Combinatorial Chemistry & High Throughput Screening - Volume 20, Issue 6, 2017

Aim and Objective: Depression is a momentous disease that can greatly reduce the quality of life and cause death. In depression, neurotransmitter levels such as serotonine, dopamine and noradrenaline are impaired. Monoamine oxidases (MAO) are responsible for oxidative catalysis of these monoamine neurotransmitters. Because of this relation, MAO-A inhibitors show antidepressant activity by regulating neurotransmitter levels. This study was carried out to investigate the design, synthesis and activity of new antidepressant compounds in pyrazoline and hydrazone structure. Material and Method: Chalcones and hydrazides were heated under reflux to give new pyrazoline and hydrazone derivatives. Docking simulations were performed using AutoDock4.2. hMAO activities were determined by a fluorimetric method. To determine cell viability, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay was used. Behavioral activities of the three compounds were determined by using Forced Swim Test, Step-Through Passive Avoidance Test, Elevated Plus Maze and Open Field Arena Tests. Results: According to in vitro tests, all of the synthesized compounds were found more potent than moclobemide and six of the synthesized compounds were found more selective than moclobemide. Three of the synthesized compounds were investigated for their behavioral activities comparing with moclobemide after 7 days of i.p. treatment at 30 mg/kg. One of the three compounds elicited significant antidepressant properties. Conclusion: All of the synthesized compounds were found potent hMAO-A inhibitors in in vitro screening tests. Only one of the in vivo tested three compounds, (3-(2-hydroxy-5-methylphenyl)-5- p-tolyl-4,5-dihydropyrazol-1-yl)(pyridin-4-yl) methanone indicated significant antidepressant activity. This article opens a window for further development of new pyrazoline and hydrazone derivatives as antidepressant agents.

Background: This is an exciting period for research on monoamine oxidase and its effects on central nervous system. As the current hitting-one-target, therapeutic strategy has become quite inefficient for the treatment of various neurological disorders Objective: The objective of this review is to identify and critically discuss the computational development of multi-target natural and related ligand-MAO protein docking approaches in the study of monoamine oxidase (MAO) enzymes. Discussion: Computational development of the new compounds from natural and related synthetic origin, active as MAO inhibitors (MAOIs) was discussed in some detail. The docking studies related to the alkaloids and their various categories secondary metabolites from plants like alkaloids, flavonoids and xanthones class of compounds specially caffeine, β-carboline, naphthoquinone, morpholine, piperine, amphetamine and furthermore curcumin, eugenol, trans-Farnesol and many other extracted plant constituents with their docking studies were discussed in detail. Conclusion: It is apparent that, by this computational docking approach, more selective, reversible and potent molecules could be proposed as MAO inhibitors by precise modifications on the basic scaffold.

Background Due to the limited number of MAO inhibitors in the clinics, several research efforts are aimed at the discovery of novel MAO inhibitors. At present, a high specificity and a reversible mode of inhibition of MAO-A/B are cited as desirable traits in drug discovery process. This will help to reduce the probability of causing target disruption and may increase the duration of action of drug. Aim: Most of the existing MAO inhibitors lead to side effects due to the lack of affinity and selectivity. Therefore, there is an urgent need to design novel, potent, reversible and selective inhibitors for MAO-A/B. Selective inhibition of MAO-A results in the elevated level of serotonin and noradrenaline. Hence, MAO-A inhibitors can be used for improving the symptoms of depression. The selective MAO-B inhibitors are used with L-DOPA and/or dopamine agonists in the symptomatic treatment of Parkinson's disease. The present study was aimed to describe the recently developed hits of MAO inhibitors. Method: At present, CADD techniques are gaining an attention in rationale drug discovery of MAO inhibitors, and several research groups employed CADD approaches on various chemical scaffolds to identify novel MAO inhibitors. These computational techniques assisted in the development of lead molecules with improved pharmacodynamics / pharmacokinetic properties toward MAOs. Further, CADD techniques provided a better understanding of structural aspects of molecular targets and lead molecules. Conclusions: The present review describes the importance of structural features of potential chemical scaffolds as well as the role of computational approaches like ligand docking, molecular dynamics, QSAR and pharmacophore modeling in the development of novel MAO inhibitors.

Aim and Objective: MAO inhibitors have a significant effect on the nervous system since they act in regulation of neurotransmitter concentrations. Neurotransmitter levels are critical for a healthy nervous system. MAO inhibitors can be used in the treatment of neurological disorders such as depression, Parkinson's disease and Alzheimer's disease, as the increase or decrease of some neurotransmitter concentrations is associated with these neurological disorders. This study was conducted to discover new and active MAO inhibitor drug candidates. Materials and Methods: New pyrazoline derivatives have been designed with the molecular docking approach and interactions of our compounds with the MAO enzyme have been investigated using the Autodock 4.2 program. The designed pyrazoline derivative compounds were synthesized by the reaction of the chalcones and hydrazides in ethanol. hMAO inhibitory activities of the newly synthesized compounds were investigated by fluorimetric method. In vitro cytotoxicity of five most potent inhibitors were tested in HepG2 cells. Results: (3-(5-bromo-2-hydroxyphenyl)-5-(4-methoxyphenyl)-4,5-dihydropyrazol-1-yl)(phenyl) methanone (5i) and (3-(2-hydroxy-4-methoxy phenyl)-5-p-tolyl-4,5-dihydropyrazol-1-yl)(phenyl) methanone (5l) inhibited hMAO-A more potently than moclobemide (Ki values are 0.004±0.001 and 0.005±0.001, respectively). The same two compounds, 5i and 5l, inhibited hMAO-A more selectively than moclobemide (SI values are 5.55x10-5 and 0.003, respectively). Both of these compounds were found non toxic at 1 μM, 5 μM and 25μM concentrations. Conclusion: Two of the newly synthesized compounds, (3-(5-bromo-2-hydroxyphenyl)-5-(4- methoxyphenyl)-4,5-dihydropyrazol-1-yl)(phenyl)methanone and (3-(2-hydroxy-4-methoxy phenyl)- 5-p-tolyl-4,5-dihydropyrazol-1-yl)(phenyl) methanone were found to be promising MAO-A inhibitors due to their high inhibitory potency, high selectivity and low toxicity.

Aim and Objective: Specific inhibitors of monoamine oxidase (MAO)-B are considered useful therapeutic agents in targeting neurological disorders like Alzheimer's and Parkinson's diseases. Due to the academic challenge of designing new hMAO-B inhibitors and the possibility of discovering compounds with improved properties compared to existing MAO-B inhibitors, a number of research groups are searching for new classes of chemical compounds that may act as selective hMAO-B inhibitors. Materials and Methods: Among these, chromone (4H-1-benzopyran-4-one) derivatives have recently emerged as a chemotype with specific and high potency MAO-B inhibition. Chromones are structurally related to a series of coumarins and chalcones, which are well-known inhibitors of MAO-B. Results: The experimental evidence has demonstrated that most of the chromone skeleton derived compounds have shown potent, reversible and selective type of hMAO-B inhibitors. Conclusion: The current review focuses on the MAO-B inhibitory properties of various synthetically derived chromones with specific emphasis on the structure-activity relationships and molecular recognition of MAO-B inhibition by this class. This review covers the recent updates present in the literature and will certainly provide a greater insight for the design and development of new class of potent chromone based selective MAO-B inhibitors.

Aim and Objective: Korea advanced institute of science and technology cubic ordered mesoporous silica (KIT-6 mesoporous) silica coated magnetite nanoparticles, is an effective, ecobenign and recyclable catalyst for the electrophilic substitution reactions of indoles with various synthetized aldehydes to afford the corresponding novel diindolylmethanes in high yields and short reaction times. The catalyst can be recovered and reused without loss of activity. The work-up of the reaction consists of a simple separation, followed by concentration of the crude product and purification. The present methodology offers several advantages such as aqueous media, excellent yields, simple procedure, mild conditions and reduced environmental consequences. All of synthesized compounds are new and were characterized by IR, NMR and elemental analyses. Materials and Methods: A mixture of synthetized pyrazolecarbaldehydes [24] (2.0mmol), indole (4.0mmol) and Fe3O4@SiO2@KIT-6 (0.04mmol) and H2O (10mL) were stirred at room temperature for the required reaction time according to Table 2. After completion of the reaction, the product was solved in CHCl3 (30 mL) and insoluble catalyst was removed by filtration in the presence of an efficient magnetic bar. The organic phase including the product and CHCl3 was evaporated under vacuum. The resulting crude material was purified by recrystallization from EtOH to afford pure products. Results: As part of our on interest for the development of efficient and environmentally friendly procedures for the synthesis of heterocyclic and pharmaceutical compounds, an efficient, facile and aqueous media was introduced for the synthesis of novel derivatives of diindolylmethanes containing pyrazole moiety. A variety of synthetized aldehyde compounds reacted smoothly with indoles to produce diindolylmethanes under these reaction conditions. The electron deficiency and the nature of the substituents on the aromatic ring show some effects on this conversion. All the reactions were run with catalytic amounts of catalysts. The best results gained with 0.04mmol of Fe3O4@@SiO2@KIT-6 as a strong Lewis acid at room temperature in aqueous media. Conclusion: In conclusion, we have investigated the synthesized KIT-6 mesoporous silica coated magnetite nanoparticles (MMNPs) as a mild and efficient catalyst for the synthesis of novel diindolylmethanes coupled with pyrazole moiety in aqua media. The simplicity, easy workup together with the use of inexpensive, environmentally friendly and reusable catalyst, is the notable features of this catalytic procedure. To the best of our knowledge, this is the first report for the synthesis of a new library of diindolylmethane compound bearing pyrazole moiety that enhance the biological and pharmacological activity.

Background: Mammary tumors are the second most common tumors (after skin tumors) in female dogs (Canis lupus familiaris). Tissue Inhibitor of Metlloproteinases-3 (TIMP-3) is a matrix associated endogenous inhibitor of Matrix Metalloproteinases (MMPs). Cancer metastasis occurs as a result of imbalance between MMPs and TIMPs. TIMP-3 is involved significantly in regulation of MMPs as well as progression of canine mammary tumor. Objective: The present study was conducted to identify the structural and functional relationship between TIMP-3 and MMP which can aid in identifying the role of these proteins in canine mammary tumor. Methods: Molecular characterization of TIMP-3 protein was done by molecular biology techniques such as gene cloning and sequencing. The homology based model of TIMP-3 protein was created and verified with a variety of available computational techniques as well as molecular dynamics simulation. Results: The results indicated that predicted TIMP-3 protein structure of Canis lupus familiaris was reliable and more stable. The docking of TIMP-3 protein with MMP-2 and MMP-9 represents conformational structure of these two proteins which interact with each other but if misled canresult in the progression of tumor in canine. Conclusions: The three dimensional structure of TIMP-3 was generated and its interactions with MMP-2 and MMP-9, demonstrates the role of key binding residues. Until now, no structural details were available for canine TIMP-3 proteins, hence this study will broaden the horizon towards understanding the structural and functional aspects of this proteins in canine.

Aim and Objective: Plasmodium knowlesi has been recently recognized as a human malarial parasite, particularly in the region of south-east Asia. Unlike human host, P. knowlesi cannot salvage pyrimidine bases and relies solely on nucleotides synthesized from de novo pyrimidine pathway. The enzymes involved in this are also unique in terms of their structure and function to its human counterpart. Thus, targeting Dihydroorotase, an enzyme involved in the pyrimidine biosynthesis, provides a promising route for novel drug development. Materials and Methods: The 3D structure of P. knowlesi Dihydroorotase was predicted, refined and validated. Multiple docking was performed and the resultant complex was used for 3D structurebased pharmacophore modelling. A combinatorial library of 2,664,779 molecules was generated and used for structure based virtual screening. The stability of resultant compounds was checked using simulation studies. Results: The modelled 3D structure of P. knowlesi Dihydroorotase enzyme is relaxed by running an MD simulation of 20 ns, and structure is validated by using Ramachandran plot and G-factor analysis. A five point based pharmacophore model was created and used as a query for screening in house database. The stability of two negatively charged compounds was studied, and ZINC22066495-DHOase complex was more stable throughout the simulation. Conclusion: The present study shows that ZINC22066495 compound has a high potential for disrupting P. knowlesi DHOase enzyme and may be used as a potential lead molecule for effective pyrimidine biosynthesis inhibition in P. knowlesi.

Aim and Objective: Due to the common ethnopharmacological used or scientifically examined biochemical properties, Elaeagnaceae family, Elaeagnus umbellate (Thunb.) (EU, Guz yemisi) was worth investigating. Materials and Methods: In this investigation, we revealed antioxidant, antiproliferative and enzyme inhibition activities of the water, methanol, ethanol, acetone, ethyl acetate and hexane extracts of EU as well as the contents of their phenolic, flavonoid, anthocyanin, ascorbic acid, lycopene and β-carotene. The antioxidant activity was screened by total antioxidant (phosphomolybdenum), inhibition of linoleic acid peroxidation, reducing power, 2-deoxyribose degradation assay, H2O2 scavenging and metal chelating activities of the samples were tested in vitro. Additionally, the scavenging activities of the extracts were determined against 1,1-diphenyl-2-picrylhydrazyl (DPPH#153;), 2,2-azino-bis(3-ethylbenzothiazloine-6-sulfonicacid (ABTS^.+), superoxide anion and peroxide radicals. The samples were determined for their inhibitory activities against urease, acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). In vitro, antiproliferative activities of six different extracts were tested using the xCELLigence system against HeLa and HT29 cell lines. Results: The antioxidant activities of the extracts were found higher than standard antioxidants. The water extracts of fruit and leaf showed the best antioxidant activity. In inhibition assays of urease, AChE and BuChE, all extracts exhibited remarkable inhibition potential. Ethyl acetate extracts, especially, showed better inhibition capacity. It was found that the antioxidant activities of the extracts presented consistently with their chemical contents. The antiproliferative activities of leaf extracts were more effective than the fruit extracts. The chromatographic methods were applied to the different solvents to analyses phenolic secondery metabolites. It was found that fumaric acid, 4- hydroxybenzoic acid, rutin and quercetin-3-β-D-glucoside, neohesperidin, hesperidin determined to have higher contents all the extracts. Conclusion: EU can be suggested as a potential natural source of antioxidants appropriate for utilization in nutritional/pharmaceutical fields.