ABSTRACT
The frequent use of anti-inflammatory drugs and the side effects of existing drugs keep the need for new compounds constant. For this purpose, flurbiprofen and ibuprofen-like compounds, which are frequently used anti-inflammatory compounds in this study, were synthesized and their structures were elucidated. Like ibuprofen and flurbiprofen, the compounds contain a residue of phenylacetic acid. On the other hand, it contains a secondary amine residue. Thus, it is planned to reduce the acidity, which is the biggest side effect of NSAI drugs, even a little bit. The estimated ADME parameters of the compounds were evaluated. Apart from internal use, local use of anti-inflammatory compounds is also very important. For this reason, the skin permeability values of the compounds were also calculated. And it has been found to be compatible with reference drugs. The COX enzyme inhibitory effects of the obtained compounds were tested by in vitro experiments. Compound 2a showed significant activity against COX-1 enzyme with an IC50 = 0.123 + 0.005 µM. The interaction of the compound with the enzyme active site was clarified by molecular dynamics studies.
Subject(s)
Cyclooxygenase 1 , Cyclooxygenase Inhibitors , Flurbiprofen , Ibuprofen , Molecular Dynamics Simulation , Flurbiprofen/pharmacology , Flurbiprofen/chemistry , Ibuprofen/pharmacology , Ibuprofen/chemistry , Cyclooxygenase Inhibitors/pharmacology , Cyclooxygenase Inhibitors/chemistry , Cyclooxygenase Inhibitors/chemical synthesis , Cyclooxygenase 1/metabolism , Cyclooxygenase 1/chemistry , Anti-Inflammatory Agents, Non-Steroidal/pharmacology , Anti-Inflammatory Agents, Non-Steroidal/chemistry , Anti-Inflammatory Agents, Non-Steroidal/chemical synthesis , Humans , Catalytic Domain , Phenylacetates/chemistry , Phenylacetates/pharmacologyABSTRACT
In recent studies, monoamine oxidase (MAO) inhibitory effects of various thiazolylhydrazone derivatives have been demonstrated. Within the scope of this study, 12 new compounds containing thiazolylhydrazone groups were synthesized. The structures of the obtained compounds were elucidated by 1H NMR, 13C NMR, and high-resolution mass spectrometry (HRMS) methods. The inhibitory effects of the final compounds on MAO enzymes were investigated by means of in vitro methods. In addition to enzyme inhibition studies, enzyme kinetic studies of compounds with high inhibitory activity were examined, and their effects on substrate-enzyme relations were investigated. Additionaly, cytotoxicity tests were carried out to determine the toxicities of the selected compounds, and the compounds were found to be nontoxic. The interactions of the active compound with the active site of the enzyme were characterized by in silico methods.
ABSTRACT
Breast cancer causes a high rate of mortality all over the world. Therefore, the present study focuses on the anticancer activity of new lower rim-functionalized calix[4]arenes integrated with isatin and the p-position of calixarenes with 1,4-dimethylpyridinium iodine against various human cancer cells such as MCF-7 and MDA-MB-231 breast cancer cell lines, as well as the PNT1A healthy epithelial cell line. It was observed that compound 6c had the lowest values in MCF-7 (8.83 µM) and MDA-MB-231 (3.32 µM). Cell imaging and apoptotic activity studies were performed using confocal microscopy and flow cytometry, respectively. The confocal imaging studies with 6c showed that the compound easily entered the cell, and it was observed that 6c accumulated in the mitochondria. The Comet assay test was used to detect DNA damage of compounds in cells. It was found that treated cells had abnormal tail nuclei and damaged DNA structures compared with untreated cells. In vitro human aromatase enzyme inhibition profiles showed that compound 6c had a remarkable inhibitory effect on aromatase. Compound 6c displayed a significant inhibition capacity on aromatase enzyme with the IC50 value of 0.104 ± 0.004 µM. Thus, not only the anticancer activity of the new fluorescent derivatives, which are the subject of this study, but the aromatase inhibitory profiles have also been proven.
Subject(s)
Antineoplastic Agents , Breast Neoplasms , Isatin , Humans , Female , Aromatase Inhibitors/pharmacology , Antineoplastic Agents/chemistry , Isatin/pharmacology , Isatin/chemistry , Aromatase/metabolism , Structure-Activity Relationship , Cell Line, Tumor , Mitochondria , DNA , Cell Proliferation , Drug Screening Assays, AntitumorABSTRACT
Designing multi-targeted drugs (MTD) for Alzheimer's disease (AD) is now one of the priorities for medicinal chemists, as the disease has a complicated not fully understood pathological nature and the approved mono-targeted drugs only alleviate the symptoms. In this study, the synthesis, spectral analyses and in vitro inhibition activity against cholinesterase (ChE) and monoamine oxidase (MAO) enzymes of a novel series of N-[5-(adamantan-1-yl)-1,3,4-thiadiazol-2-yl]-2-(4-un/substituted) cyclic secondary amino-acetamide/propanamide derivatives were done. Generally, derivatives were more selective against acetylcholinesterase (AChE) and h-MAO-B than butyrylcholinesterase (BChE) and h-MAO-A, respectively. Derivatives 4a, 4b, 3a, 3d and 3b ordered from the most potent to the least displayed significant inhibition against AChE. Also, derivatives 4a, 4b and 3a still maintained their significant inhibition against h-MAO-B in the same potency order, making them dual inhibitors and MTD candidates for AD. Binding interactions with several crucial amino acid residues for activity and selectivity as well as the stability of the most active derivatives-enzyme complex were confirmed utilizing molecular docking and molecular dynamic simulation studies.Communicated by Ramaswamy H. Sarma.
Novel 2,5-disubstituted-1,3,4-thiadiazole derivatives were synthesized.The ChEs/MAOs dual inhibition activity against Alzheimer's disease was tested.Compounds 4a, 4b and 3a were active dual inhibitor against both AChE and h-MAO-B.Compounds 3d and 3b were also active against AChE.No significant inhibition activity against BChE and h-MAO-A.
ABSTRACT
Carbonic anhydrase (CA) enzymes are a common catalytic enzyme in many organisms. Vertebrates and invertebrates have different CA isoforms. Sixteen different isozymes of the α-CA isoform found in vertebrates have been identified so far. The main task of this enzyme is to catalyze the reversible conversion of carbon dioxide into bicarbonate and hydrogen ions in the body. It is widely distributed in many organs and tissues. They are involved in important physiological processes such as pH and CO2 homeostasis, biosynthetic reactions such as gluconeogenesis, lipogenesis, ureagenesis, bone resorption, calcification, tumorigenicity, and electrolyte secretion. As a result of the literature research, it has been determined that the most effective inhibitor of the carbonic anhydrase enzyme is sulfonamides. The R group in the general molecular structure of R-SO2-NH2 generally consists of aromatic or heteroaromatic ring systems. The sulfonamides interact strongly with the Zn2+ ions in the active site of the enzyme. In this study, 10 sulfonamide derivatives were synthesized. Analyses of the obtained compounds are evaluated by using 1H NMR, 13C NMR and HRMS spectroscopic methods. The inhibition effect of the obtained compounds on the carbonic anhydrase enzyme was investigated by means of in vitro kit method. For the selected compounds, docking studies were performed and the enzyme active sites and binding points were determined. It was revealed that the strongest interaction with CA enzymes (CA-I, CA-II, CA-IX, CA-XII) active sites was observed with the compound 2e.
Subject(s)
Carbonic Anhydrase Inhibitors , Carbonic Anhydrases , Animals , Carbonic Anhydrase Inhibitors/pharmacology , Carbonic Anhydrase Inhibitors/chemistry , Carbonic Anhydrases/chemistry , Carbonic Anhydrases/metabolism , Molecular Structure , Catalytic Domain , Sulfonamides/pharmacology , Sulfonamides/chemistry , Structure-Activity RelationshipABSTRACT
Donepezil is one of the most used drugs in the treatment of Alzheimer's disease. Its activity as an AChE inhibitor makes new studies with these enzyme inhibitors attractive. For this purpose, in this study, 12 compounds including thiosemicarbazone pharmacophore, have been synthesized for the treatment of the Alzheimer's disease. 3,4-Dimethoxybenzene or 1,3-benzodioxolone rings were used for the PAS region. The substituted piperazine benzene structure is preferred for the CAS region. At the same time, the thiosemicarbazone pharmacophore structure with known ChE enzyme inhibition potential was used as a bridge connecting the CAS and PAS regions. Structure determination of compounds 3a-3l were revealed using 13 C-NMR, 1 H-NMR, and HRMS spectroscopic methods. The inhibition profile of obtained compounds (3a-3l) against ChE was evaluated using in vitro modified Ellman method. Compounds 3a, 3b, 3f, 3g and 3i exhibited inhibitory activity against the AChE enzyme. Compound 3a showed the highest inhibitory potential with an IC50 = 0.030 ± 0.001 µM. As a result of molecular docking studies, compound 3a displayed important interactions compared to other active derivatives. Molecular dynamics studies are important to see the stability of the complex formed by ligand and protein. RMSD, RMSF ang Rg parameters were calculated via dynamic studies. In conclusion, compound 3a may be a potential AChE enzyme inhibitor with its strong inhibitory potential and behavior in silico.
Subject(s)
Alzheimer Disease , Thiosemicarbazones , Humans , Molecular Docking Simulation , Alzheimer Disease/drug therapy , Molecular Dynamics Simulation , Cholinesterase Inhibitors/pharmacology , Cholinesterase Inhibitors/chemistry , Thiosemicarbazones/pharmacology , Thiosemicarbazones/therapeutic use , Enzyme Inhibitors/pharmacology , Acetylcholinesterase/chemistry , Acetylcholinesterase/metabolism , Structure-Activity Relationship , Molecular StructureABSTRACT
Lung cancer is one of the most common cancer types of cancer with the highest mortality rates. However, while epidermal growth factor receptor (EGFR) is an important parameter for lung cancer, EGFR inhibitors also show great promise in the treatment of the disease. Therefore, a series of new EGFR inhibitor candidates containing thiadiazole and pyrazole rings have been developed. The activities of the synthesized compounds were elucidated by in vitro MTT, (which is chemically 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide), cytotoxicity assay, analysis of mitochondrial membrane potential (MMP) by flow cytometry, and EGFR inhibition experiments. Molecular docking and molecular dynamics simulations were performed as in silico studies. Compounds 6d, 6g, and 6j showed inhibitor activity against the A549 cell line with IC50 = 5.176 ± 0.164; 1.537 ± 0.097; and 8.493 ± 0.667 µM values, respectively. As a result of MMP by flow cytometry, compound 6g showed 80.93% mitochondrial membrane potential. According to the results of the obtained EGFR inhibitory assay, compound 6g shows inhibitory activity on the EGFR enzyme with a value of IC50 = 0.024 ± 0.002 µM.
ABSTRACT
In the search for new anticancer agents, we synthesized a new series of thiazole derivatives carried on thiadiazole-oxadiazole hybrid. Final compounds (5a-5i) were analyzed via 1H NMR, 13C NMR, and HRMS. The pharmacokinetic profile of the targeted compounds was predicted via in silico calculations. Their anticancer properties were determined using MTT method against MCF7 and A549 cell lines. Compounds 5a, 5b and 5c were found more active against MCF7 cells than A549 cells while they were not cytotoxic on L929 healthy cells. Generally, it can be summarized that acetamide moiety has a pivotal role in anticancer activity. For further studies, their aromatase inhibitory activity was evaluated. After determination all these features, the binding modes of the active compounds and the stability and relation of the ligand-enzyme complex were investigated using molecular docking and molecular dynamics simulation studies, respectively. In vitro and in silico studies suggest two important structure-activity relationship (SAR) points that at least one azole ring is essential, and if there is approximately 8.0 ± 0.5 Å distance between the H-bond rich zone of ligand and the heteroaryl ring system of ligand has a major impact on aromatase inhibitory activity. Compounds with small group substitution on thiazole are found potentially may be used for the treatment of anti-breast cancer orally.Communicated by Ramaswamy H. Sarma.
ABSTRACT
Uncontrolled use of antifungal drugs affects the development of resistance to existing drugs. Azole antifungals constitute a large part of antifungal therapy. Therefore, there is a need for new azole antifungals. Within the scope of this study, 17 new triazole derivative compounds were synthesized. Structure determinations were clarified by spectroscopic analysis methods (1H-NMR, 13C-NMR, HRMS). In addition, structure matching was completed using two-dimensional NMR techniques, HSQC, HMBC and NOESY. The antifungal effects of the compounds were evaluated on Candida strains by means of in vitro method. Compound 5d showed activity against Candida glabrata with a MIC90 = 2 µg/mL. Compound 5d showed activity against Candida krusei with a MIC90 = 2 µg/mL. This activity value, which is higher than fluconazole, is promising. In addition, the biofilm inhibition percentages of the compounds were calculated. Molecular docking and molecular dynamics simulations performed with compound 5d are in harmony with activity studies.
ABSTRACT
Modification of drugs used in the clinic is a frequently used method with regards to medicinal chemistry in the development of new drugs. Acetazolamide is a drug in clinical use as a CA inhibitor. Within the scope of this study, the 'N-(5-sulfamoyl-1,3,4-thiadiazol-2-yl) acetamide' structure, which is acetazolamide residue, was kept constant; various mercaptan substitutions were made from methylene adjacent to the carbonyl group in the structure. Compounds 4c, 4d, 4e, 4 g, 4h, 4i, and 4j exhibited inhibitor activity against CA enzyme with IC50=0.238 ± 0.010, 0.161 ± 0.007, 0.067 ± 0.002, 0.084 ± 0.003, 0.033 ± 0.001, 0.049 ± 0.002 and 0.187 ± 0.008 µM, respectively. The intermolecular interactions of the promising compounds with aromatase enzyme were investigated through the SP docking approach, which revealed significant binding interaction energies associated with these compounds. To measure the stability of the compounds in the enzyme active site, dynamic studies were performed at 100 ns. In addition to the RMSD, RMSF parameters, the interaction ratios of compound 4h with amino acids in the enzyme active site and the interaction histograms were also investigated. The results obtained are quite promising. Continuous interactions were exhibited with Thr199, Glu106, His96, His94 and His119, which are important for the CA enzyme.Communicated by Ramaswamy H. Sarma.
ABSTRACT
Cyclooxygenase, also known as prostaglandin H2 synthase (PGH2), is one of the most important enzymes in pharmacology because inhibition of COX is the mechanism of action of most nonsteroidal anti-inflammatory drugs. In this study, ten thiazole derivative compounds had synthesized. The analysis of the obtained compounds was performed by 1 H NMR and 13 C NMR methods. By this method, the obtained compounds could be elucidated. The inhibitory effect of the obtained compounds on cyclooxygenase (COX) enzymes was investigated. The encoded compounds 5a, 5b, and 5c were found to be the most potent compared to the reference compounds ibuprofen (IC50 = 5.589 ± 0.278 µM), celecoxib (IC50 = 0.132 ± 0.004 µM), and nimesulide (IC50 = 1.692 ± 0.077 µM)against COX-2 isoenzyme. The inhibitory activity of 5a, 5b, and 5c is approximate, but the 5a derivative proved to be the most active in the series with an IC50 value of 0.180 ± 0.002 µM. The most potent COXs inhibitor was 5a, which was further investigated for its potential binding mode by a molecular docking study. Compound 5a was found to be localized at the active site of the enzyme, like celecoxib, which has a remarkable effect on COXs enzymes.
Subject(s)
Cyclooxygenase 2 Inhibitors , Pharmacophore , Cyclooxygenase 2 Inhibitors/chemistry , Cyclooxygenase 2 Inhibitors/pharmacology , Celecoxib , Molecular Docking Simulation , Anti-Inflammatory Agents, Non-Steroidal/chemistry , Cyclooxygenase 2/chemistry , Cyclooxygenase 2/metabolism , Structure-Activity Relationship , Molecular StructureABSTRACT
As lung cancer was placed foremost part among other types of cancer in terms of mortality. Recent researches are widely focused on developing multi-targeted and site-specific targeted drug designs. In the present study, we designed and developed a series of quinoxaline pharmacophore derivatives as active EGFR inhibitors for the treatment of non-small cell lung cancer. The compounds were synthesized through a condensation reaction between hexane-3,4-dione and methyl 3,4-diaminobenzoate as a first step. Their structures were confirmed by 1 H-NMR, 13 C-NMR, and HRMS spectroscopic methods. Cytotoxicity (MTT) were applied to determine anticancer activity of the compounds against breast (MCF7), fibroblast (NIH3 T3), and lung (A549) cell lines as EGFR inhibitors. Doxorubicin was used as a reference agent, compound 4i exhibited a significant effect among other derivatives with IC50 = 3.902 ± 0.098 µM value against A549 cell line. The docking study showed that the best position on EGFR receptor could be observed with 4i. From the obtained evaluations of the designed series, compound 4i was a promising agent as EGFR inhibitor for further investigation and evaluation studies in the future.
Subject(s)
Antineoplastic Agents , Carcinoma, Non-Small-Cell Lung , Lung Neoplasms , Humans , Molecular Docking Simulation , Molecular Structure , Structure-Activity Relationship , Quinoxalines/pharmacology , Cell Proliferation , Drug Screening Assays, Antitumor , Antineoplastic Agents/chemistry , ErbB Receptors/metabolism , Drug Design , Cell Line, Tumor , Protein Kinase Inhibitors/chemistryABSTRACT
Cancer is a progressive disease that is frequently encountered worldwide. The incidence of cancer is increasing with the changing living conditions around the world. The side-effect profile of existing drugs and the resistance developing in long-term use increase the need for novel drugs. In addition, cancer patients are not resistant to bacterial and fungal infections due to the suppression of the immune system during the treatment. Rather than adding a new antibacterial or antifungal drug to the current treatment plan, the fact that the drug with anticancer activity has these effects (antibacterial and antifungal) will increase the patient's quality of life. For this purpose, in this study, a series of 10 new naphthalene-chalcone derivatives were synthesized and their anticancer-antibacterial-antifungal properties were investigated. Among the compounds, compound 2j showed activity against the A549 cell line with an IC50 = 7.835 ± 0.598 µM. This compound also has antibacterial and antifungal activity. The apoptotic potential of the compound was measured by flow cytometry and showed apoptotic activity of 14.230%. The compound also showed 58.870% mitochondrial membrane potential. Compound 2j inhibited VEGFR-2 enzyme with IC50 = 0.098 ± 0.005 µM. Molecular docking studies of the compounds were carried out by in silico methods against VEGFR-2 and caspase-3 enzymes.
ABSTRACT
Infectious diseases are a major concern around the world. Today, it is an urgent need for new chemotherapeutics for infectious diseases. Because of that, our group designed, synthesized, and analyzed 14 new quinoline derivatives endowed with the pharmacophore moiety of fluoroquinolones primarily for their antimicrobial effects. Their cytotoxicity effects were tested against six bacterial and four fungal strains and NIH/3T3 cell line. Additionally, their action mechanisms were evaluated against DNA gyrase and lanosterol 14α-demethylase (LMD). Furthermore, to eliminate the potential side effects, the active compounds were evaluated against the aromatase enzyme. The experimental enzymatic results were evaluated for active compounds' binding modes using molecular docking and molecular dynamics simulation studies. The results were utilized to clarify the structure-activity relationship (SAR). Finally, compound 4m was the most potent compound for its antifungal activity with low cytotoxicity against healthy cells and fewer possible side effects, while compounds 4j and 4l can be used alone for special patients who are suffering from fungal infections in addition to the primer disease.
ABSTRACT
Alzheimer's disease (AD) is a progressive and fatal neurodegenerative disease that is characterized by memory and cognitive impairments that predominantly affects the elderly and is the most common cause of dementia. As is known, the AChE enzyme consists of two parts. In this work, 10 new hydrazones (3a-3j) were designed and synthesized. Naphthalene, indole, benzofuran and benzothiophene rings were used to interact with the PAS region. 4-fluorophenyl and 4-fluorobenzyl structures were preferred for interaction with the CAS region. In biological activity studies, the AChE and BChE inhibitory potentials of all compounds were evaluated using the in vitro Ellman method. The biological evaluation showed that compounds 3i and 3j displayed significant activity against AChE. The compounds 3i and 3j displayed IC50 values of 0.034 and 0.027 µM against AChE, respectively. The reference drug donepezil (IC50 = 0.021 µM) also displayed a significant inhibition against AChE. In addition, the antioxidant activities of the compounds were also evaluated. Derivatives 3i and 3j, which emerged active from both in vitro activity studies, were subjected to in vitro PAMPA tests to determine BBB permeability. Further docking simulation also revealed that these compounds (3i, 3j and donepezil) interacted with the enzyme active site in a similar manner to donepezil. A few parameters derived from MD simulation trajectories were computed and validated for the protein-ligand complex's stability under the dynamic conditions.Communicated by Ramaswamy H. Sarma.
ABSTRACT
This study delves into the intricate dynamics of the inflammatory response, unraveling the pivotal role played by cyclooxygenase (COX) enzymes, particularly COX-1 and COX-2 subtypes. Motivated by the pursuit of advancing scientific knowledge, our contribution to this field is marked by the design and synthesis of novel pyrrole derivatives. Crafted as potential inhibitors of COX-1 and COX-2 enzymes, our goal was to unearth molecules with heightened efficacy in modulating enzyme activity. A meticulous exploration of a synthesis library, housing around 3000 compounds, expedited the identification of potent candidates. Employing advanced docking studies and field-based Quantitative Structure-Activity Relationship (FB-QSAR) analyses enriched our understanding of the complex interactions between synthesized compounds and COX enzymes. Guided by FB-QSAR insights, our synthesis path led to the identification of compounds 4g, 4h, 4l, and 4k as potent COX-2 inhibitors, surpassing COX-1 efficacy. Conversely, compounds 5b and 5e exhibited heightened inhibitory activity against COX-1 relative to COX-2. The utilization of pyrrole derivatives as COX enzyme inhibitors holds promise for groundbreaking advancements in the domain of anti-inflammatory therapeutics, presenting avenues for innovative pharmaceutical exploration.
ABSTRACT
Alzheimer's disease (AD) is a neurological, progressive illness that typically affects the elderly and is clinically distinguished by memory and cognitive decline. Due to a number of factors, including the absence of a radical treatment, an increase in the patient population over time, the high cost of care and treatment, and a significant decline in patients' quality of life, the importance of this disease has increased. These factors have all prompted increased interest among researchers in this field. The chemical structure of the donepezil molecule, the most popular and effective treatment response for AD, served as the basis for the design and synthesis of 42 novel indan-1-one derivatives in this study. Using IR, 1H, and 13C NMR as well as mass spectroscopic techniques, the compounds' structures were identified. Research on the compounds' antioxidant activities, cholinesterase (ChE) enzyme inhibition, monoamine oxidase (MAO) A and B inhibitory activities, ß-amyloid plaque inhibition, and cytotoxicity impact was carried out. Inhibition of ß-amyloid plaque aggregation; effective inhibition of AChE, BChE, and MAO-B enzymes; and significant antioxidant activity were all demonstrated by compounds D28-D30 and D37-D39. Because of their various actions, it was hypothesized that the related compounds may be useful in treating AD symptoms as well as providing palliative care.
ABSTRACT
Aim: Design of 5-methoxy benzofuran hybrids with 2-carbohydrazide and 2-(1,3,4-oxadiazol-2-yl) as potential inhibitors of monoamine oxidase (MAO)-B targeting Parkinson disease. Materials and methods: 12 compounds were synthesized and analyzed via high-resolution mass spectrometry, 1H nuclear magnetic resonance and 13C nuclear magnetic resonance techniques. In vitro fluorometric assay was used to investigate the activity of the synthesized compounds on both MAO-A and MAO-B isozymes. Results: Three compounds - 3a, 3c and 3e - displayed half maximal inhibitory concentration values of 0.051 ± 0.002, 0.038 ± 0.001 and 0.077 ± 0.003 µM in the inhibition of MAO-A and 0.048 ± 0.002, 0.040 ± 0.001 and 0.072 ± 0.002 µM for MAO-B, respectively. A molecular dynamics simulation study showed that compound 3c has poor stability as a complex with MAO-A. Conclusion: Compound 3c may be a potential candidate for the treatment of Parkinson disease.
Subject(s)
Monoamine Oxidase , Parkinson Disease , Humans , Monoamine Oxidase/metabolism , Monoamine Oxidase Inhibitors/pharmacology , Monoamine Oxidase Inhibitors/chemistry , Parkinson Disease/drug therapy , Molecular Docking Simulation , Mass Spectrometry , Structure-Activity Relationship , Molecular StructureABSTRACT
The use of dual acetylcholinesterase (AChE)-monoamine oxidase B (MAO-B) inhibitors is a new approach in the treatment of Alzheimer disease (AD). In this work, 14 new benzothiazoles (4a-4n) were designed and synthesized. In biological activity studies, the AChE, butyrylcholinesterase (BChE), MAO-A and MAO-B inhibitory potentials of all compounds were evaluated using the in vitro fluorometric method. Additionally, amyloid beta (Aß)-aggregation inhibitory effects of active compounds were evaluated by means of an in vitro kit-based method. The biological evaluation showed that compounds 4a, 4d, 4f, 4h, 4k and 4m displayed significant activity against AChE and MAO-B enzymes. Compound 4f displayed inhibitory activity against AChE and MAO-B enzyme with IC50 values of 23.4 ± 1.1 nM and 40.3 ± 1.7 nM, respectively. It has been revealed that compound 4f may have the potential to inhibit AChE and MAO-B enzymes, as well as the ability to prevent the formation of beta amyloid plaques accumulated in the brains of patients suffering from AD. In silico studies also support the obtained biological activity findings. Compound 4f provided strong interactions with the active site of both enzymes. In particular, the interaction of compound 4f with flavin adenine dinucleotide (FAD) in the MAO-B enzyme active site is a promising and exciting finding.
ABSTRACT
In this study, 15 thiosemicarbazone derivatives were synthesized. Analysis of the obtained compounds was performed by means of 1 H-NMR, 13 C-NMR and high resolution mass spectroscopy (HRMS) spectroscopic methods. The inhibition effect of the obtained compounds on cholinesterase and monoaminoxidase (MAO) enzymes were investigated with in vitro methods. None of the compounds showed significant activity on the butyrylcholinesterase enzyme. On the other hand, compounds 3b, 3c, 3e, 3k, 3l, 3m, 3n and 3o displayed significant activity on acetylcholinesterase (AChE) while compounds 3f, 3i, 3k, 3l, 3m, 3n, 3o also showed remarkable effects on monoamine oxidase-B (MAO-B) enzymes. For the selected compounds, docking studies were performed and the enzyme active site and binding modes were determined. It was revealed that the strongest interaction with AChE and MAO-B enzyme active sites was observed with the compound 3k. Another important factor in the treatment of diseases affecting the central nervous system such as Alzheimer's is the ability of the compounds to cross the blood-brain barrier (BBB). Additionally, the agents planned for the treatment of these diseases must also pass the blood-brain barrier. Therefore, in silico BBB penetration properties of active compounds were investigated.