Tacrine-coumarin and Tacrine-7-chloroquinoline Hybrids with Thiourea Linkers: Cholinesterase Inhibition Properties, Kinetic Study, Molecular Docking and Permeability Assay for Blood-brain Barrier

2018 ◽  
Vol 15 (12) ◽  
pp. 1096-1105 ◽  
Author(s):  
Slavka Hamulakova ◽  
Ladislav Janovec ◽  
Ondrej Soukup ◽  
Daniel Jun ◽  
Jana Janockova ◽  
...  
Keyword(s):  
Blood Brain Barrier ◽  
Mixed Type ◽  
Acetylcholinesterase Inhibitors ◽  
Docking Studies ◽  
Brain Barrier ◽  
Ache Inhibitor ◽  
Cholinesterase Inhibition ◽  
Binding Modes ◽  
Blood Brain ◽  
Ic50 Values

Background: The design of new heterodimeric dual binding site acetylcholinesterase inhibitors constitutes the main goal-directed to the development of new anticholinesterase agents with the expanded pharmacological profile. Multi-target compounds are usually designed by combining in a hybrid molecule with two or more pharmacophoric moieties that are known to enable interaction with the selected molecular targets. Methods: All compounds were tested for their inhibitory activity on human AChE/BChE. The Ellman´s method was used to determine inhibition kinetics and IC50 values. In order to predict passive bloodbrain penetration of novel compounds, modification of the parallel artificial membrane permeation assay has been used. Docking studies were performed in order to predict the binding modes of new hybrids with hAChE/ hBChE respectively. Results: In this study, we described the design, synthesis, and evaluation of series tacrine-coumarin and tacrine-quinoline compounds which were found to show potential inhibition of ChEs and penetration of the blood-brain barrier. Conclusion: Tacrine-quinoline hybrids 7a exhibited the highest activity towards hBChE (IC50 = 0.97 µmol) and 7d towards hAChE (IC50 = 0.32 µmol). Kinetic and molecular modelling studies revealed that 7d was a mixed-type AChE inhibitor (Ki = 1.69 µmol) and 7a was a mixed-type BChE inhibitor (Ki = 1.09 µmol). Moreover, hybrid 5d and 7c could penetrate the CNS.

MEIC Evaluation of Acute Systemic Toxicity

1998 ◽  
Vol 26 (2_suppl) ◽  
pp. 617-658 ◽  
Author(s):  
Björn Ekwall ◽  
Frank A. Barile ◽  
Argelia Castano ◽  
Cecilia Clemedson ◽  
Richard H. Clothier ◽  
...  
Keyword(s):  
Cell Line ◽  
Blood Brain Barrier ◽  
Human Cell ◽  
Human Cell Line ◽  
Brain Barrier ◽  
Human Toxicity ◽  
Blood Concentrations ◽  
Blood Brain ◽  
Ic50 Values

The Multicenter Evaluation of In Vitro Cytotoxicity (MEIC) programme was set up to evaluate the relevance for human acute toxicity of in vitro cytotoxicity tests. At the end of the project in 1996, 29 laboratories had tested all 50 reference chemicals in 61 cytotoxicity assays. Five previous articles have presented the in vitro data and the human database to be used in the evaluation. This article presents three important parts of the final evaluation: a) a comparison of rat and mouse oral LD50 with human acute lethal doses for all 50 chemicals; b) a display of the correlations between IC50 (concentration causing 50% inhibition) values from all 61 assays and three independent sets of human acute lethal blood concentrations, i.e. clinical lethal concentrations, forensic lethal concentrations, and peak concentrations; and c) a series of comparisons between average IC50 values from ten human cell line 24-hour assays and human lethal blood concentrations. In the latter comparisons, results from correlations were linked with known human toxicity data for the chemicals, to provide an understanding of correlative results. This correlative/mechanistic approach had the double purpose of assessing the relevance of the in vitro cytotoxicities, and of testing a series of hypotheses connected with the basal cytotoxicity concept. The results of the studies were as follows. Rat LD50 predictions of human lethal dosage were only relatively good (R2 = 0.61), while mouse LD50s gave a somewhat better prediction (R2 = 0.65). Comparisons performed between IC50 values from the 61 assays and the human lethal peak concentrations demonstrated that human ceil line tests gave the best average results (R2 = 0.64), while mammalian and fish cell tests correlated less well (R2 = 0.52–0.58), followed by non-fish ecotoxicological tests (R2 = 0.36). Most of the 61 assays underpredicted human toxicity for digoxin, malathion, carbon tetrachloride and atropine sulphate. In the correlative/mechanistic study, the 50 chemicals were first separated into three groups: A = fast-acting chemicals with a restricted passage across the blood–brain barrier; B = slow-acting chemicals with a restricted passage across the blood–brain barrier; and C = chemicals which cross the blood–brain barrier freely, while inducing a non-specific excitation/depression of the central nervous system (CNS). The IC50 values for chemicals in group C were divided by a factor of ten to compensate for a hypothetical extra vulnerability of the CNS to cytotoxicity. Finally, the average human cell line IC50 values (24-hour IC50 for groups A and C, and after 48-hour for group B) were compared with relevant human lethal blood concentrations (peak concentrations for groups A and C, and 48-hour concentrations for group B). As a result, in vitro toxicity and in vivo toxicity correlated very well for all groups (R2 = 0.98, 0.82 and 0.85, respectively). No clear overprediction of human toxicity was made by the human cell tests. The human cell line tests underpredicted human toxicity for only four of the 50 chemicals. These outlier chemicals were digoxin, malathion, nicotine and atropine sulphate, all of which have a lethal action in man through interaction with specific target sites not usually found in cell lines. Potassium cyanide has a cellular human lethal action which cannot be measured by standard anaerobic cell lines. The good prediction of the human lethal whole-blood concentration of this chemical was not conclusive, i.e. was probably a “false good correlation”. Another two chemicals in group C resulted in “false good correlations”, i.e. paracetamol and paraquat. The comparisons thus indicated that human cell line cytotoxicities are relevant for the human acute lethal action for 43 of the 50 chemicals. The results strongly support the basal cytotoxicity concept, and further point to the non-specific CNS depression being the obligatory reaction of humans to cytotoxic concentrations of chemicals, provided that the chemicals are able to pass the blood–brain barrier.

scholarly journals Juniperus Communis Extract Exerts Antitumor Effects in Human Glioblastomas Through Blood-Brain Barrier

2018 ◽  
Vol 49 (6) ◽  
pp. 2443-2462 ◽  
Author(s):  
◽  
Nu-Man Tsai ◽  
Kai-Fu Chang ◽  
Jun-Cheng Wang
Keyword(s):  
Blood Brain Barrier ◽  
Cell Lines ◽  
Glioma Cell ◽  
Glioma Cells ◽  
Brain Barrier ◽  
Flow Cytometry Analysis ◽  
Juniperus Communis ◽  
Blood Brain ◽  
Ic50 Values

Background/Aims: Herbal materials derived from Juniperus communis (JCo) possess anticancer activity. In this study, we evaluated the efficacy of a JCo berry extract in suppressing glioblastoma growth. Methods: The effects of JCo extract on the viability of normal and glioma cell lines was analyzed using a modified 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The synergistic therapeutic effect of JCo extract and temozolomide (TMZ) on glioma cells was examined by MTT analysis. Flow cytometry analysis, the terminal deoxynucleotidyl transferase-mediated nick end labeling (TUNEL) test, and western blotting were performed to identify the apoptotic pathway. To determine the in vivo efficacy of the JCo extract, rats were injected with 5 × 104 rat glioma RG2 cells in the back skin and brain hemisphere and then received a subcutaneous injection in the back skin that contained either JCo extract or vehicle. Finally, blood and histologic examinations were performed to evaluate JCo toxicity. Results: The IC50 values of JCo extract were 57–69 µg/mL and 49–67 µg/mL in the glioblastoma cell lines after 24 and 48 h, respectively. However, in non-tumor cell lines, the respective IC50 values of JCo extract were 76–105 µg/mL and 77–108 µg/mL. The JCo extract had a stronger cytotoxicity and a larger range of IC50 values in glioma than in normal cells as compared to those effects caused by temozolomide (TMZ). In addition, the results of flow cytometry analysis, TUNEL test, and western blotting revealed that the JCo extract induced glioma cell cycle arrest through intrinsic and extrinsic apoptotic pathways. In the in vivo studies, a significant reduction of tumor size in JCo-treated rats, as measured by animal MRI, demonstrated that the JCo extract effectively inhibited glioma cell growth and successfully penetrated the blood-brain barrier. The immunohistochemical (IHC) staining detected positive signals of PCNA, VEGFR-1, and VEGFR -2 in 44.49%, 5.88%, and 5.85% of JCo-treated glioma cells, respectively. However, positive signals of PCNA, VEGFR-1, and VEGFR-2 were detected in 73.08%, 9.67%, and 11.70% of vehicle-treated glioma cells, respectively. The IHC examination of PCNA and VEGFR-1 and -2 indicated that JCo extract significantly decreased the degree of neovascularization. However, no significant differences in serum levels of blood cell count and hepatic enzymes, renal function index, and the histologic appearance of vital organs were detected between the JCo and vehicle-treated rats. Conclusion: The JCo extract penetrated the blood-brain barrier and significantly induced glioma cell apoptosis by reducing neovascularization via suppression of the PI3K/AKT/mTOR pathway. Furthermore, JCo extract was less cytotoxic to non-neoplastic vital organs than TMZ.

scholarly journals In Vitro and In Silico Acetylcholinesterase Inhibitory Activity of Thalictricavine and Canadine and Their Predicted Penetration across the Blood-Brain Barrier

Molecules ◽  
2019 ◽  
Vol 24 (7) ◽  
pp. 1340 ◽  
Author(s):  
Jakub Chlebek ◽  
Jan Korábečný ◽  
Rafael Doležal ◽  
Šárka Štěpánková ◽  
Daniel Pérez ◽  
...  
Keyword(s):  
Blood Brain Barrier ◽  
In Silico ◽  
Binding Mode ◽  
Brain Barrier ◽  
In Silico Docking ◽  
Lead Compounds ◽  
Blood Brain ◽  
Type Pattern ◽  
Ic50 Values

In recent studies, several alkaloids acting as cholinesterase inhibitors were isolated from Corydalis cava (Papaveraceae). Inhibitory activities of (+)-thalictricavine (1) and (+)-canadine (2) on human acetylcholinesterase (hAChE) and butyrylcholinesterase (hBChE) were evaluated with the Ellman’s spectrophotometric method. Molecular modeling was used to inspect the binding mode of compounds into the active site pocket of hAChE. The possible permeability of 1 and 2 through the blood–brain barrier (BBB) was predicted by the parallel artificial permeation assay (PAMPA) and logBB calculation. In vitro, 1 and 2 were found to be selective hAChE inhibitors with IC50 values of 0.38 ± 0.05 µM and 0.70 ± 0.07 µM, respectively, but against hBChE were considered inactive (IC50 values > 100 µM). Furthermore, both alkaloids demonstrated a competitive-type pattern of hAChE inhibition and bind, most probably, in the same AChE sub-site as its substrate. In silico docking experiments allowed us to confirm their binding poses into the active center of hAChE. Based on the PAMPA and logBB calculation, 2 is potentially centrally active, but for 1 BBB crossing is limited. In conclusion, 1 and 2 appear as potential lead compounds for the treatment of Alzheimer’s disease.

scholarly journals Synthesis of New Quinoline-Piperonal Hybrids as Potential Drugs against Alzheimer’s Disease

2019 ◽  
Vol 20 (16) ◽  
pp. 3944 ◽  
Author(s):  
Juliana de Oliveira C. Brum ◽  
Denise Cristian F. Neto ◽  
Joyce Sobreiro F. D. de Almeida ◽  
Josélia Alencar Lima ◽  
Kamil Kuca ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Theoretical Analysis ◽  
Blood Brain Barrier ◽  
Docking Studies ◽  
New Drugs ◽  
Brain Barrier ◽  
Inhibitory Capacity ◽  
Blood Brain ◽  
Inhibitory Activities

Six quinoline-piperonal hybrids were synthesized and evaluated as potential drugs against Alzheimer’s disease (AD). Theoretical analysis of the pharmacokinetic and toxicological properties of the compounds suggest that they present good oral bio-availability and are also capable of penetrating the blood–brain barrier, qualifying as leads for new drugs against AD. Evaluation of their inhibitory capacity against acetyl- and butyrilcholinesterases (AChE and BChE) through Ellmann’s test showed that three compounds present promising results with one of them being capable of inhibiting both enzymes. Further docking studies of the six compounds synthesized helped to elucidate the main interactions that may be responsible for the inhibitory activities observed.

Design and synthesis of novel tacrine–indole hybrids as potential multitarget-directed ligands for the treatment of Alzheimer's disease

2021 ◽  
Author(s):  
Slavka Hamulakova ◽  
Zuzana Kudlickova ◽  
Ladislav Janovec ◽  
Roman Mezencev ◽  
Zachery J Deckner ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Blood Brain Barrier ◽  
Acetylcholinesterase Inhibitors ◽  
Biological Evaluation ◽  
Brain Barrier ◽  
Amyloid Formation ◽  
Design And Synthesis ◽  
Blood Brain ◽  
Β Amyloid

The authors report on the synthesis and biological evaluation of new compounds whose structure combines tacrine and indole moieties. Tacrine–indole heterodimers were designed to inhibit cholinesterases and β-amyloid formation, and to cross the blood–brain barrier. The most potent new acetylcholinesterase inhibitors were compounds 3c and 4d (IC50 = 25 and 39 nM, respectively). Compound 3c displayed considerably higher selectivity for acetylcholinesterase relative to human plasma butyrylcholinesterase in comparison to compound 4d (selectivity index: IC50 [butyrylcholinesterase]/IC50 [acetylcholinesterase] = 3 and 0.6, respectively). Furthermore, compound 3c inhibited β-amyloid-dependent amyloid nucleation in the yeast-based prion nucleation assay and displayed no dsDNA destabilizing interactions with DNA. Compounds 3c and 4d displayed a high probability of crossing the blood–brain barrier. The results support the potential of 3c for future development as a dual-acting therapeutic agent in the prevention and/or treatment of Alzheimer's disease.

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