Design and synthesis of phenoxy methyl-oxadiazole compounds against Alzheimer's disease

This study examines the synthesis and evaluation of 11 newly developed compounds as potential anti-Alzheimer's agents that occur via cholinesterase and β-secretase inhibition. The compounds were tested for their inhibitory activity against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) using the modified Ellman method. The results showed that several compounds exhibited significant inhibition of AChE, particularly compounds 6d, 7a, and 7e, which demonstrated high inhibitory activity at lower concentrations, with IC50 values of 0.120, 0.039, and 0.063 µM, respectively. However, the compounds showed limited effectiveness against BChE, with only a few compounds exhibiting moderate inhibition. Compound 7e showed an inhibitory effect against BACE-1 close to that of the standard drug. Structural analysis revealed that the compounds with substituted benzothiazole and thiazole moieties exhibited the most promising inhibitory activity. This study provides valuable insights into the potential of these synthesized derivatives as a treatment against Alzheimer's disease. Moreover, the structure, stability, and properties of the active compounds were further investigated using density functional theory calculations. As a final note, the utilization of molecular docking and molecular dynamics simulation studies allowed us to elucidate the action mechanism of the active compounds and gain insights into the structure-activity relationship against AChE and β-secretase proteins. These computational techniques provide valuable information on the binding modes, interactions with target enzymes, dynamic behavior, and conformational changes of the compounds, enabling a comprehensive understanding of their biological activity.

Design, synthesis and molecular docking study of novel triazole-quinazolinone hybrids as antimalarial and antitubercular agents

In a quest to discover new antimalarial and antitubercular drugs, we have designed and synthesized a series of novel triazole-quinazolinone hybrids. The in vitro screening of the triazole-quinazolinone hybrid entities against the plasmodium species P. falciparum offered potent antimalarial molecules 6c, 6d, 6f, 6g, 6j & 6k owing comparable activity to the reference drugs. Furthermore, the target compounds were evaluated in vitro against Mycobacterium tuberculosis (MTB) H37Rv strain. Among the screened compounds, 6c, 6d and 6l were found to be the most active molecules with a MIC values of 19.57-40.68 μM. The cytotoxicity of the most active compounds was studied against RAW 264.7 cell line by MTT assay and no toxicity was observed. The computational study including drug likeness and ADMET profiling, DFT, and molecular docking study was done to explore the features of target molecules. The compounds 6a, 6g, and 6k exhibited highest binding affinity of -10.3 kcal/mol with docked molecular targets from M. tuberculosis. Molecular docking study indicates that all the molecules are binding to the falcipain 2 protease (PDB: 6SSZ) of the P. falciparum. Our findings indicated that these new triazole-quinazolinone hybrids may be considered hit molecules for further optimization studies.

Synthesis, biological evaluation and molecular docking study of pyrimidine linked thiazolidinedione derivatives as potential antimicrobial and antitubercular agents

The design and development of novel antimicrobial agents are highly desired to combat the emergence of medication resistance against microorganisms that cause infections. A series of new pyrimidine-linked thiazolidinedione derivatives (5a-j) were synthesized, characterized, and their antimicrobial properties assessed in the current investigation. Here, novel pyrimidine-linked thiazolidinedione compounds were designed using the molecular hybridization approach. Elemental and spectral techniques were used to determine the structures of the synthesized hybrids. The majority of compounds showed encouraging antibacterial properties. Among the active compounds, 5g, 5i, and 5j showed 1.85, 1.15, and 1.38 times the activity of streptomycin against S. aureus, respectively, with MIC values of 6.4, 10.3, and 8.6 µM. With MIC values of 10.8, 21.9, and 15.4 µM, respectively, the compounds 5g, 5i, and 5j showed 2.14, 1.05, and 1.50 times the activity of linezolid against the methicillin-resistant S. aureus (MRSA) strain. Furthermore, when compared to the reference medications, compounds 5g, 5i, and 5j demonstrated broad-range antimicrobial efficacy against all tested strains of bacteria and fungus. Out of all the compounds that were investigated, compounds 5g, 5i, and 5j showed noteworthy anti-tubercular activity. 5g is the most effective, 1.59 times more effective than reference drug isoniazid. To anticipate the binding manner, the synthesized potent compounds were subjected to molecular docking into the active binding site of MRSA and the mycobacterial membrane protein large 3 (MmpL3) protein. The compounds 5g, 5i, and 5j may eventually serve as lead compounds in the search for antimicrobial and anti-TB therapeutic agents.

In silico drug design strategies for discovering novel tuberculosis therapeutics

INTRODUCTION

Tuberculosis remains a significant concern in global public health due to its intricate biology and propensity for developing antibiotic resistance. Discovering new drugs is a protracted and expensive endeavor, often spanning over a decade and incurring costs in the billions. However, computer-aided drug design (CADD) has surfaced as a nimbler and more cost-effective alternative. CADD tools enable us to decipher the interactions between therapeutic targets and novel drugs, making them invaluable in the quest for new tuberculosis treatments.

AREAS COVERED

In this review, the authors explore recent advancements in tuberculosis drug discovery enabled by in silico tools. The main objectives of this review article are to highlight emerging drug candidates identified through in silico methods and to provide an update on the therapeutic targets associated with Mycobacterium tuberculosis.

EXPERT OPINION

These in silico methods have not only streamlined the drug discovery process but also opened up new horizons for finding novel drug candidates and repositioning existing ones. The continued advancements in these fields hold great promise for more efficient, ethical, and successful drug development in the future.

Synthesis, antitubercular profile and molecular docking studies of quinazolinone-based pyridine derivatives against drug-resistant tuberculosis

The promising quinazolinone-based pyridine derivatives (4a-j) were synthesized and subsequently tested for their antimycobacterial activities against the various drug-sensitive and drug-resistant Mycobacterium tuberculosis (Mtb) strains to combat infectious diseases and address growing concerns about the devastating effects of tuberculosis (TB). Utilizing 1H NMR, 13C NMR, and mass spectra, the structural and molecular confirmation of the synthesized compounds were deciphered. With minimum inhibitory concentration (MIC) values ranging from 0.31 to 19.13 μM, the results showed that compounds 4e and 4f showed promise anti-TB action against both drug-sensitive and drug-resistant TB strains. To study the cytotoxicity of synthesized molecules, normal Vero and mouse macrophage (RAW264.7) cell lines were utilized. Remarkably, it was revealed that at the highest concentration tested, none of the newly synthesized molecules were toxic to the Vero cell line. The binding patterns of the potent compounds 4b, 4e and 4f in the active site of the mycobacterial membrane protein Large 3 (MmpL3) protein are also revealed by molecular docking studies, which has contributed to the development of a structural rationale for Mtb inhibition. The physicochemical characteristics of the compounds were then predicted using theoretical calculations. Overall, the molecular docking results, physiochemical properties, and observed antimycobacterial activity all point to compound 4e with trifluoromethyl and compound 4f with nitro moiety as potential quinazolinone linked pyridine-based MmpL3 inhibitors.Communicated by Ramaswamy H. Sarma.

In Silico and In Vitro Analyses to Repurpose Quercetin as a Human Pancreatic α-Amylase Inhibitor

Human pancreatic α-amylase (HPA), situated at the apex of the starch digestion hierarchy, is an attractive therapeutic approach to precisely regulate blood glucose levels, thereby efficiently managing diabetes. Polyphenols offer a natural and multifaceted approach to moderate postprandial sugar spikes, with their slight modulation in carbohydrate digestion and potential secondary benefits, such as antioxidant and anti-inflammatory effects. Taking into consideration the unfavorable side effects of currently available commercial medications, we aimed to study a library of polyphenols attributed to their remarkable antidiabetic properties and screened the most potent HPA inhibitor via a comprehensive in silico study encompassing molecular docking, molecular mechanics with generalized Born and surface area solvation (MM/GBSA) calculation, molecular dynamics (MD) simulation, density functional theory (DFT) study, and pharmacokinetic properties followed by an in vitro assay. Significant hydrogen bonding with the catalytic triad residues of HPA, prominent MM/GBSA binding energy of -27.03 kcal/mol, and the stable nature of the protein-ligand complex with regard to 100 ns MD simulation screened quercetin as the best HPA inhibitor. Additionally, quercetin showed strong reactivity in the substrate-binding pocket of HPA and exhibited favorable pharmacokinetic properties with a considerable inhibitory concentration (IC50) of 57.37 ± 0.9 μg/mL against α-amylase. This study holds prospects for HPA inhibition and suggests quercetin as an approach to therapy for diabetes; however, it is imperative to conduct further research.

DNA groove binder and significant cytotoxic activity on human colon cancer cells: Potential of a dimeric zinc (II) phthalocyanine derivative

The interaction of a multi-component system consisting of benzene-1,4-diyldimethanimine-bridged dimeric zinc-phthalocyanine groups (4OMPCZ) with calf thymus DNA (ct-DNA) was investigated using UV-Vis absorption, fluorescence emission spectroscopy methods, and viscosity measurements. The binding constant, K_b, which is an important parameter to gain information about the binding mode, was found as 9.7 × 10⁷ M^-1 from the UV-Vis absorption studies. Another important spectrophotometric tool is competitive displacement assays with Ethidium bromide and Hoechst 33342. Through this experiment, a higher K_SV value was obtained with Hoechst for the phthalocyanine derivative, 4OMPCZ, and the ct-DNA complex than with ethidium bromide. Additionally, molecular docking studies were conducted to calculate the theoretical binding constant and visualize the interactions of 4OMPCZ with a model DNA. According to docking results, although the interactions are mainly located in the major groove of the DNA helix, due to the wrapping, these interactions can also be extended to the minor groove of the DNA. Spectrophotometric, molecular docking, and viscosity studies revealed that the interaction of 4OMPCZ with DNA is likely to be via the major and minor grooves. The in vitro cytotoxic activity of 4OMPCZ was evaluated by MTT assay on human colon cancer cells (HT29) after 72 h of treatment. 4OMPCZ indicated significant cytotoxic activity when stimulated with UV light compared to the standard chemotherapy drugs, fluorouracil (5-FU), and cisplatin on HT29 colon cancer cells. The IC₅₀ value of 4OMPCZ displayed considerably lower concentrations compared to the standard drugs, 5-FU, and cisplatin.

Microwave-assisted N-alkylation of amines with alcohols catalyzed by MnCl2 : Anticancer, docking, and DFT studies

A new protocol for the N-alkylation of amines with alcohols for the synthesis of tertiary amines in the presence of MnCl₂ as a catalyst, under microwave conditions, is described. The advantages of this protocol include stable reaction profiles, a wide substrate variety, excellent yields, low cost, high yields, and easy workup conditions. The anticancer efficacy of all the synthesized compounds was tested in vitro against various cancer cell lines, such as MCF-7, MDA-MB-231 (human breast), HT-29, HCT 116 (colon cancer), A549 (human lung carcinoma), and Vero cells. Among the screened compounds, 3e, 3h, and 3i demonstrated potent anticancer activity, with compound 3h surpassing the reference drug cisplatin against A549, MCF7, MDA-MB-231, and HCT116 cancer cells. The introduction of an electron-withdrawing group on the phenyl ring resulted in increased anticancer activity. The most potent compounds, 3e, 3h, and 3i, were tested against VEGFR-2, HER2, and EGFR in multikinase inhibition assays, with compounds 3h and 3i showing improved potency against the HER2 kinase. The compounds formed two H-bonds with amino acids, indicating that they had a high affinity for the target HER2 kinase (PDB ID: 3RCD), according to the docking analysis. The absorption, distribution, metabolism, excretion, and toxicity properties of the optimized analogs were also assessed in vitro, enabling the discovery of promising anticancer agents. Finally, the B3LYP level was used to measure density functional theory geometry optimization and the related quantum parameters for the active compounds.

Design, synthesis and molecular docking studies of imidazole and benzimidazole linked ethionamide derivatives as inhibitors of InhA and antituberculosis agents

To explore effective antituberculosis agents, a new class of imidazoles and benzimidazoles linked ethionamide analogs were designed and synthesized. The elemental analysis, ¹H NMR, ¹³C NMR and mass spectral data were used to characterize all of the novel analogs. In vitro activity against Mycobacterium tuberculosis (Mtb) H37Rv was assessed for all of the target compounds. The hydroxy and nitrile moieties on the imidazole ring, as well as the hydroxy and methoxy groups on the benzimidazole ring connected to the ethionamide side chain, were shown to be advantageous. In our cell viability experiment against the Vero cell line, all of the compounds were non-cytotoxic even at 100 μM. To confirm the powerful analogs target identification, we investigated their in vitro inhibitory action on an M. tuberculosis InhA over-expressing (Mtb InhA-OE) strain, which yielded MICs nearly twice those of the Mtb H37Rv strain. Furthermore, the results of molecular docking confirmed the experimental findings. Additionally, the molecules were evaluated in silico for ADMET and drug similarity features. The experimental observation enables the newly generated ethionamide derivatives to be attractive candidates for the creation of newer and better anti-TB agents.

Discovery of a novel series of substituted quinolines acting as anticancer agents and selective EGFR blocker: Molecular docking study

A Ta₂O₅-anchored-piperidine-4-carboxylic acid (PPCA) nanoparticle has been synthesized and characterized. It was then used as a highly effective nanocatalyst for the synthesis of quinolin-2(1H)-one derivatives through CO bond functionalization. The special advantage of this heterogeneous solid catalyst is the reusability of the catalyst for up to five cycles without any noticeable reduction in product yields. In comparison, healthy reaction profiles, wide substrate scope, excellent yields and easy workup conditions are the notable highlights of this approach. All the compounds were tested for their anticancer activity against MCF-7 (human breast), HepG2 (human liver), HCT116 (human colorectal), and PC-3 (human prostate) cancer cell lines with the MTT assay. All the compounds were shown to have moderate to good inhibitory effects on tested cancer cell lines. Besides, compounds 5b, 5c and 5d showed good selectivity against epidermal growth factor receptor-tyrosine kinase (EGFR-TK). Molecular docking results showed that active compounds showed a good affinity towards EGFR kinase (PDB ID: 6V6O) by forming two hydrogen bonds with Cys-797 and Tyr-801. All the compounds were screened for computational ADMET and Lipinski analysis.

Anti-obesity, antioxidant and in silico evaluation of Justicia carnea bioactive compounds as potential inhibitors of an enzyme linked with obesity: Insights from kinetics, semi-empirical quantum mechanics and molecular docking analysis

Obesity is a global health problem characterized by excessive fat deposition in adipose tissues and can be managed by targeting pancreatic lipase (PL) activity. In the present study, we investigated the in vitro antioxidant and anti-obesity potentials of methanolic leaf extract of Justicia carnea(MEJC) using lipase inhibition kinetics model. In silico evaluations of MEJC bioactive compounds as potential drug-like agents and inhibitors of PL were also investigated using SwissADME prediction tool, semi-empirical quantum mechanics(SQM), molecular electrostatic potential(MEP) and molecular docking analysis. Gas chromatography-mass spectrometry(GC-MS) revealed presence of campesterol, stigmasterol, beta-amyrin etc. MEJC scavenged reactive species and inhibited PL activity via a mixed inhibition pattern (K_i = 107.69 μg/mL; K_ii = 398.00 μg/mL) with IC₅₀ > orlistat's IC₅₀. Molecular docking of GC-MS identified compounds with porcine PL showed compounds 8,10,12 and 14 having high PL-binding affinity and similar binding pose with orlistat. Hydrophobic interactions and van der Waals forces were predominantly involved in the ligands' interactions with some key catalytic site amino acid residues (Ser-153,His-264). Compounds 10,12,13 and 14 indicated high drug-likeness, bioavailability, electronegativity, E_LUMO-E_HOMO energy gaps and MEP. Our findings show that MEJC is a rich natural source of antioxidant and anti-obesity agents which could be optimized for development of new anti-obesity drugs.

Neto JDB, de Abreu FC, Figueiredo IM, Carinhanha C. Santos J, Pessoa CDÓ, da Silva-Júnior EF, de Araújo-Júnior JX, M. de Aquino T. Synthesis of hybrids thiazole–quinoline, thiazole–indole and their analogs: in vitro anti-proliferative effects on cancer cell lines, DNA binding properties and molecular modeling

A quinoline–thiazole hybrid was synthesized, which showed cytotoxicity against the HL-60 cell line. Electrochemical and spectroscopic experiments suggested DNA as the biological target.

Novel 1,3,5-triazine-based pyrazole derivatives as potential antitumor agents and EFGR kinase inhibitors: synthesis, cytotoxicity, DNA binding, molecular docking and DFT studies

The development of new 1,3,5-triazine-based pyrazole derivatives as effective anticancer agents.