering the active site and causes inhibition of the ureolytic activity. Furthermore, in silico physico-chemical study of compounds 7a-o predicted that all these compounds are drug-likeness with considerable orally availability.

Quinazolinone-dihydropyrano[3,2-b]pyran hybrids as new α-glucosidase inhibitors: Design, synthesis, enzymatic inhibition, docking study and prediction of pharmacokinetic.

A series of new quinazolinone-dihydropyrano[3,2-b]pyran derivatives 10A-L were synthesized by simple chemical reactions and were investigated for inhibitory activities against α-glucosidase and α-amylase. New synthesized compounds showed high α-glucosidase inhibition effects in comparison to the standard drug acarbose and were inactive against α-amylase. Among them, the most potent compound was compound 10L (IC50 value = 40.1 ± 0.6 µM) with inhibitory activity around 18.75-fold more than acarboase (IC50 value = 750.0 ± 12.5 µM). This compound was a competitive inhibitor into α-glucosidase. Our obtained experimental results were confirmed by docking studies. Furthermore, the cytotoxicity of the most potent compounds 10L, 10G, and 10N against normal fibroblast cells and in silico druglikeness, ADME, and toxicity prediction of these compounds were also evaluated.

Design and synthesis of novel pyrazole-phenyl semicarbazone derivatives as potential α-glucosidase inhibitor: Kinetics and molecular dynamics simulation study.

A series of novel pyrazole-phenyl semicarbazone derivatives were designed, synthesized, and screened for in vitro α-glucosidase inhibitory activity. Given the importance of hydrogen bonding in promoting the α-glucosidase inhibitory activity, pharmacophore modification was established. The docking results rationalized the idea of the design. All newly synthesized compounds exhibited excellent in vitro yeast α-glucosidase inhibition (IC50 values in the range of 65.1-695.0 µM) even much more potent than standard drug acarbose (IC50 = 750.0 µM). Among them, compounds 8o displayed the most potent α-glucosidase inhibitory activity (IC50 = 65.1 ± 0.3 µM). Kinetic study of compound 8o revealed that it inhibited α-glucosidase in a competitive mode (Ki = 87.0 µM). Limited SAR suggested that electronic properties of substitutions have little effect on inhibitory potential of compounds. Cytotoxic studies demonstrated that the active compounds (8o, 8k, 8p, 8l, 8i, and 8a) compounds are also non-cytotoxic. The binding modes of the most potent compounds 8o, 8k, 8p, 8l and 8i was studied through in silico docking studies. Molecular dynamic simulations have been performed in order to explain the dynamic behavior and structural changes of the systems by the calculation of the root mean square deviation (RMSD) and root mean square fluctuation (RMSF).

New 1,2,3-triazole-(thio)barbituric acid hybrids as urease inhibitors: Design, synthesis, in vitro urease inhibition, docking study, and molecular dynamic simulation.

A new series of 1,2,3-triazole-(thio)barbituric acid hybrids 8a-n was designed and synthesized on the basis of potent pharmacophores with urease inhibitory activity. Therefore, these compounds were evaluated against Helicobacter pylori urease. The obtained result demonstrated that all the synthesized compounds, 8a-n, were more potent than the standard urease inhibitor, hydroxyurea. Moreover, among them, compounds 8a, 8c-e, 8g,h, and 8k,l exhibited higher urease inhibitory activities than the other standard inhibitor used: thiourea. Docking studies were performed with the synthesized compounds. Furthermore, molecular dynamic simulation of the most potent compounds, 8e and 8l, showed that these compounds interacted with the conserved residues Cys592 and His593, which belong to the active site flap and are essential for enzymatic activity. These interactions have two consequences: (a) blocking the movement of a flap at the entrance of the active site channel and (b) stabilizing the closed active site flap conformation, which significantly reduces the catalytic activity of urease. Calculation of the physicochemical and topological properties of the synthesized compounds 8a-n predicted that all these compounds can be orally active. The ADME prediction of compounds 8a-n was also performed.

Synthesis, Biological Evaluation and Molecular Docking of Deferasirox and Substituted 1,2,4-Triazole Derivatives as Novel Potent Urease Inhibitors: Proposing Repositioning Candidate.

A series of new deferasirox derivatives were synthesized through the reaction of monosubstituted hydrazides with 2-(2-hydroxyphenyl)-4H-benzo[e][1,3]oxazin-4-one. For the first time, deferasirox and some of its derivatives were evaluated for their in vitro inhibitory activity against Jack bean urease. The potencies of the members of this class of compounds are higher than that of acetohydroxamic acid. Two compounds, bearing tetrazole and hydrazine derivatives (bioisoester of carboxylate group), represented the most potent urease inhibitory activity with IC50 values of 1.268 and 3.254 µm, respectively. In silico docking studies were performed to delineate possible binding modes of the compounds with the enzyme, urease. Docking analysis suggests that the synthesized compounds were anchored well in the catalytic site and extending to the entrance of binding pocket and thus restrict the mobility of the flap by interacting with its crucial amino acid residues, CME592 and His593. The overall results of urease inhibition have shown that these target compounds can be further optimized and developed as a lead skeleton for the discovery of novel urease inhibitors.

Design, Synthesis, Molecular Docking, and Cholinesterase Inhibitory Potential of Phthalimide-Dithiocarbamate Hybrids as New Agents for Treatment of Alzheimer's Disease.

A novel series of phthalimide-dithiocarbamate hybrids was synthesized and evaluated for in vitro inhibitory potentials against acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). The anti-cholinesterase results indicated that among the synthesized compounds, the compounds 7g and 7h showed the most potent anti-AChE and anti-BuChE activities, respectively. Molecular docking and dynamic studies of the compounds 7g and 7h, respectively, in the active site of AChE and BuChE revealed that these compounds as well interacted with studied cholinesterases. These compounds also possessed drug-like properties and were able to cross the BBB.