Synthesis of Triazole Derivatives of 9-Ethyl-9H-carbazole and Dibenzo[b,d]furan and Evaluation of Their Antimycobacterial and Immunomodulatory Activity

Exploration of triazole derivatives, SAR profiles, and clinical pipeline against Mycobacterium tuberculosis

Tuberculosis is a highly infectious disease and it is a global threat in particular affecting people from developing countries. It is thought that nearly one-third of the global population lives with this causative bacterium in its dominant form. The spread of HIV and the development of resistance to both multidrug-resistant TB (MDR-TB) and extensively drug-resistant TB (XDR-TB) aggravates the spread of the disease and needs novel drugs which combat this disease effectively. Triazole-containing anti-tubercular drugs are promising and need further tuning to develop as a potent scaffold for tuberculosis. In this review, we highlight the structural activity relationships of triazole-containing drugs and detailed understanding for the researchers in the field of medicinal chemistry to further explore these triazole-based compounds as well as synthesize new compounds for antitubercular activity against drug-sensitive and resistant strains.

Emerging Aspects of Triazole in Organic Synthesis: Exploring its Potential as a Gelator

Cu(I)-catalyzed azide-alkyne 1,3-dipolar cycloaddition (CuAAC) - commonly known as the "click reaction" - serves as the most effective and highly reliable tool for facile construction of simple to complex designs at the molecular level. It relates to the formation of carbon heteroatomic systems by joining or clicking small molecular pieces together with the help of various organic reactions such as cycloaddition, conjugate addition, ring-opening, etc. Such dynamic strategy results in the generation of triazole and its derivatives from azides and alkynes with three nitrogen atoms in the five-membered aromatic azole ring that often forms gel-assembled structures having gelating properties. These scaffolds have led to prominent applications in designing advanced soft materials, 3D printing, ion sensing, drug delivery, photonics, separation, and purification. In this review, we mainly emphasize the different mechanistic aspects of triazole formation, which includes the synthesis of sugar-based and non-sugar-based triazoles, and their gel applications reported in the literature for the past ten years, as well as the upcoming scope in different branches of applied sciences.

Revolutionizing Tuberculosis Treatment: Uncovering New Drugs and Breakthrough Inhibitors to Combat Drug-Resistant Mycobacterium tuberculosis

Tuberculosis (TB) is a global health threat that causes significant mortality. This review explores chemotherapeutics that target essential processes in Mycobacterium tuberculosis, such as DNA replication, protein synthesis, cell wall formation, energy metabolism, and proteolysis. We emphasize the need for new drugs to treat drug-resistant strains and shorten the treatment duration. Emerging targets and promising inhibitors were identified by examining the intricate biology of TB. This review provides an overview of recent developments in the search for anti-TB drugs with a focus on newly validated targets and inhibitors. We aimed to contribute to efforts to combat TB and improve therapeutic outcomes.

An overview of mechanism and chemical inhibitors of shikimate kinase

Tuberculosis is a highly infectious disease other than HIV/AIDS and it is one of the top ten causes of death worldwide. Resistance development in the bacteria occurs because of genetic alterations, and the molecular insights suggest that the accumulation of mutation in the individual drug target genes is the primary mechanism of multi-drug resistant tuberculosis. Chorismate is an essential structural fragment for the synthesis of aromatic amino acids and synthesized biochemically by a number of bacteria, including Mycobacterium tuberculosis, utilizing the shikimate pathway. This shikimate kinase is the newer possible target for the generation of novel antitubercular drug because this pathway is expressed only in mycobacterium and not in Mammals. The discovery and development of shikimate kinase inhibitors provide an opportunity for the development of novel selective medications. Multiple shikimate kinase inhibitors have been identified via insilico virtual screening and related protein-ligand interactions along with their in-vitro studies. These inhibitors bind to the active site in a similar fashion to shikimate. In the current review, we present an overview of the biology and chemistry of the shikimate kinase protein and its inhibitors, with special emphasis on the various active scaffold against the enzyme. A variety of chemically diversified synthetic scaffolds including Benzothiazoles, Oxadiazoles, Thiobarbiturates, Naphthoquinones, Thiazoleacetonitriles, Hybridized Pyrazolone derivatives, Orthologous biological macromolecule derivatives, Manzamine Alkaloids derivatives, Dipeptide inhibitor, and Chalcones are discussed in detail. These derivatives bind to the specific target appropriately proving their potential ability through different binding interactions and effectively explored as an effective and selective Sk inhibitor.Communicated by Ramaswamy H. Sarma.

An Overview of 1,2,3-triazole-Containing Hybrids and Their Potential Anticholinesterase Activities

Acetylcholine (ACh) neurotransmitter of the cholinergic system in the brain is involved in learning, memory, stress responses, and cognitive functioning. It is hydrolyzed into choline and acetic acid by two key cholinesterase enzymes, viz., acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). A loss or degeneration of cholinergic neurons that leads to a reduction in ACh levels is considered a significant contributing factor in the development of neurodegenerative diseases (NDs) such as Alzheimer's disease (AD). Numerous studies have shown that cholinesterase inhibitors can raise the level of ACh and, therefore, enhance people's quality of life, and, at the very least, it can temporarily lessen the symptoms of NDs. 1,2,3-triazole, a five-membered heterocyclic ring, is a privileged moiety, that is, a central scaffold, and is capable of interacting with a variety of receptors and enzymes to exhibit a broad range of important biological activities. Recently, it has been clubbed with other pharmacophoric fragments/molecules in hope of obtaining potent and selective AChE and/or BuChE inhibitors. The present updated review succinctly summarizes the different synthetic strategies used to synthesize the 1,2,3-triazole moiety. It also highlights the anticholinesterase potential of various 1,2,3-triazole di/trihybrids reported in the past seven years (2015-2022), including a rationale for hybridization and with an emphasis on their structural features for the development and optimization of cholinesterase inhibitors to treat NDs.

Plasmodium falciparum Malaria Vaccines and Vaccine Adjuvants

Malaria-a parasite vector-borne disease-is a global health problem, and Plasmodium falciparum has proven to be the deadliest among Plasmodium spp., which causes malaria in humans. Symptoms of the disease range from mild fever and shivering to hemolytic anemia and neurological dysfunctions. The spread of drug resistance and the absence of effective vaccines has made malaria disease an ever-emerging problem. Although progress has been made in understanding the host response to the parasite, various aspects of its biology in its mammalian host are still unclear. In this context, there is a pressing demand for the development of effective preventive and therapeutic strategies, including new drugs and novel adjuvanted vaccines that elicit protective immunity. The present article provides an overview of the current knowledge of anti-malarial immunity against P. falciparum and different options of vaccine candidates in development. A special emphasis has been made on the mechanism of action of clinically used vaccine adjuvants.

Synthesis, Characterization and Biological Evaluation of New 3,5-Disubstituted-Pyrazoline Derivatives as Potential Anti-Mycobacterium tuberculosis H37Ra Compounds

A total of fourteen pyrazoline derivatives were synthesized through cyclo-condensation reactions by chalcone derivatives with different types of semicarbazide. These compounds were characterized by IR, 1D-NMR (¹H, ¹³C and Distortionless Enhancement by Polarization Transfer - DEPT-135) and 2D-NMR (COSY, HSQC and HMBC) as well as mass spectroscopy analysis (HRMS). The synthesized compounds were tested for their antituberculosis activity against Mycobacterium tuberculosis H37Ra in vitro. Based on this activity, compound 4a showed the most potent inhibitory activity, with a minimum inhibitory concentration (MIC) value of 17 μM. In addition, six other synthesized compounds, 5a and 5c–5g, exhibited moderate activity, with MIC ranges between 60 μM to 140 μM. Compound 4a showed good bactericidal activity with a minimum bactericidal concentration (MBC) value of 34 μM against Mycobacterium tuberculosis H37Ra. Molecular docking studies for compound 4a on alpha-sterol demethylase was done to understand and explore ligand–receptor interactions, and to hypothesize potential refinements for the compound.

Triazole-containing hybrids with anti-Mycobacterium tuberculosis potential - Part I: 1,2,3-Triazole

Tuberculosis regimens currently applied in clinical practice require months of multidrug therapy, which imposes a major challenge of patient compliance and drug resistance development. Moreover, because of the increasing emergence of hard-to-treat tuberculosis, this disease continues to be a significant threat to the human population. 1,2,3-triazole as a privileged structure has been widely used as an effective template for drug discovery, and 1,2,3-triazole-containing hybrids that can simultaneously act on dual or multiple targets in Mycobacterium tuberculosis have the potential to circumvent drug resistance, enhance efficacy, reduce side effects and improve pharmacokinetic as well as pharmacodynamic profiles. Thus, 1,2,3-triazole-containing hybrids are useful scaffolds for the development of antitubercular agents. This review aims to highlight recent advances of 1,2,3-triazole-containing hybrids with potential activity against various forms of M. tuberculosis, covering articles published between 2015 and 2020. The structure-activity relationship and the mechanism of action are also discussed to facilitate further rational design of more effective drug candidates.

New tuberculosis drug targets, their inhibitors, and potential therapeutic impact

The current tuberculosis (TB) predicament poses numerous challenges and therefore every incremental scientific work and all positive socio-political engagements, are steps taken in the right direction to eradicate TB. Progression of the late stage TB-drug pipeline into the clinics is an immediate deliverable of this global effort. At the same time, fueling basic research and pursuing early discovery work must be sustained to maintain a healthy TB-drug pipeline. This review encompasses a broad analysis of chemotherapeutic strategies that target the DNA replication, protein synthesis, cell wall biosynthesis, energy metabolism and proteolysis of Mycobacterium tuberculosis (Mtb). It includes a status check of the current TB-drug pipeline with a focus on the associated biology, emerging targets, and their promising chemical inhibitors. Potential synergies and/or gaps within or across different chemotherapeutic strategies are systematically reviewed as well.