Lead optimization based design, synthesis, and pharmacological evaluation of quinazoline derivatives as multi-targeting agents for Alzheimer's disease treatment

The complexity and multifaceted nature of Alzheimer's disease (AD) have driven us to further explore quinazoline scaffolds as multi-targeting agents for AD treatment. The lead optimization strategy was utilized in designing of new series of derivatives (AK-1 to AK-14) followed by synthesis, characterization, and pharmacological evaluation against human cholinesterase's (hChE) and β-secretase (hBACE-1) enzymes. Amongst them, compounds AK-1, AK-2, and AK-3 showed good and significant inhibitory activity against both hAChE and hBACE-1 enzymes with favorable permeation across the blood-brain barrier. The most active compound AK-2 revealed significant propidium iodide (PI) displacement from the AChE-PAS region and was non-neurotoxic against SH-SY5Y cell lines. The lead molecule (AK-2) also showed Aβ aggregation inhibition in a self- and AChE-induced Aβ aggregation, Thioflavin-T assay. Further, compound AK-2 significantly ameliorated Aβ-induced cognitive deficits in the Aβ-induced Morris water maze rat model and demonstrated a significant rescue in eye phenotype in the Aꞵ-phenotypic drosophila model of AD. Ex-vivo immunohistochemistry (IHC) analysis on hippocampal rat brains showed reduced Aβ and BACE-1 protein levels. Compound AK-2 suggested good oral absorption via pharmacokinetic studies and displayed a good and stable ligand-protein interaction in in-silico molecular modeling analysis. Thus, the compound AK-2 can be regarded as a lead molecule and should be investigated further for the treatment of AD.

DFT/TDDFT calculations of geometry optimization, electronic structure and spectral properties of clevudine and telbivudine for treatment of chronic hepatitis B

Chronic hepatitis B remains a worldwide health concern. Presently, many drugs, such as Clevudine and Telbivudine, are recommended for the treatment of chronic hepatitis B disease. For this purpose, the quantum chemical analysis of ELUMO-HOMO (Egap), ionization potential (IP), electron affinity (EA), electronegativity (EN), chemical hardness (η), chemical potential (μ), chemical softness (S), electrophilicity index (ω), electron accepting capability (ω+), electron-donating capability (ω-), Nucleophilicity index (N), additional electronic charge (∆Nmax), Optical softness (σ0) and Dipole Moment, IR and UV-Vis spectra, molecular electrostatic potential (MEP) profile, Mulliken charge analysis, natural bond orbital (NBO) were examined in this study. The dipole moment of the compounds suggests their binding pose and predicted binding affinity. The electrophilic and nucleophilic regions were identified, and techniques such as NBO, UV-Vis, and IR were used to gain insights into the molecular structure, electronic transitions, and potential drug design for Hepatitis B treatment. Calculations for this study were carried out using the Gaussian 09 program package coupled with the DFT/TDDFT technique. The hybrid B3LYP functional method and the 6-311++G(d, p) basis set were used for the calculations.

Multi-Target Effect of Aloeresin-A against Bacterial and Host Inflammatory Targets Benefits Contact Lens-Related Keratitis: A Multi-Omics and Quantum Chemical Investigation

Contact lens-mediated microbial keratitis caused by Pseudomonas aeruginosa and Streptococcus pneumoniae provokes corneal damage and vision loss. Recently, natural phytochemicals have become complementary medicines for corneal destruction. Herein, we aimed to identify multi-targeting Aloe vera-derived phytochemicals capable of inhibiting bacterial and host targets of keratitis through ADME (absorption, distribution, metabolism, and excretion), docking, molecular dynamics (MD) simulation, MMGBSA (molecular mechanics generalized Born surface area) and density functional theory (DFT) investigations. An extensive literature search revealed ExoU, ExoS, ExoT, ExoY, and PLY as virulent bacterial targets. Simultaneously, differential gene expression (DGE) and pathway enrichment analysis-specified host transcription factor (SPI1) influences keratitis pathogenesis. Molecular docking analysis uncovered aloeresin-A as a promising inhibitor against bacterial and host targets, demonstrating strong binding energies ranging from -7.59 to -6.20 kcal/mol. Further, MMGBSA and MD simulation analysis reflect higher binding free energies and stable interactions of aloeresin-A with the targets. In addition, DFT studies reveal the chemical reactiveness of aloeresin-A through quantum chemical calculations. Hence, our findings show aloeresin-A to be a promising candidate for effectively inhibiting keratitis. However, additional research is imperative for potential integration into lens care solutions.

Design, Synthesis, and Biological Evaluation of Piperazine and N-Benzylpiperidine Hybrids of 5-Phenyl-1,3,4-oxadiazol-2-thiol as Potential Multitargeted Ligands for Alzheimer's Disease Therapy

Our present work demonstrates the successful design and synthesis of a new class of compounds based upon a multitargeted directed ligand design approach to discover new agents for use in Alzheimer's disease (AD). All the compounds were tested for their in vitro inhibitory potential against human acetylcholinesterase (hAChE), human butylcholinesterase (hBChE), β-secretase-1 (hBACE-1), and amyloid β (Aβ) aggregation. Compounds 5d and 5f have shown hAChE and hBACE-1 inhibition comparable to donepezil, while hBChE inhibition was comparable to rivastigmine. Compounds 5d and 5f also demonstrated a significant reduction in the formation of Aβ aggregates through the thioflavin T assay and confocal, atomic force, and scanning electron microscopy studies and significantly displaced the total propidium iodide, that is, 54 and 51% at 50 μM concentrations, respectively. Compounds 5d and 5f were devoid of neurotoxic liabilities against RA/BDNF (RA = retinoic acid; BDNF = brain-derived neurotrophic factor)-differentiated SH-SY5Y neuroblastoma cell lines at 10-80 μM concentrations. In both the scopolamine- and Aβ-induced mouse models for AD, compounds 5d and 5f demonstrated significant restoration of learning and memory behaviors. A series of ex vivo studies of hippocampal and cortex brain homogenates showed that 5d and 5f elicit decreases in AChE, malondialdehyde, and nitric oxide levels, an increase in glutathione level, and reduced levels of pro-inflammatory cytokines, tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6) mRNA. The histopathological examination of mice revealed normal neuronal appearance in the hippocampal and cortex regions of the brain. Western blot analysis of the same tissue indicated a reduction in Aβ, amyloid precursor protein (APP)/Aβ, BACE-1, and tau protein levels, which were non-significant compared to the sham group. The immunohistochemical analysis also showed significantly lower expression of BACE-1 and Aβ levels, which was comparable to donepezil-treated group. Compounds 5d and 5f represent new lead candidates for developing AD therapeutics.

Crystal structure and optical characterization of a new hybrid compound, C6H9N2FeCl4, with large dielectric constants for field-effect transistors

Due to remarkable dielectric features, such as a large dielectric constant, strong electrical conductivity, high capacitance, and low dielectric loss, hybrid materials have lately seen a huge number of applications in the field of optoelectronics. These are critical characteristics that qualify the performance of optoelectronic devices, particularly field-effect transistor components (FETs). Here, the hybrid compound 2-amino-5-picoline tetrachloroferrate(iii) (2A5PFeCl₄) was synthesised by using the slow evaporation solution growth method at room temperature. Structural, optical, and dielectric properties have been investigated. The 2A5PFeCl₄ compound crystallises in the monoclinic system (P2₁/c space group). Its structure can be described as a successive layering of inorganic and organic parts. [FeCl₄]^- tetrahedral anions and 2-amino-5-picolinium cations are connected by N-H⋯Cl and C-H⋯Cl hydrogen bonds. The optical absorption measurement confirms the semiconductor nature with a band gap of around 2.47 eV. Additionally, the structural and electronic properties of the title compound have been investigated theoretically through DFT calculations. At low frequencies, this material has significant dielectric constants (ε ∼10⁶). Furthermore, the high electrical conductivity, low dielectric loss at high frequencies, and high capacitance show that this new material has great dielectric potential in FET technologies. Due to their high permittivity, these compounds can be employed as gate dielectrics.

DFT analysis and in silico exploration of drug-likeness, toxicity prediction, bioactivity score, and chemical reactivity properties of the urolithins

Urolithins (Uro) are human microflora-derived metabolites of ellagic acid and ellagitannins. It has been shown to be a powerful modulator of oxidative stress, agents with potential anti-inflammatory, antiproliferative, and antiaging properties. The present study aimed to explore the drug-likeness, toxicity, and bioactivity score of urolithins that were required to be considered oral drug-active using the web-based softwares, Molinspiration, and protox_II. In addition, the chemical reactivity descriptors of the urolithins (Uro A, Uro B, Uro, C, Uro D) were also determined through density functional (DFT) calculations. Furthermore, electrostatic potential (MEP), natural bonds orbitals (NBO), HOMO-LUMO energies, chemical reactivity descriptors, dipole moment, and Fukui functions of all the urolithins were investigated by resorting the conceptual of DFT at the M06-2X/6-311++G (d, p) basis set as a tool to analyse and comprehend the molecular interaction. The results showed that all the urolithins comply with the Lipinski's rule of five and have biological activity. According to the toxicity predictions, Uro A, Uro C, and Uro D belong to class 4 while Uro B belongs to class 6. The chemical reactivity and stability features of the investigated compounds were evaluated using global chemical reactivity descriptors calculated from the Frontier Molecular Orbitals (FMOs) energies gap, which revealed that the stability order of the molecules was Uro B > Uro C > Uro D > Uro A. The present findings indicate that the urolithins could be a promising candidate for development into a therapeutic medication.Communicated by Ramaswamy H. Sarma.

Chemosensing Properties of Coumarin Derivatives: Promising Agents with Diverse Pharmacological Properties, Docking and DFT Investigation

In this work, a three-component reaction of 3-acetyl-4-hydroxycoumarine, malononitrile, or cyanoacetate in the presence of ammonium acetate was used to form coumarin derivatives. The chemical structures of new compounds were identified by ¹H, ¹³C NMR and an elemental analysis. These compounds were examined in vitro for their antimicrobial activity against a panel of bacterial strains. In addition, these compounds were investigated for antioxidant activities by superoxideradical, DPPH (2,2-Diphenyl-1-picrylhydrazyl), and hydroxyl radical scavenging assays, in which most of them displayed significant antioxidant activities. Furthermore, these compounds were evaluated for anti-inflammatory activity by indirect hemolytic and lipoxygenase inhibition assays and revealed good activity. In addition, screening of the selected compounds 2–4 against colon carcinoma cell lines (HCT-116) and hepatocellular carcinoma cell lines (HepG-2) showed that that 2-amino-4-hydroxy-6-(4-hydroxy-2-oxo-2H-chromen-3-yl)nicotinonitrile 4 exhibited good cytotoxic activity against standard Vinblastine, while the other compounds exhibited moderate cytotoxic activity. Docking simulation showed that2-amino-4-hydroxy-6-(4-hydroxy-2-oxo-2H-chromen-3-yl)nicotinonitrile 4 is an effective inhibitor of the tumor protein HCT-116. A large fluorescence enhancement in a highly acidic medium was observed, and large fluorescence quenching by the addition of traces of Cu²⁺ and Ni²⁺ was also remarked.