Linking azoles to isoniazid via hydrazone bridge: Synthesis, crystal structure determination, antitubercular evaluation and computational studies

In vitro and in silico analysis of synthesized N-benzyl indole-derived hydrazones as potential anti-triple negative breast cancer agents

Triple-negative breast cancer (TNBC) is one of the most aggressive forms of breast cancer, and it is characterized by a high recurrence rate and the rapid development of drug resistance across various subtypes. Currently, there is no targeted therapy, which is specifically approved for the treatment of TNBC. In this study, we synthesized a series of N-benzyl indole-3-carboxaldehyde-based hydrazones and subjected them to in vitro anticancer studies on MCF-10A and MDA-MB-231 breast cancer (BC) cell lines. Our in vitro results suggested that all the compounds exhibited significant anti-TNBC activity, especially on MDA-MB-231 cells. Compound 5b showed excellent activity on MDA-MB-231 (IC50 = 17.2 ± 0.4 nM). Furthermore, molecular docking analysis revealed that this compound had a higher binding affinity towards the target EGFR (epidermal growth factor receptor) with a docking score of -10.523 kcal mol-1. The molecular dynamics simulation of complex 5b:3W2S showed stable binding over a period of 100 ns. A detailed multi-linear regression (MLR) QSAR denoted the importance of key molecular descriptors, such as com_accminus_2A, fringNlipo6A, and sp3Cplus_AbSA. These analyses indicate that the synthesized compounds deserve further studies for developing novel and more potent candidates against triple-negative breast cancer.

Functionalized regioisomers of the natural product phenazines myxin and iodinin as potent inhibitors of Mycobacterium tuberculosis and human acute myeloid leukemia cells

The natural bioactive products myxin and iodinin are phenazine 5,10-dioxides possessing potent anti-bacterial and anti-cancer activity in vitro. This work describes the synthesis and derivatization of new myxin and iodinin regioisomers, developed from 1,3-dihydroxyphenazine 5,10-dioxide. Compounds were evaluated for activity towards M. tuberculosis (Mtb) strains, a human AML cell line (MOLM-13), and two non-cancerous mammalian cell lines (NRK and H9c2). Highly potent analogs were developed having IC50 values against MTB down to 20 nM and 1.4 μM for human AML cells. 1-OH-3-O-alkyl substituted derivatives demonstrated high efficacy against Mtb and low toxicity in normal cells. 2,3-substituted regioisomers of myxin and iodinin were shown to be inactive, highlighting the importance of oxygen substituent in position 1 of the scaffold. A strong positive correlation between anti-MTB and anti-AML activity was revealed, suggesting a common mechanism of action in bacteria and cancer cells. These findings demonstrate the therapeutic potential of 1,3-O-functionalized phenazine 5,10-dioxides in chemotherapy for Mtb and AML and contribute to the structure-activity understanding of phenazine 5,10-dioxides with respect to their biological activity.

Hydrazones, hydrazones-based coinage metal complexes, and their biological applications

Hydrazone-based compounds distinguished by their azomethine -NHN[double bond, length as m-dash]CH group and their respective coinage metal complexes have emerged as leading candidates in the search for effective anticancer and antibiotic agents. Because of their varied pharmacological potential and simplicity of synthesis, these compounds have been the subject of substantial research. Hydrazones exhibit versatile coordination chemistry, allowing for the formation of stable complexes with metals such as copper, silver, and gold. Hydrazone derivatives and their metal complexes demonstrate significant biological activities, displaying potent anticancer properties inducing apoptosis, inhibiting cell proliferation, and disrupting angiogenesis. Furthermore, they exhibit vigorous antibiotic activity by compromising microbial cell membranes and inhibiting essential enzymes. This review article highlights the versatility and effectiveness of hydrazone-based compounds and their coinage metal complexes reported for the last five years, underscoring their potential as next-generation diagnostic and therapeutic agents. Ongoing research focuses on optimizing these compounds for more excellent selectivity, potency, and biocompatibility, which is expected to advance their practical biological applications.

In silico development of potential InhA inhibitors through 3D-QSAR analysis, virtual screening and molecular dynamics

Tuberculosis is one of the most ancient infectious diseases known to mankind predating upper Paleolithic era. In the current scenario, treatment of drug resistance tuberculosis is the major challenge as the treatment options are limited, less efficient and more toxic. In our study we have developed an atom based 3D QSAR model, statistically validated sound with R2 > 0.90 and Q2 > 0.72 using reported direct inhibitors of InhA (2018-2022), validated by enzyme inhibition assay. The model was used to screen a library of 3958 molecules taken from Binding DB and candidates molecules with promising predicted activity value (pIC50) > 5) were selected for further analyzed screening by using molecular docking, ADME profiling and molecular dynamic simulations. The lead molecule, ZINC11536150 exhibited good docking score (glideXP = -11.634 kcal/mol) compared to standard triclosan (glideXP =  -7.129 kcal/mol kcal/mol) and through molecular dynamics study it was observed that the 2nv6-complex of ZINC11536150 with Mycobacterium tuberculosis InhA (PDB entry: 2NV6) complex remained stable throughout the entire simulation time of 100 ns.Communicated by Ramaswamy H. Sarma.

Activity against Mycobacterium tuberculosis of a new class of spirooxindolopyrrolidine embedded chromanone hybrid heterocycles

A new class of structurally intriguing heterocycles embedded with spiropyrrolidine, oxindole and chromanones was prepared by regio- and stereoselectively in quantitative yields using an intermolecular tandem cycloaddition protocol. The compounds synthesized were assayed for their anti-mycobacterial activity against Mycobacterium tuberculosis (Mtb) H37Rv and isoniazid-resistant (katG and inhA promoter mutations) clinical Mtb isolates. Four compounds exhibited significant antimycobacterial activity against Mtb strains tested. In particular, a compound possessing a fluorine substituted derivative displayed potent activity at 0.39 μg mL-1 against H37Rv, while it showed 0.09 μg mL-1 and 0.19 μg mL-1 activity against inhA promoter and katG mutation isolates, respectively. A molecular docking study was conducted with the potent compound, which showed results that were consistent with the in vitro experiments.

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.

Recent Advances in Anti-Tuberculosis Drug Discovery Based on Hydrazide-Hydrazone and Thiadiazole Derivatives Targeting InhA

Tuberculosis is an extremely serious problem of global public health. Its incidence is worsened by the presence of multidrug-resistant (MDR) strains of Mycobacterium tuberculosis. More serious forms of drug resistance have been observed in recent years. Therefore, the discovery and/or synthesis of new potent and less toxic anti-tubercular compounds is very critical, especially having in mind the consequences and the delays in treatment caused by the COVID-19 pandemic. Enoyl-acyl carrier protein reductase (InhA) is an important enzyme involved in the biosynthesis of mycolic acid, a major component of the M. tuberculosis cell wall. At the same time, it is a key enzyme in the development of drug resistance, making it an important target for the discovery of new antimycobacterial agents. Many different chemical scaffolds, including hydrazide hydrazones and thiadiazoles, have been evaluated for their InhA inhibitory activity. The aim of this review is to evaluate recently described hydrazide-hydrazone- and thiadiazole-containing derivatives that inhibit InhA activity, resulting in antimycobacterial effects. In addition, a brief review of the mechanisms of action of currently available anti-tuberculosis drugs is provided, including recently approved agents and molecules in clinical trials.

Isoniazid Linked to Sulfonate Esters via Hydrazone Functionality: Design, Synthesis, and Evaluation of Antitubercular Activity

Isoniazid (INH) is one of the key molecules employed in the treatment of tuberculosis (TB), the most deadly infectious disease worldwide. However, the efficacy of this cornerstone drug has seriously decreased due to emerging INH-resistant strains of Mycobacterium tuberculosis (Mtb). In the present study, we aimed to chemically tailor INH to overcome this resistance. We obtained thirteen novel compounds by linking INH to in-house synthesized sulfonate esters via a hydrazone bridge (SIH1-SIH13). Following structural characterization by FTIR, ¹H NMR, ¹³C NMR, and HRMS, all compounds were screened for their antitubercular activity against Mtb H37Rv strain and INH-resistant clinical isolates carrying katG and inhA mutations. Additionally, the cytotoxic effects of SIH1-SIH13 were assessed on three different healthy host cell lines; HEK293, IMR-90, and BEAS-2B. Based on the obtained data, the synthesized compounds appeared as attractive antimycobacterial drug candidates with low cytotoxicity. Moreover, the stability of the hydrazone moiety in the chemical structure of the final compounds was confirmed by using UV/Vis spectroscopy in both aqueous medium and DMSO. Subsequently, the compounds were tested for their inhibitory activities against enoyl acyl carrier protein reductase (InhA), the primary target enzyme of INH. Although most of the synthesized compounds are hosted by the InhA binding pocket, SIH1-SIH13 do not primarily show their antitubercular activities by direct InhA inhibition. Finally, in silico determination of important physicochemical parameters of the molecules showed that SIH1-SIH13 adhered to Lipinski's rule of five. Overall, our study revealed a new strategy for modifying INH to cope with the emerging drug-resistant strains of Mtb.