Fluoxetine and sertraline based multitarget inhibitors of cholinesterases and monoamine oxidase-A/B for the treatment of Alzheimer's disease: Synthesis, pharmacology and molecular modeling studies

Latest advances in dual inhibitors of acetylcholinesterase and monoamine oxidase B against Alzheimer's disease

Alzheimer's disease (AD) is a progressive brain disease characterised by progressive memory loss and cognition impairment, ultimately leading to death. There are three FDA-approved acetylcholinesterase inhibitors (donepezil, rivastigmine, and galantamine, AChEIs) for the symptomatic treatment of AD. Monoamine oxidase B (MAO-B) has been considered to contribute to pathologies of AD. Therefore, we reviewed the dual inhibitors of acetylcholinesterase (AChE) and MAO-B developed in the last five years. In this review, these dual-target inhibitors were classified into six groups according to the basic parent structure, including chalcone, coumarin, chromone, benzo-fused five-membered ring, imine and hydrazine, and other scaffolds. Their design strategies, structure-activity relationships (SARs), and molecular docking studies with AChE and MAO-B were analysed and discussed, giving valuable insights for the subsequent development of AChE and MAO-B dual inhibitors. Challenges in the development of balanced and potent AChE and MAO-B dual inhibitors were noted, and corresponding solutions were provided.

In vitro anti-inflammatory, antidiabetic, antibacterial, and in silico studies of Ferruginan A isolated from Olea ferruginea Royle (Oleaceae)

Objective

Traditionally, Olea ferruginea Royle (Oleaceae) has been used as a painkiller and antidiabetic in various ailments. To provide a scientific background to this folklore the current study was designed to anti-inflammatory and antidiabetic effects of one of the isolated compound from this plant.

Methods

Ferruginan A was isolated from the ethyl acetate extract of Olea ferruginea bark. This isolated molecule was subjected to in-vitro anti-inflammatory and antidiabetic effects using HRBCs and glucose uptake tests. The compound was also tested for molecular docking and ADMET study.

Results

Regarding the anti-inflammatory effect, the tested compound demonstrated a 69.82 % inhibition at a concentration of 100 µg/mL, while the Ferruginan A (100 µl/mL) increased the uptake of glucose (3.79-71.86 %) in the yeast cell. Similarly, the zone of inhibition values of Ferruginan A (24.98 mm) against Escherichia coli were found to be comparable to standard (Imipenem: 31.09 mm). The mechanism of antidiabetic and anti-inflammatory effects was explored by using docking simulations performed on four molecular targets related to diabetes and inflammation. The results showed that the isolated compound may act as an antidiabetic agent by inhibiting the 5' Adenosine monophosphate-activated protein kinase (AMPK). While it also showed inhibition of anti-inflammatory targets COX-1, COX-2, and Tumor necrosis factor alpha (TNF-α). The ADMET prediction study revealed that isolated compound possesses favorable ADMET profile.

Conclusion

It was concluded that Ferruginan A might be a significant anti-inflammatory and antidiabetic molecule.

Evaluation of pyrimidine/pyrrolidine-sertraline based hybrids as multitarget anti-Alzheimer agents: In-vitro, in-vivo, and computational studies

Alzheimer's disease (AD) is a complex, multifactorial and most prevalent progressive neurodegenerative ailment. Its multifactorial and complex nature causes the lack of disease modifying drugs. Hence, multi-target drug design strategies have been adopted to halt the progression of AD. In current research, we applied multitarget strategy to tackle multifactorial nature of AD. Rational design and synthesis of framework of hybrids containing Pyrimidine/pyrrolidine-sertraline scaffolds were carried out. The synthesized compounds were further evaluated for their in-vitro enzyme inhibition potential against cholinesterases, monoamine oxidases and β-site amyloid precursor protein cleaving enzyme-1 (BACE-1). Compound 19 emerged as an optimal multipotent hybrid with IC₅₀ values of 0.07 µM, 0.09 µM, 0.63 µM, 0.21 µM and 0.73 µM against AChE, BChE, MAO-A, MAO-B and BACE-1 respectively. After in-vivo cytotoxicity and in-vitro PAMPA blood brain barrier permeation assays, a number of widely used behavioral assessment tests were also performed for the evaluation of memory and learning.Determination of biochemical parameters showed low levels of acetylcholinesterase by the treatment with synthesized compounds. Furthermore, levels of neurotransmitters such as serotonin, dopamine and noradrenaline were also analyzed. Increased neurotransmitter levels showed the improved short and long-term memory as well as enhanced learning behavior. Docking studies on the target enzymes showed correlation with the experimental in-vitro enzyme inhibition results.

In-Vitro, In-Vivo, Molecular Docking and ADMET Studies of 2-Substituted 3,7-Dihydroxy-4H-chromen-4-one for Oxidative Stress, Inflammation and Alzheimer's Disease

Plants' bioactives are well-known safe drugs for vital diseases. Flavones and Flavonoid-rich dietary supplements are known to exhibit neuroprotective potential. In this study, we isolated a flavone 2-(3,4-dimethoxyphenyl)-3,7-dihydroxy-4H-chromen-4-one from Notholirion thomsonianum and it was evaluated against various targets of the oxidative stress-related neurological disorders. The compound showed excellent acetyl and butyrylcholinesterase inhibitions in its profile, giving IC50 values of 1.37 and 0.95 μM, respectively. Similarly, in in-vitro MAO-B assay, our flavone exhibited an IC50 value of 0.14 μM in comparison to the standard safinamide (IC50 0.025 μM). In in-vitro anti-inflammatory assay, our isolated compound exhibited IC50 values of 7.09, 0.38 and 0.84 μM against COX-1, COX-2 and 5-LOX, respectively. The COX-2 selectivity (SI) of the compound was 18.70. The compound was found safe in animals and was very effective in carrageenan-induced inflammation. Due to the polar groups in the structure, a very excellent antioxidant profile was observed in both in-vitro and in-vivo models. The compound was docked into the target proteins of the respective activities and the binding energies confirmed the potency of our compound. Furthermore, absorption, distribution, metabolism, excretion, and toxicity (ADMET) results showed that the isolated flavone has a good GIT absorption ability and comes with no hepatic and cardiotoxicity. In addition, the skin sensitization test, in-vitro human cell line activation test (h-CLAT) and KeratinoSens have revealed that isolated flavone is not skin sensitive with a confidence score of 59.6% and 91.6%. Herein, we have isolated a natural flavone with an effective profile against Alzheimer's, inflammation and oxidative stress. The exploration of this natural flavone will provide a baseline for future research in the field of drug development.

Design, synthesis, in-vitro, in-vivo and ex-vivo pharmacology of thiazolidine-2,4-dione derivatives as selective and reversible monoamine oxidase-B inhibitors

Neurodegenerative ailments are a diverse set of syndromes distinguished by gradual deterioration of the structure as well as functions of the central nervous system or peripheral nervous system. Alzheimer's disease (AD) and Parkinson's disease (PD) have no cure, common, and are high prevalent neurodegenerative pathologies. In current research, rationally designed thiazolidine-2,4-dione based analogs were synthesized and tested for their inhibition potential against two isoforms of monoamine oxidase (MAO-A / MAO-B). Structure activity relationships were explored. Pyridinyl and thiazolyl hydrazone derivative 43 and 44 with IC₅₀ value of 0.013 µM and 0.008 µM (selectivity 228 / 226 times) exhibited higher potency than reference drug safinamide. Most active compounds showed BBB penetration in PAMPA in-vitro assay. Except nitro derivative 41, all compounds were non-neurotoxic in the studied concentration. Molecular docking studies supported the in-vitro experimental results and the selectivity by comparing the binding energy values against both MAO-A and MAO-B isoforms. All the results of current research suggest compounds 43 and 44 may serve as promising candidates for further research for treatment of neurodegenerative diseases.

Design, synthesis, antiproliferative activity, estrogen receptors binding affinity of C-3 pregnenolone-dihydropyrimidine derivatives for the treatment of breast cancer

Breast cancer (BCa) is very common malignancy and globally, has become the second leading cause of cancer death among women. For the treatment of BCa, estrogen receptors-alpha (ERα) has proven to be a therapeutic target. In continuation of our previous reported dihydropyrimidine-based pregnenolone derivatives, we modified at C-3 hydroxyl group. Structural architecture of estrogen receptors (ER) with excellent ER binding affinity was used for modification. MTT assay was used to evaluate the synthesized steroidal analogs for their antiproliferative activities against ER-positive MCF-7, ER-negative MDA-MB-231 (ER^-) breast cancer cells and non-cancerous HEK-293 cells. Structure activity relationship (SAR) studies revealed that diethanolamine containing pregnenolone derivatives showed significant cytotoxicity against ER + MCF-7 and also showed good binding affinity with ERα and are relatively safe against HEK-293 cell model. Docking studies demonstrated that high binding affinity of diethanolamine analogs is due to their binding interaction with key amino acid residues present in the binding site of Erα.

Design, Synthesis, and Bioevaluation of Indole Core Containing 2-Arylidine Derivatives of Thiazolopyrimidine as Multitarget Inhibitors of Cholinesterases and Monoamine Oxidase A/B for the Treatment of Alzheimer Disease

In continuation of our previous study to identify multitarget inhibitors of cholinesterases (ChEs) and monoamine oxidase (MAOs) isoforms, we synthesized and evaluated 2-arylidine derivatives of thiazolopyrimidine for the treatment of Alzheimer disease. Three series of compounds with different linker size and target-anchoring functional groups were synthesized. Compounds 34-37 showed excellent to good AChE and BChE inhibition potential at nanomolar to low micromolar concentration. While all the compounds showed excellent MAO-B inhibition and selectivity relative to MAO-A, compounds 25 and 36 emerged as the most potent MAO-B inhibitors of all the series of synthesized compounds with IC₅₀ values of 0.13 μM and 0.10 μM, respectively. Furthermore, kinetic studies of inhibitor 35 showed mixed inhibition mode. Exploration of structure activity relationship (SAR) revealed the role of functionalities and length of linkers on potency. Acute toxicity evaluation showed the safety of tested compounds up to 2000 mg/kg dose. PAMPA-BBB evaluation showed BBB permeability of the tested compounds, while MTT assay performed on neuroblastoma SHSY5Y cells showed that all the tested compounds are non-neurotoxic in the tested concentrations. Docking studies showed a strong correlation with experimental in vitro results via binding orientations and interaction patterns of the synthesized compounds into the binding sites of target enzymes. We have successfully identified safe, non-neurotoxic, and blood brain barrier permeable multitarget lead compounds for the treatment of AD.

Diclofenac derivatives as concomitant inhibitors of cholinesterase, monoamine oxidase, cyclooxygenase-2 and 5-lipoxygenase for the treatment of Alzheimer's disease: synthesis, pharmacology, toxicity and docking studies

Targeting concomitantly cholinesterase (ChEs) and monoamine oxidases (MAO-A and MAO-B) is one of the key strategies to treat multifactorial Alzheimer's disease (AD).