Study of the interaction of Huperzia saururus Lycopodium alkaloids with the Acetylcholinesterase enzyme

In the present study, we describe and compare the binding modes of three Lycopodium alkaloids (sauroine, 6-hydroxylycopodine and sauroxine; isolated from Huperzia saururus) and huperzine A with the enzyme acetylcholinesterase. Refinement and rescoring of the docking poses (obtained with different programs) with an all atom force field helped to improve the quality of the protein?ligand complexes. Molecular dynamics simulations were performed to investigate the complexes and the alkaloid´s binding modes. The combination of the latter two methodologies indicated that binding in the active site is favored for the active compounds. On the other hand, similar binding energies in both the active and the peripheral sites were obtained for sauroine, thus explaining its experimentally determined lack of activity. MM-GBSA predicted the order of binding energies in agreement with the experimental IC50 valuesFil: Puiatti, Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones En Fisico- Química de Córdoba. Universidad Nacional de Córdoba. Facultad de Cs.químicas. Instituto de Investigaciones En Fisico- Química de Córdoba; ArgentinaFil: Borioni, José Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones En Fisico- Química de Córdoba. Universidad Nacional de Córdoba. Facultad de Cs.químicas. Instituto de Investigaciones En Fisico- Química de Córdoba; ArgentinaFil: Vallejo, Mariana Guadalupe. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Cabrera, Jose Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Agnese, Mariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Ortega, María Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Pierini, Adriana Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones En Fisico- Química de Córdoba. Universidad Nacional de Córdoba. Facultad de Cs.químicas. Instituto de Investigaciones En Fisico- Química de Córdoba; Argentin

Synthesis, Cholinesterase Inhibitory Activity And Molecular Docking Study Of Piperidone-Grafted Pyrimidine And Thiazolopyrimidine Derivatives

Alzheimer’s disease (AD) is the most common form of dementia among the elderly people. Based on the cholinergic hypothesis, loss of cholinergic neurons in AD patients’ brain leads to the decline of acetylcholine (ACh) neurotransmitter level and eventually causes severe dysfunctions in the cholinergic neurotransmission. Thus, increasing the ACh levels is a promising therapeutic approach to restore the substantial impairment of memory and cognitive dysfunctions in AD patients. The search for new cholinesterase inhibitors is still ongoing worldwide. Inspired by the biological significance of pyrimidine-grafted derivatives, especially in cholinesterase inhibition, seventy-four novel pyrimidine embedded derivatives, namely pyridopyrimidines 6(a-l), pyridopyrimidothiones 7(a-l), N-ethyl-pyridopyrimidothiones 8(a-j), N-ethylmorpholino pyridopyrimidothiones 9(a-j), pyrimidinethiols 11(a-l) and thiazolopyrimidines 13(a-r) were synthesized and evaluated for their cholinesterases inhibitory potential against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE)

Production of Bacoside A- A Potent Herbal Drug for Alzheimer in Callus Cultures of Bacopa Monnieri(L.) Pennell

Alzheimer’s disease (AD) is a chronic and progressive neurodegenerative disease .An important approach for treating AD is the inhibition of acetylcholine esterase (AChE) and Monoacylglyceride Lipase (MAGL). Many of the medicinal plants have suggested for treatment of Alzheimer. But only few plants only proved for their Anti-Alzheimeric potential. One such herb is Bacopa monnieri. . Bacosides are most active constituents of Bacopa monnieri. Bacoside A , mostly reported herbal drug- a mixture of four triglycosidic saponins, namely bacoside A3, bacopaside II, bacopasaponin C and the jujubogenin isomer. Its inhibiting potential were analysed by molecular docking. It is having very low binding energy of -20.1 kcal/mol and -12.7 kcal/mol on the targets AChE and MAGL respectively. The druglikeness and toxicity were predicted with ADMET predictor tools namely molinspiration and protox respectively. Bacoside comes under class IV toxicity. This project related to the production of Bacoside A in Callus Cultures of Bacopa monnieri and its enhancements through Elicitation. Elicitor may be defined as a substance which, when introduced in small concentrations to a living cell system, initiates or improves the biosynthesis of specific compounds. Callus of Bacopa monnieri was efficiently induced by 0.5mg/l of NAA. supplement of Auxins IAA was not much efficient in callus induction. Cytokinin BAP was used to inhibit the root formation. The developed fried callus was used for suspension culture under optimised parameters. The suspension cultures were treated under the influence of the Elicitors. HPLC was used for estimation of Bacoside A

Targeting Acetylcholinesterase: Identification of Chemical Leads by High Throughput Screening, Structure Determination and Molecular Modeling

Acetylcholinesterase (AChE) is an essential enzyme that terminates cholinergic transmission by rapid hydrolysis of the neurotransmitter acetylcholine. Compounds inhibiting this enzyme can be used (inter alia) to treat cholinergic deficiencies (e.g. in Alzheimer's disease), but may also act as dangerous toxins (e.g. nerve agents such as sarin). Treatment of nerve agent poisoning involves use of antidotes, small molecules capable of reactivating AChE. We have screened a collection of organic molecules to assess their ability to inhibit the enzymatic activity of AChE, aiming to find lead compounds for further optimization leading to drugs with increased efficacy and/or decreased side effects. 124 inhibitors were discovered, with considerable chemical diversity regarding size, polarity, flexibility and charge distribution. An extensive structure determination campaign resulted in a set of crystal structures of protein-ligand complexes. Overall, the ligands have substantial interactions with the peripheral anionic site of AChE, and the majority form additional interactions with the catalytic site (CAS). Reproduction of the bioactive conformation of six of the ligands using molecular docking simulations required modification of the default parameter settings of the docking software. The results show that docking-assisted structure-based design of AChE inhibitors is challenging and requires crystallographic support to obtain reliable results, at least with currently available software. The complex formed between C5685 and Mus musculus AChE (C5685•mAChE) is a representative structure for the general binding mode of the determined structures. The CAS binding part of C5685 could not be structurally determined due to a disordered electron density map and the developed docking protocol was used to predict the binding modes of this part of the molecule. We believe that chemical modifications of our discovered inhibitors, biochemical and biophysical characterization, crystallography and computational chemistry provide a route to novel AChE inhibitors and reactivators

In Silico Design of Dual-Binding Site Anti-Cholinesterase Phytochemical Heterodimers as Treatment Options for Alzheimer’s Disease

The number of patients with neurodegenerative diseases, particularly Alzheimer’s disease (AD), continues to grow yearly. Cholinesterase inhibitors (ChEIs) represent the first-line symptomatic drug treatment for mild-to-moderate AD; however, there is an unmet need to produce ChEIs with improved efficacy and reduced side effects. Herein, phytochemicals with reported anti-acetylcholinesterase (AChE) activity were ranked in silico for their anti-AChE potential. Ligands with a similar or higher binding affinity to AChE than galantamine were then selected for the design of novel dual-binding site heterodimeric drugs. In silico molecular docking of heterodimers with the target enzymes, AChE and butyrylcholinesterase (BuChE), were performed, and anti-cholinesterase binding affinities were compared with donepezil. Drug-likeliness properties and toxicity of the heterodimers were assessed using the SwissADME and ProTox-II webservers. Nine phytochemicals displayed similar or higher binding affinities to AChE than galantamine: sanguinarine > huperzine A > chelerythrine > yohimbine > berberine > berberastine > naringenin > akuammicine > carvone. Eleven heterodimeric ligands were designed with phytochemicals separated by four- or five-carbon alkyl-linkers. All heterodimers were theoretically potent AChE and BuChE dual-binding site inhibitors, with the highest affinity achieved with huperzine-4C-naringenin, which displayed 34% and 26% improved affinity to AChE and BuChE, respectively, then the potent ChEI drug, donepezil. Computational pharmacokinetic and pharmacodynamic screening suggested that phytochemical heterodimers would display useful gastrointestinal absorption and with relatively low predicted toxicity. Collectively, the present study suggests that phytochemicals could be garnered for the provision of novel ChEIs with enhanced drug efficacy and low toxicity

Discovery of thiazolo [5,4-c] isoquinoline based compounds as acetylcholinesterase inhibitors through computational target prediction, molecular docking and bioassay

We thank Nathalie Reichmann and Leendert Hamoen (University of Amsterdam) for critical reading of the manuscript, Ana Velic (Proteome Center Tübingen) for help with proteome analysis and Mike VanNieuwenhze (Indiana University) for the generous gift of HADA. This study was funded by the European Research Council through grant ERC‐2017‐CoG‐771709 (to MGP), by national funds through FCT– Fundação para a Ciência e a Tecnologia, PTDC/BIA‐MIC/6982/2020 (to HV); PTDC/BIA‐PLA/3432/2012 (to SRF); FCT through MOSTMICRO‐ITQB R&D Unit (UIDB/04612/2020, UIDP/04612/2020) and LS4FUTURE Associated Laboratory (LA/P/0087/2020) and FCT fellowship SFRH/BD/147052/2019 (to BMS); by the Swiss National National Foundation through P300P3_155346 (to AJ); by the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska‐Curie grant agreement No 839596 (to SS) and by the European Molecular Biology Organization through award ALTF 673‐2018 (to SS). Figure 6D and Appendix Fig S7 were created with Biorender.com .A computer-aided drug design (CADD) approach was developed for a focused chemical library comprising a series of sixteen thiazolo[5,4-c]isoquinoline derivatives. Little is known about this group of heteroaromatic compounds, both from the point of view of their synthesis and their biological properties. First, our CADD approach included target prediction by Mondrian conformal prediction with the ChEMBL database. The acetylcholinesterase (AChE) was identified as having a high probability of thiazolo[5,4-c]isoquinolines being active against it. Secondly, the molecular docking predictions revealed four promising thiazoloisoquinolines (2, 7, 13 and 14) according to their prominent ligand-protein energy scores and relevant binding affinities with the AChE pocket residues. The subsequent in vitro evaluation of promising hits and related ones revealed a set of novel AChE inhibitors. Therefore, the findings reported herein may provide a new strategy for discovering novel AChE inhibitors.publishersversionpublishe

Drug discovery and computational strategies in the multitarget drugs era

The pharmaceutical industry is increasingly joining chemoinformatics in the search for the development of new drugs to be used in the treatment of diseases. These computational studies have the advantage of being less expensive and optimize the study time, and thus the interest in this area is increasing. Among the techniques used is the development of multitarget directed ligands (MTDLs), which has become an ascending technique, mainly due to the improvement in the quality of treatment involving several drugs. Multitarget therapy is more effective than traditional drug therapy that emphasizes maximum selectivity for a single target. In this review a multitarget drug survey was carried out as a promising strategy in several important diseases: neglected diseases, neurodegenerative diseases, AIDS, and cancer. In addition, we discuss Computer-Aided Drug Design (CADD) techniques as a tool in the projection of multitarget compounds against these diseases

Binding free energy calculations to rationalize the interactions of huprines with acetylcholinesterase

In the present study, the binding free energy of a family of huprines with acetylcholinesterase (AChE) is calculated by means of the free energy perturbation method, based on hybrid quantum mechanics and molecular mechanics potentials. Binding free energy calculations and the analysis of the geometrical parameters highlight the importance of the stereochemistry of huprines in AChE inhibition. Binding isotope effects are calculated to unravel the interactions between ligands and the gorge of AChE. New chemical insights are provided to explain and rationalize the experimental results. A good correlation with the experimental data is found for a family of inhibitors with moderate differences in the enzyme affinity. The analysis of the geometrical parameters and interaction energy per residue reveals that Asp72, Glu199, and His440 contribute significantly to the network of interactions between active site residues, which stabilize the inhibitors in the gorge. It seems that a cooperative effect of the residues of the gorge determines the affinity of the enzyme for these inhibitors, where Asp72, Glu199, and His440 make a prominent contribution

Identification of potential AChE inhibitors through combined machine-learning and structure-based design approaches

Alzheimer’s disease (AD) is an irreversible, progressive neurodegenerative disease characterised by dementia.The depletion of acetylcholine (ACh) is involved the synaptic cleft is responsible for dementia due to neuronal loss. The acetylcholinesterase (AChE) enzyme isinvolved in the hydrolytic degradation of ACh and its inhibition is therapeutically beneficial for the treatment in memory loss.The use of machine learning (ML) for the identification of enzyme inhibitors has recently become popular. It identifies important patterns in the reported inhibitors to predict the new molecules. Hence, in this study, a set of support vector classifier-based ML models were developed,validated and employed to predict AChE inhibitors. Further, 247 predicted compounds obtained through PAINS and molecular property filters were docked on the AChE enzyme. The docking study identified compounds AAM132011183, ART21232619 and LMG16204648 as AChE inhibitors with suitable ADME properties. The selected compounds produced stable interactions with enzymes in molecular dynamics studies. The novel inhibitors obtained from the study may be proposed as active leads for AChE inhibition