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1.
Brain Sci ; 14(6)2024 Jun 04.
Article in English | MEDLINE | ID: mdl-38928574

ABSTRACT

Tobacco and alcohol have been identified as health risk behaviors associated with significant unfavorable health consequences, ranking within the list of the top ten causes of mortality and disability-adjusted life years (DALY). The combustion of tobacco leads to the formation of acrylamide (ACR), which is well known for its neurotoxic effects. Similarly, alcohol consumption has also been widely recognized for its neurotoxic effects. Both substances can affect neurons and neuroglia cells through various pathways. This study sought to examine the impacts of co-administration of ACR and intermittent-access ethanol (IAE) consumption over a period of one month. The experimental group received 20 mg/kg of ACR, administered orally, along with IAE of 20% ethanol sessions lasting 24 h, three times per week. The cognitive outcomes were assessed utilizing the elevated plus maze (EPM), which was employed as a means of assessing the capability to learn and remember, the novel object recognition (NOR) test, which was employed to assess recognition memory, and the Y-maze, which was used to explore a new environment and navigate. Additionally, ELISA assays were performed to examine underlying mechanisms, including markers associated with inflammation (NF-κB, PGE2, and TNF-α), apoptosis (Bcl2, Bax, and Caspase-3), and oxidative stress (MDA, catalase, and GSH). These markers were assessed in the brain homogenate as part of the investigation. Furthermore, a histopathological study was conducted. The findings indicated that NF-κB levels increased significantly in the combination of ACR and IAE groups (ACR + IAE) compared to either the ACR-alone or IAE-alone groups. However, parallel changes were observed in TNF-α, PGE2, Bax, Bcl-2, Caspase-3, GSH, and CAT levels when comparing the ACR + IAE group to the ACR-alone group. Comparable alterations were noted between the ACR + IAE treatment and IAE-alone groups in TNF-α, Bcl-2, MDA, GSH, and CAT levels. Moreover, the histopathological analysis revealed significant changes between the ACR + IAE and the ACR- or IAE-alone groups. Regarding memory parameters assessed using tests including EPM, NOR, and Y-maze, considerable changes were observed across all treatment groups as opposed to the control. Surprisingly, there were no notable differences in the NOR and Y-maze tasks between the alone and combination treatment. Further study is necessary to explore the long-term alteration of co-administering ACR and IAE on behavior, memory, and neurotoxicity-related mechanisms, in order to elucidate their combined effects more clearly.

2.
Plants (Basel) ; 12(4)2023 Feb 18.
Article in English | MEDLINE | ID: mdl-36840284

ABSTRACT

Islamic literature has indicated that daily consumption of Ajwa dates heals a variety of chronic diseases and disorders. The current research investigates the neuroprotective effect of methanolic Ajwa seed extract (MASE) on lipopolysaccharide (LPS)-induced cognitive deficits using multiple approaches. For animal studies, MASE (200 and 400 mg/kg, p.o.) was administrated for thirty consecutive days, and four doses of LPS (250 µg/kg, i.p.) were injected to induce neurotoxicity. Memory functions were evaluated using elevated plus-maze and novel object recognition tests. Acetylcholine (ACh) and neuroinflammatory markers (cyclooxygenase (COX)-2, tumor necrosis factor (TNF)-α, interleukin (IL)-6, IL-10, and transforming growth factor (TGF)-ß1) were estimated in brain tissues. Studies of molecular docking and dynamics were conducted to provide insight into the molecular-level mechanisms. MASE administration resulted in a significant reversal of LPS-induced memory impairment in both maze models. Both doses of MASE elevated the ACh levels in an LPS-treated rat brain. In addition, the extract lowered COX-2 and proinflammatory cytokines (TNF-α and IL-6) while increasing anti-inflammatory cytokines (IL-10 and TGF-ß1) in LPS-treated brain tissues. Molecular modeling results revealed that the compound's ellagic acid, epicatechin, catechin, kaempferol, quercetin, and apigenin have the potential to act as a dual inhibitor of acetylcholinesterase (AChE) and COX-2 and can be responsible for the improvement of both cholinergic and inflammatory conditions, while the cinnamic acid, hesperidin, hesperetin, narengin, and rutin compounds are responsible only for the improvement of cholinergic transmission. The above compounds acted by interacting with the key residues Trp84, Asp72, Gly118, Ser200, Tyr334, and His440, which are responsible for the hydrolysis of ACh in AChE, while the COX-2 is inhibited by interacting with the residues (Val349, Leu352, Tyr355, Tyr385, Ala527, Ser530, and Leu531) of the hydrophobic channel. By promoting cholinergic activity and protecting neuroinflammation in the rat brain, MASE provides neuroprotection against LPS-induced cognitive deficits. Our preliminary findings will help with further drug discovery processes related to neuroinflammation-related neurodegeneration.

3.
Pharmaceuticals (Basel) ; 15(12)2022 Dec 14.
Article in English | MEDLINE | ID: mdl-36559014

ABSTRACT

Cancer chemotherapy is known to cause cognitive defects in patients. Our study investigated the effect of piracetam (PIRA; 200 or 400 mg/kg) against doxorubicin (DOX)-induced cognitive deficits in a rat model. The cognitive parameters were analyzed using elevated plus-maze, novel object recognition, and Y-maze tests. Acetylcholinesterase (AChE), neuroinflammatory mediators (cyclooxygenase-2 (COX-2), prostaglandin E2 (PGE2), nuclear factor-κB (NF-κB), tumor necrosis factor-alpha (TNF-α)), apoptotic proteins (B-cell lymphoma-2 (Bcl-2), Bcl2 associated X protein (Bax), cysteine aspartate specific protease-3 (caspase-3)), oxidative parameters (malondialdehyde (MDA), catalase (CAT), and glutathione (GSH)) were also determined in the brain. PIRA administration offered significant protection against DOX-induced cognitive deficits in all maze tests and restored cholinergic functions via a significant reduction in AChE levels. Additionally, PIRA suppressed DOX-induced neuroinflammatory mediators (COX-2, PGE2, NF-κB, and TNF-α), pro-apoptotic proteins (Bax and caspase-3), and oxidative stress (MDA). Besides, it facilitated antioxidant (CAT and GSH) levels. Hence, our study highlighted that the neuroprotective activity of PIRA against DOX-induced cognitive deficits can be linked to reductions of AChE levels, neuro-inflammatory mediators, pro-apoptotic proteins, and oxidative stress.

4.
Molecules ; 27(21)2022 Oct 29.
Article in English | MEDLINE | ID: mdl-36364190

ABSTRACT

Cancer chemotherapy-induced cognitive impairment (chemobrain) is a major complication that affects the prognosis of therapy. Our study evaluates the nootropic-like activity of levetiracetam (LEVE) against doxorubicin (DOX)-induced memory defects using in vivo and molecular modelling. Rats were treated with LEVE (100 and 200 mg/kg, 30 days) and chemobrain was induced by four doses of DOX (2 mg/kg, i.p.). Spatial memory parameters were evaluated using an elevated plus maze (EPM) and Y-maze. Additionally, acetylcholinesterase (AChE) and the neuroinflammatory biomarkers cyclooxygenase-2 (COX-2), prostaglandin E2 (PGE2), nuclear factor-κB (NF-κB), and tumor necrosis factor-alpha (TNF-α) were analyzed using brain homogenate. PharmMapper was used for inverse docking and AutoDock Vina was used for molecular docking. LEVE treatment significantly diminished the DOX-induced memory impairment parameters in both the EPM and Y-maze. In addition, the drug treatment significantly reduced AChE, COX-2, PGE2, NF-κB, and TNF-α levels compared to DOX-treated animals. The inverse docking procedures resulted in the identification of AChE as the potential target. Further molecular modelling studies displayed interactions with residues Gly118, Gly119, and Ser200, critical for the hydrolysis of ACh. Analysis of the results suggested that administration of LEVE improved memory-related parameters in DOX-induced animals. The 'nootropic-like' activity could be related to diminished AChE and neuroinflammatory mediator levels.


Subject(s)
Chemotherapy-Related Cognitive Impairment , Nootropic Agents , Animals , Rats , Molecular Docking Simulation , Nootropic Agents/pharmacology , Levetiracetam/pharmacology , Acetylcholinesterase/metabolism , Tumor Necrosis Factor-alpha/pharmacology , NF-kappa B/pharmacology , Cyclooxygenase 2 , Neuroinflammatory Diseases , Dinoprostone , Doxorubicin/adverse effects , Cholinergic Agents/pharmacology , Oxidative Stress
5.
Saudi Pharm J ; 30(6): 750-763, 2022 Jun.
Article in English | MEDLINE | ID: mdl-35812141

ABSTRACT

Cognitive decline is one of the serious complications associated with diabetes mellitus (T2DM) of type-2. In this reported work, the effect of aqueous sukkari dates seed extract (ASSE) was evaluated in T2DM-induced rats. T2DM was induced using intraperitoneal injection of nicotinamide and streptozocin (STZ) administration. The diabetic rats were then treated orally with 200 mg/kg and 400 mg/kg of dates seed extract for 30 days and results were compared with metformin-treated groups. The memory functions were assessed using three maze models. Glucose and insulin levels in the blood and acetylcholine, acetylcholinesterase brain homogenates were estimated. The results showed a significant reduction in transfer latency (TL) (p < 0.001) during the elevated plus maze (EPM) test. The novel object recognition (NOR) test revealed a longer exploration time (p > 0.05) with novel objects and a higher discrimination index (p > 0.05). The Y-maze test also showed a significant increase in the number of entries to the novel arm (p > 0.05) and the total number of entries in the trial (p > 0.01) as well as in test (p > 0.05) sessions. Reduction in blood glucose (p > 0.05) and improvement in blood insulin (p > 0.05) levels were also noted. Improvement in ACh levels (p > 0.001) with 400 mg/kg of ASSE and reduction in AChE (p > 0.001) with both doses of ASSE were also observed in the brain homogenates. The results of ASSE were found comparable with the metformin-treated rats. The estimation of phytochemical constituents displayed a significant presence of phenolic content. Further, molecular modeling studies showed ellagic acid, catechin, and epicatechin as the potential molecule interacting with GSK-3ß, α-amylase, and AChE and may be responsible for observed bioactivity. In conclusion, ASSE has the ability to alleviate T2DM-related cognitive impairments.

6.
Saudi J Biol Sci ; 29(4): 2738-2748, 2022 Apr.
Article in English | MEDLINE | ID: mdl-35531250

ABSTRACT

Diabetes is a metabolic disorder prevalent across the globe and is known to cause brain dysfunction, especially memory and cognitive decline. The current study investigates the effect of aqueous Ajwa seeds extract (AASE) on type-2 diabetes mellitus (T2DM)-induced memory deficits using a rat model. T2DM was induced by an administration of nicotinamide (120 mg/kg, i.p.) and streptozotocin (STZ) (60 mg/kg, i.p.). AASE (200 and 400 mg/kg, p.o.) were treated to T2DM rats for 30 days and the results were compared with the metformin (200 mg/kg). Elevated plus maze (EPM), Y-maze, and novel object recognition (NOR) tests were performed to assess the memory functions. The blood glucose and plasma insulin levels were estimated to assess the anti-diabetic effects of AASE. Acetylcholine (ACh) and acetylcholinesterase (AChE) levels were estimated from brain homogenates to assess cholinergic transmission. Treatment with AASE resulted in the reversal of behavioral deficits. EPM showed, a significant reduction in transfer latency (TL) among T2DM rats. High exploration time with a novel object and improvement in discrimination index were observed among treated groups during the NOR test. The Y-Maze test improved the entries and also time spent in the novel arm. Moreover, treatment of AASE reversed hyperglycemic and enhanced plasma insulin levels (200 mg/kg: 3.81 ± 0.08 ng/ml and 400 mg/kg: 4.09 ± 0.10 ng/ml) among T2DM rats (2.81 ± 0.15 ng/ml). Improved ACh levels (200 mg/kg: 186.6 ± 9.51 pg/mg protein and 400 mg/kg: 165.5 ± 9.25 pg/mg protein) and reduced AChE levels (200 mg/kg: 0.29 ± 0.02 ng/mg protein and 400 mg/kg: 0.32 ± 0.03 ng/mg protein) were also noted in the brain of AASE treated groups as referred to diabetic group (ACh: 107.1 ± 7.16 pg/mg protein and AChE: 0.51 ± 0.03 ng/mg protein). The above results were found to be comparable with the metformin-treated groups. From the results, it can be concluded that AASE has the potential to improve T2DM associated cognitive deficits.

7.
Brain Sci ; 11(12)2021 Dec 08.
Article in English | MEDLINE | ID: mdl-34942919

ABSTRACT

Clobenpropit (CLO), an antagonist on histamine H3 receptors (HH3R), has been shown to protect NMDA-induced neuronal necrosis in cortical neuronal cell culture from rats. In this work, we explored its potential on lipopolysaccharide (LPS)-induced memory deficits, neuroinflammation, and mitochondrial dysfunction in mice. CLO (1 and 3 mg/kg, p.o.) was treated continually for 30 days, and neurotoxicity was induced by four doses of LPS (250 µg/kg, i.p.). The radial arm maze (RAM) was used to access memory behaviors. After the REM test, brain tissue was collected from each mouse to estimate pro-inflammatory cytokines (TNFα and IL6), anti-inflammatory cytokines (TGF-ß1 and IL-10), cyclooxygenase-2 (COX 2), and mitochondrial respiratory chain complex (MRCC- I, II and IV) enzymes. CLO treatment reversed the LPS-induced behavioral deficits by a significant reduction in time taken to consume all five bites (TTB), working memory error (WME), and reference memory error (REM) in the REM test. Regarding neuroinflammation, it attenuated the release of COX, TNF-α, and IL-6, and augmented TGF-ß1 and IL-10 levels in the brain. Reversal of LPS-induced brain MRCC (I, II, and IV) levels also resulted with CLO treatment. From these findings, CLO promises neuroprotection against LPS-induced cognitive deficits by ameliorating neuroinflammation and restoring the MRCC enzymes in mice.

8.
J Comput Chem ; 2020 Sep 10.
Article in English | MEDLINE | ID: mdl-32964506

ABSTRACT

Nitreones are compounds with oxidation state 1 at the nitrogen, these compounds carry formal positive charge as well as two lone pairs of electrons at nitrogen center. These compounds are also known as divalent NI compounds and can be represented with the general formula L → N+ ← L, where L is an electron donating ligand. In the recent past, several divalent NI compounds have been reported with L = N-heterocyclic carbene (NHC), remote N-heterocyclic carbene (rNHC), carbocyclic carbene (CCC) and diaminocarbene. Recently, our group reported that a novel six-membered CCC (cyclohexa-2,5-diene-4-[diaminomethynyl]-1-ylidene) can stabilize N+ center in nitreones. As an independent carbene, this species is very unstable. In this work, modulation of this CCC using (a) annulation, (b) heterocyclic ring modification, (c) substitutions adjacent to the carbenic carbon, (d) exocyclic double bond insertion and (e) ring contraction, has been reported. These modulations and quantum chemical analyses helped in the identification of five new six-membered CCCs which carry improved donation and stability properties. Further, these CCCs were employed in the design of new divalent NI compounds (nitreones) which carry coordination bonds between ligands and N+ center. The molecular and electronic structure properties, and the donor→acceptor coordination interactions present in the resultant low oxidation state divalent NI compounds have been explored.

9.
Bioorg Chem ; 96: 103581, 2020 03.
Article in English | MEDLINE | ID: mdl-31978686

ABSTRACT

Dihydropyridine derivatives 1-31 were synthesized via one-pot solvent free condition and screened for in vitro against α-amylase and α-glucosidase enzyme. The synthetic derivatives 1-31 showed good α-amylase inhibition in the range of IC50 = 2.21 ± 0.06-9.97 ± 0.08 µM, as compared to the standard drug acarbose (IC50 = 2.01 ± 0.1 µM) and α-glucosidase inhibition in the range of IC50 = 2.31 ± 0.09-9.9 ± 0.1 µM as compared to standard acarbose (IC50 = 2.07 ± 0.1 µM), respectively. To determine the mode of binding interactions of synthetic molecules with active sites of enzyme, molecular docking studies were also performed. Different spectroscopic techniques such as 1H, 13C NMR, EI-MS, and HREI-MS were used to characterize all the synthetic compounds.


Subject(s)
Dihydropyridines/chemical synthesis , Dihydropyridines/pharmacology , Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/pharmacology , Glycoside Hydrolase Inhibitors/chemical synthesis , Glycoside Hydrolase Inhibitors/pharmacology , alpha-Amylases/antagonists & inhibitors , Computer Simulation , Dihydropyridines/chemistry , Enzyme Inhibitors/chemistry , Glycoside Hydrolase Inhibitors/chemistry , In Vitro Techniques , Spectrum Analysis/methods , Structure-Activity Relationship
10.
Bioorg Chem ; 91: 103094, 2019 10.
Article in English | MEDLINE | ID: mdl-31376783

ABSTRACT

Guanylthiourea (GTU) has been identified as an important antifolate antimalarial pharmacophore unit, whereas, 4-amino quinolones are already known for antimalarial activity. In the present work molecules carrying 4-aminoquinoline and GTU moiety have been designed using molecular docking analysis with PfDHFR enzyme and heme unit. The docking results indicated that the necessary interactions (Asp54 and Ile14) and docking score (-9.63 to -7.36 kcal/mmol) were comparable to WR99210 (-9.89 kcal/mol). From these results nine molecules were selected for synthesis. In vitro analysis of these synthesized compounds reveal that out of the nine molecules, eight show antimalarial activity in the range of 0.61-7.55 µM for PfD6 strain and 0.43-8.04 µM for PfW2 strain. Further, molecular dynamics simulations were performed on the most active molecule to establish comparative binding interactions of these compounds and reference ligand with Plasmodium falciparum dihydrofolate reductase (PfDHFR).


Subject(s)
Aminoquinolines/pharmacology , Antimalarials/pharmacology , Drug Design , Guanylthiourea/pharmacology , Plasmodium falciparum/drug effects , Aminoquinolines/chemistry , Antimalarials/chemical synthesis , Antimalarials/chemistry , Dose-Response Relationship, Drug , Guanylthiourea/chemistry , Models, Molecular , Molecular Structure , Parasitic Sensitivity Tests , Structure-Activity Relationship
11.
J Comput Chem ; 2018 Dec 14.
Article in English | MEDLINE | ID: mdl-30549074

ABSTRACT

Carbocyclic carbenes (CCCs) are a class of nucleophilic carbenes which are very similar to N-heterocyclic carbenes (NHCs) in terms of their reactivity, but they do not contain a stabilizing heteroatom in their cyclic ring system. In this study, 17 representative known CCCs and 34 newly designed CCCs are evaluated using quantum chemical methods, and the results are compared in terms of their stability, nucleophilicity, and proton affinity (PA) parameters. The results are divided on the basis of ring size of the known and reported CCCs. The stability, nucleophilicity, PA, complexation energy, and bond strength-related parameters were estimated using M06/6-311++G(d,p) method. The results indicated that the CCCs known in the literature are strong σ-electron donating species and have considerable π-accepting properties. This study led to the design and identification of a few new CCCs with dimethylamine and diaminomethynyl substituents which can be singlet stable and are substantially nucleophilic. © 2018 Wiley Periodicals, Inc.

12.
Chemistry ; 24(24): 6418-6425, 2018 Apr 25.
Article in English | MEDLINE | ID: mdl-29504658

ABSTRACT

Remote N-heterocyclic carbenes (rNHCs), such as N-methyl-4-pyridylidene, are known to form coordination complexes with TMs. Herein, it is established that rNHCs can also coordinate to the N+ centre. Synthesis of some novel divalent NI complexes with the general formula (rNHC)→N+ ←(NHC) and (rNHC)→N+ ←(rNHC) was achieved, and X-ray diffraction studies supported the coordination bond character between the rNHCs and the N+ centre. Quantum chemical analysis established the presence of divalent NI character at the central nitrogen in these systems.

13.
Eur J Med Chem ; 135: 339-348, 2017 Jul 28.
Article in English | MEDLINE | ID: mdl-28460309

ABSTRACT

Guanylthiourea (GTU) derivatives were identified as possible anti-malarial agents, recently, using in vitro studies on Plasmodium falciparum. This article gives an account of the in vivo anti-malarial activity of GTU derivatives against experimental rodent malaria. A total of 20 synthesized GTU derivatives were evaluated for in vivo antimalarial activity, out of which six showed encouraging results; one compound appeared to have curative potential. Molecular docking and molecular dynamics analysis were carried out to understand the molecular level interactions.


Subject(s)
Antimalarials/pharmacology , Guanylthiourea/pharmacology , Malaria/drug therapy , Plasmodium falciparum/drug effects , Antimalarials/chemical synthesis , Antimalarials/chemistry , Dose-Response Relationship, Drug , Guanylthiourea/chemical synthesis , Guanylthiourea/chemistry , Models, Molecular , Molecular Structure , Parasitic Sensitivity Tests , Structure-Activity Relationship
14.
Eur J Med Chem ; 121: 727-736, 2016 Oct 04.
Article in English | MEDLINE | ID: mdl-27423119

ABSTRACT

In this work, iminothiazolidin-4-one derivatives were explored as selective GSK-3ß inhibitors. Molecular docking analysis was carried to design a series of compounds, which were synthesized using substituted thiourea, 2-bromoacetophenones and benzaldehydes. Out of the twenty five compounds synthesized during this work, the in vitro evaluation against GSK-3 led to the identification of nine compounds with activity in lower nano-molar range (2-85 nM). Further, in vitro evaluation against CDK-2 showed five compounds to be selective towards GSK-3.


Subject(s)
Drug Design , Glycogen Synthase Kinase 3 beta/antagonists & inhibitors , Protein Kinase Inhibitors/chemical synthesis , Protein Kinase Inhibitors/pharmacology , Thiazolidines/chemical synthesis , Thiazolidines/pharmacology , Adenosine Triphosphate/metabolism , Binding, Competitive , Chemistry Techniques, Synthetic , Glycogen Synthase Kinase 3 beta/chemistry , Glycogen Synthase Kinase 3 beta/metabolism , Humans , Molecular Docking Simulation , Molecular Dynamics Simulation , Protein Conformation , Protein Kinase Inhibitors/chemistry , Protein Kinase Inhibitors/metabolism , Structure-Activity Relationship , Thiazolidines/chemistry , Thiazolidines/metabolism
15.
J Org Chem ; 81(12): 5120-7, 2016 06 17.
Article in English | MEDLINE | ID: mdl-27182931

ABSTRACT

An efficient, metal and base-free, chemoselective synthesis of aryl-, heteroaryl-, and alkyl primary amines from the corresponding boronic acids has been achieved at ambient temperature mediated by [bis(trifluoroacetoxy)iodo]benzene (PIFA) and N-bromosuccinimide (NBS) using cyanamidyl/arylcyanamidyl radicals as the aminating species. The primary amine compounds were initially obtained as their corresponding ammonium trifluoroacetate salts which, on treatment with aq NaOH, provide the free amines. Finally, the primary amines were isolated through column chromatography over silica-gel using hexane-EtOAc solvent system as the eluent. The reactions are sufficiently fast, completing within 1 h. Quantum chemical calculations in combination with experimental observations validate that the ipso amination of substituted boronic acids involves the formation of cyanamidyl/arylcyanamidyl radical, followed by regiospecific interaction of its nitrile-N center with boron atom of the boronic acids, leading to chemoselective primary amination.

16.
Chemistry ; 22(3): 1088-96, 2016 Jan 18.
Article in English | MEDLINE | ID: mdl-26615987

ABSTRACT

The dative-bond representation (L→E) in compounds with main group elements (E) has triggered extensive debate in the recent past. The scope and limits of this nonclassical coordination bond warrant comprehensive exploration. Particularly compounds with (L→N←L')(+) arrangement are of special interest because of their therapeutic importance. This work reports the design and synthesis of novel chemical species with the general structural formula (L→N←L')(+) carrying the unusual ligand cyclohexa-2,5-diene-4-(diaminomethynyl)-1-ylidene. Four species belonging to the (L→N←L')(+) class carrying this unconventional ligand were synthesized. Quantum chemical and X-ray diffraction analyses showed that the electronic and geometric parameters are consistent with those of already reported divalent N(I) compounds. The molecular orbital analysis, geometric parameters, and spectral data clearly support the L→N and N←L' interactions in these species. The newly identified ligand has the properties of a reactive carbene and high nucleophilicity.

17.
J Biomol Struct Dyn ; 33(12): 2578-93, 2015.
Article in English | MEDLINE | ID: mdl-26209183

ABSTRACT

Glycogen synthase kinase-3 is a constitutively acting, multifunctional serine threonine kinase, the role of which has been implicated in several physiological pathways and has emerged as a promising target for the treatment of type-II diabetes and Alzheimer's disease. In order to provide a detailed understanding of the origin of selectivity determinants of ATP competitive inhibitors, molecular dynamics simulations in combination with MM-PBSA binding energy calculations were performed using crystal structures of GSK-3ß and CDK-2 in complex with 12 ATP competitive inhibitors. Analysis of energy contributions indicate that electrostatic interaction energy dictates the selectivity of ATP competitive inhibitors against CDK-2. Key interactions as well as residues that potentially make a major contribution to the binding free energy were identified at the ATP binding site. This analysis stresses the need for the inhibitors to interact with Lys85, Thr138, and Arg141 in the binding site of GSK-3ß to show selectivity. The residue-wise energy decomposition analysis further suggested the additional role of Gln185 in determining the selectivity of maleimides. The results obtained in this study can be utilized to design new selective GSK-3 ATP competitive inhibitors.


Subject(s)
Adenosine Triphosphate/chemistry , Glycogen Synthase Kinase 3/chemistry , Molecular Dynamics Simulation , Protein Kinase Inhibitors/chemistry , Adenosine Triphosphate/metabolism , Algorithms , Binding Sites , Binding, Competitive , Glycogen Synthase Kinase 3/antagonists & inhibitors , Glycogen Synthase Kinase 3/metabolism , Glycogen Synthase Kinase 3 beta , Humans , Hydrogen Bonding , Ligands , Molecular Structure , Protein Kinase Inhibitors/metabolism , Protein Kinase Inhibitors/pharmacology , Protein Structure, Tertiary , Static Electricity , Thermodynamics
18.
J Comput Chem ; 35(28): 2047-55, 2014 Oct 30.
Article in English | MEDLINE | ID: mdl-25196060

ABSTRACT

Proguanil, an anti-malarial prodrug, undergoes cytochrome P450 catalyzed biotransformation to the pharmacologically active triazine metabolite (cycloguanil), which inhibits plasmodial dihydrofolate reductase. This cyclization is catalyzed by CYP2C19 and many anti-malarial lead compounds are being designed and synthesized to exploit this pathway. Quantum chemical calculations were performed using the model species (Cpd I for active species of cytochrome and N4-isopropyl-N6-methylbiguanide for proguanil) to elucidate the mechanism of the cyclization pathway. The overall reaction involves the loss of a water molecule, and is exothermic by approximately 55 kcal/mol, and involves a barrier of approximately 17 kcal/mol. The plausible reaction pathway involves the initial H-radical abstraction from the isopropyl group by Cpd I, followed by two alternative paths- (i) oxygen rebound to provide hydroxyl derivative and (ii) loss of additional H-radical to yield 1,3,5-triazatriene, which undergoes cyclization. This study helped in understanding the role of the active species of cytochromes in this important cyclization reaction.


Subject(s)
Cytochromes/chemistry , Models, Chemical , Proguanil/chemistry , Quantum Theory , Triazines/chemistry , Cyclization
19.
Bioorg Med Chem Lett ; 24(2): 613-7, 2014 Jan 15.
Article in English | MEDLINE | ID: mdl-24361001

ABSTRACT

A new class of compounds based on S-benzylated guanylthiourea has been designed as potential PfDHFR inhibitors using computer aided methods (molecular electrostatic potential, molecular docking). Several compounds in this class have been synthesized starting from guanylthiourea and alkyl bromides. In vitro studies showed that two compounds from this class are active with the IC50 value of 100 µM and 400 nM.


Subject(s)
Drug Design , Folic Acid Antagonists/chemical synthesis , Guanylthiourea/chemical synthesis , Plasmodium falciparum/drug effects , Plasmodium falciparum/enzymology , Crystallography, X-Ray , Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/pharmacology , Folic Acid Antagonists/pharmacology , Guanylthiourea/pharmacology , Protein Structure, Secondary , Protein Structure, Tertiary , Tetrahydrofolate Dehydrogenase/metabolism
20.
Curr Pharm Des ; 19(26): 4755-75, 2013.
Article in English | MEDLINE | ID: mdl-23260024

ABSTRACT

Glycogen Synthase Kinase-3 (GSK-3) is a constitutively acting multifunctional serine/threonine kinase, a role of which has been marked in several physiological pathways, making it a potential target for the treatment of many diseases, including Type-II diabetes and Alzheimer's. Design of GSK-3ß selective inhibitor was the key challenge which led to the use of rational approaches like structure based methods (molecular docking), and ligand based methods (QSAR, pharmacophore mapping) studies. These methods provide insights into the enzyme-ligand interactions and structure activity relationship of different sets of compounds for the design of promising GSK-3 inhibitors. Molecular dynamic simulation studies have additionally been performed to address key issues like the unique requirement of prime phosphorylation of its substrate at P+4 by GSK-3ß. An allosteric site has also been reported, where the binding of the peptide leads to the stabilization of the activation loop, resulting in the enhancement of the catalysis of enzymes. These studies are becoming useful in the design of therapeutically active discriminatory GSK-3 inhibitors. In this article, we present a review of recent efforts and future opportunities for the design of selective GSK-3ß inhibitors.


Subject(s)
Drug Design , Enzyme Inhibitors/chemistry , Glycogen Synthase Kinase 3/antagonists & inhibitors , Enzyme Inhibitors/metabolism , Enzyme Inhibitors/pharmacology , Glycogen Synthase Kinase 3/chemistry , Glycogen Synthase Kinase 3/metabolism , Models, Molecular , Substrate Specificity
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