Synthesis, antimalarial, antileishmanial evaluation, and molecular docking study of some 3-aryl-2-styryl substituted-4(3H)-quinazolinone derivatives

A progress report in advancements of heterocyclic compounds as novel antimalarial agents over the last 5 years

Malaria, caused by Plasmodium parasites and transmitted by Anopheles mosquitoes, remains a significant global health challenge, especially in tropical and subtropical regions where the disease is endemic. The complex Plasmodium lifecycle, involving stages in both the liver and bloodstream, leads to symptoms such as high fever, anemia, and, in severe cases, life-threatening complications, particularly P. falciparum infections. While historical treatments such as quinine and modern therapies such as artemisinin-based combination therapies (ACTs) have been effective, the growing issue of drug and insecticide resistance undermines these efforts. This resistance has spurred the need for new antimalarial drugs and strategies. Among the promising areas of research are heterocyclic compounds, which, due to their diverse and versatile chemical structures, are being investigated for their ability to disrupt the Plasmodium lifecycle. These compounds have potential as novel therapeutic agents that could enhance current treatment options. Understanding the mechanisms underlying drug resistance and advancing these therapeutic innovations are crucial for maintaining effective malaria control and treatment, highlighting the importance of on-going research in this field.

Recent advances in quinazolinone derivatives: structure, design and therapeutic potential

Quinazolinones, a prominent class of heterocyclic compounds, have garnered significant attention due to their diverse biological activities and synthetic versatility. Over the past thirty years, extensive research has been conducted to explore their pharmacological potential, making them an essential scaffold in modern medicinal chemistry.This review provides an analysis of the most common synthesis methods employed for the preparation of quinazolinones, highlighting their efficiency and applicability. Furthermore, it presents an in-depth discussion of their broad-spectrum biological activities, including anticancer, antimicrobial, antifungal, anti-inflammatory, anticonvulsant, anti-Alzheimer's, antiparasitic, antioxidant, antidiabetic, and antiviral properties. By summarizing the latest advancements in quinazolinone research, specifically those made in the past five years, this review aims to serve as a valuable resource for researchers, facilitating easy access to recent studies and promoting further advancements in the field.

Design, Characterization, Antimicrobial Activity, and In Silico Studies of Theinothiazoloquinazoline Derivatives Bearing Thiazinone, Tetrazole, and Triazole Moieties

The pressing demand for novel antibiotics to counter drug-resistant bacteria, such as methicillin-resistant Staphylococcus aureus (MRSA), underscores the serious public health threat posed by antibiotic resistance. To address this issue, novel quinazoline-4-one derivatives were developed, synthesized, and evaluated in vitro against a range of pathogens, including fungi like Aspergillus fumigatus (RCMB 002008), Gram-negative bacteria like Escherichia coli (ATCC 25922), and Gram-positive bacteria like Staphylococcus aureus (ATCC 25923) and MRSA (USA300). Notably, the thieno-thiazolo-quinazoline compounds 4 and 5 demonstrated a strong ability to inhibit and disrupt MRSA USA300 biofilm formation across all tested concentrations. Furthermore, in an in vivo MRSA skin infection model, these compounds effectively reduced bacterial counts compared to both vehicle-treated and untreated control groups. To enhance understanding and provide deeper insights, ADMET and docking simulations were also conducted.

Quinazolinones as Potential Anticancer Agents: Synthesis and Action Mechanisms

Quinazolinones, essential quinazoline derivatives, exhibit diverse biological activities with applications in pharmaceuticals and insecticides. Some derivatives have already been developed as commercial drugs. Given the rising cancer incidence, there is a critical need for new anticancer agents, and quinazolinones show promising potential in this domain. The present review focuses on novel advances in the synthesis of these important scaffolds and other medicinal aspects involving drug design, the structure-activity relationship, and action mechanisms of quinazoline and quinazolinone derivatives, to help in the development of new quinazoline and quinazolinone derivatives.

In Vitro and In Silico Assessment of Antileishmanial Potential of Novel Tri- and Penta-Valent Antimony Complexes With Phenolic Ligands

Leishmaniasis, caused by protozoan parasites of the genus Leishmania, affects nearly 12 million people annually worldwide, and has limited, highly toxic therapeutic options. This study reports the synthesis, in vitro and in silico evaluations of four novel antimony complexes (3a-3d) as potent and safe antileishmanial agents. The complexes were synthesized using Sb-salts with different phenolic ligands and characterized by elemental analysis, FT-IR and NMR spectroscopic techniques. Structural parameters were further evaluated via DFT studies. The antileishmanial activity of these complexes (3a-3d) was assessed in vitro against promastigote and axenic amastigote forms of Leishmania tropica, showing promising potential as antileishmanial agents. Complex 3a and 3c were particularly active, with IC50 values of 10.8 ± 2.1 and 11.0 ± 2.0 μmol/L against promastigotes, and 20.14 ± 6.11 and 27.72 ± 0.13 μmol/L against amastigotes, respectively. Molecular docking analysis against receptor protein (PDB ID: 8FI6) from genus Leishmania revealed high binding conformations of synthesized molecules within the active cavity of the target protein. With the lowest Ki value of 1.25 and a pattern of hydrophobic π-interactions and strong conventional hydrogen bonds, complex 3d demonstrated excellent binding affinities within the active pocket. Notably, these complexes exhibited low cytotoxicity, compared to the standard antileishmanial drugs, TA (potassium antimonyl tartrate) and AmB (Amphotericin B), with hemolysis rates of < 12% for all complexes. Our findings suggest that these complexes (3a-3d) are promising candidates for the development of new, safer antileishmanial therapies, combining potent activity against L. tropica with significantly lower cytotoxicity compared to existing treatments.

Green Synthetic and Pharmacological Developments in the Hybrid Quinazolinone Moiety: An Updated Review

Bicyclic quinazolinone constitutes an important class of organic framework enveloping numerous biological properties which enthused organic and medicinal chemists to explore green synthetic strategies for the construction of quinazolinone hybrids with significantly improved pharmacodynamics and pharmacokinetic profiles. In this perspective, the present review summarizes the most recent green synthetic strategies, biological properties, structure-activity relationship, and molecular docking studies of the 4-quinazolinone-based scaffold. This review provides deeper insight into the hit-to-lead synthesis of quinazolinone derivatives in the development of clinically important therapeutic candidates.

Halogen-based quinazolin-4(3H)-one derivatives as MCF-7 breast cancer inhibitors: Current developments and structure-activity relationship

Currently, cancer is a serious health challenge with predominance beyond restrictions. Breast cancer remains one of the major contributors to cancer-related morbidity and mortality in women. Chemotherapy continues to be crucial in the treatment of all variants of cancer. Several antitumor drugs are presently in different phases of clinical trials, whereas many more have been approved for clinical use. However, these drugs have the potential to cause adverse effects, and certain individuals may become resistant to them, which would eventually reduce the drug's efficacy. Therefore, it is essential to discover, develop, and improve newer anticancer drug molecules that could potentially inhibit proliferative pathways. In recent years, quinazolinone derivatives, more specifically halogen-substituted 4(3H)-quinazolinone, have drawn attention as a promising new class of chemotherapeutic agents. In addition, these molecules showed significant inhibition in micromolar ranges when tested in vitro against the MCF-7 cell line. Therefore, this study aims to emphasize the intriguing versatility of halogen atoms, providing an in-depth summary and highlighting recent developments in the anticancer properties of halogenated 4(3H)-quinazolinones. It also features a detailed discussion of the structure-activity relationship (SAR) of various functional groups and their interaction with amino acid residues utilizing molecular docking studies. The intent is to foster novel discoveries that can inspire innovative investigations in this domain. Hence, this study simplifies the drug design and development strategies by prolonging the array of pharmacologically active candidates.

Exploring the Recent Pioneering Developments of Small Molecules in Antimalarial Drug Armamentarium: A Chemistry Prospective Appraisal

Malaria is a very destructive and lethal parasitic disease that causes significant mortality worldwide, resulting in the loss of millions of lives annually. It is an infectious disease transmitted by mosquitoes, which is caused by different species of the parasite protozoan belonging to the genus Plasmodium. The uncontrolled intake of antimalarial drugs often employed in clinical settings has resulted in the emergence of numerous strains of plasmodium that are resistant to these drugs, including multidrug-resistant strains. This resistance significantly diminishes the effectiveness of many primary drugs used in the treatment of malaria. Hence, there is an urgent need for developing unique classes of antimalarial drugs that function with distinct mechanisms of action. In this context, the design and development of hybrid compounds that combine pharmacophoric properties from different lead molecules into a single unit gives a unique perspective towards further development of malaria drugs in the next generation. In recent years, the field of medicinal chemistry has made significant efforts resulting in the discovery and synthesis of numerous small novel compounds that exhibit potent antimalarial properties, while also demonstrating reduced toxicity and desirable efficacy. In light of this, we have reviewed the progress of hybrid antimalarial agents from 2021 up to the present. This manuscript presents a comprehensive overview of the latest advancements in the medicinal chemistry pertaining to small molecules, with a specific focus on their potential as antimalarial agents. As possible antimalarial drugs that might target both the dual stage and multi-stage stages of the parasite life cycle, these small hybrid molecules have been studied. This review explores a variety of physiologically active compounds that have been described in the literature in order to lay a strong foundation for the logical design and eventual identification of antimalarial drugs based on lead frameworks.

Synthesis, antileishmanial, antimalarial evaluation and molecular docking study of some hydrazine-coupled pyrazole derivatives

Pyrazole-bearing compounds are known for their diverse pharmacological effects including potent antileishmanial and antimalarial activities. Herein, some hydrazine-coupled pyrazoles were successfully synthesized and their structures were verified by employing elemental microanalysis, FTIR, and 1H NMR techniques. The in vitro antileishmanial and in vivo antimalarial activities of the synthesized pyrazole derivatives (9-15) were evaluated against Leishmania aethiopica clinical isolate and Plasmodium berghei infected mice, respectively. The result revealed that compound 13 displayed superior antipromastigote activity (IC50 = 0.018) that was 174- and 2.6-fold more active than the standard drugs miltefosine (IC50 = 3.130) and amphotericin B deoxycholate (IC50 = 0.047). The molecular docking study conducted on Lm-PTR1, complexed with Trimethoprim was acquired from the Protein Data Bank (PDB ID:2bfm), justified the better antileishmanial activity of compound 13. Furthermore, the target compounds 14 and 15 elicited better inhibition effects against Plasmodium berghei with 70.2% and 90.4% suppression, respectively. In conclusion, the hydrazine-coupled pyrazole derivatives may be considered potential pharmacophores for the preparation of safe and effective antileishmanial and antimalarial agents.

Synthetic product-based approach toward potential antileishmanial drug development

Leishmaniasis is a parasitic disease and is categorized as a tropically neglected disease (NTD) with no effective vaccines available. The available chemotherapeutics against leishmaniasis are associated with an increase in the incidence of toxicity and drug resistance. Consequently, targeting metabolic pathways and enzymes of parasites which differs from the mammalian host can be exploited to treat and overcome the resistance. The classical methods of identifying the structural fragments and the moieties responsible for the biological activities from the standard compounds and their modification are options for developing more effective novel compounds. Significant progress has been made in refining the development of potent non-toxic molecules and addressing the limitations of the current treatment available. Several examples of synthetic product-based approach utilizing their core heterocyclic rings including furan, pyrrole, thiazole, imidazole, pyrazole, triazole, quinazoline, quinoline, pyrimidine, coumarin, indole, acridine, oxadiazole, purine, chalcone, carboline, phenanthrene and metal containing derivatives and their structure-activity relationships are discussed in this review. It also analyses the groups/fragments interacting with the host cell receptors and will support the medicinal chemists with novel antileishmanial agents.

Naphthyl bearing 1,3,4-thiadiazoleacetamides targeting the parasitic folate pathway as anti-infectious agents: in silico, synthesis, and biological approach

Malaria is still a complex and lethal parasitic infectious disease, despite the availability of effective antimalarial drugs. Resistance of malaria parasites to current treatments necessitates new antimalarials targeting P. falciparum proteins. The present study reported the design and synthesis of a series of a 2-(4-substituted piperazin-1-yl)-N-(5-((naphthalen-2-yloxy)methyl)-1,3,4-thiadiazol-2-yl)acetamide hybrids for the inhibition of Plasmodium falciparum dihydrofolate reductase (PfDHFR) using computational biology tools followed by chemical synthesis, structural characterization, and functional analysis. The synthesized compounds were evaluated for their in vitro antimalarial activity against CQ-sensitive PfNF54 and CQ-resistant PfW2 strain. Compounds T5 and T6 are the most active compounds having anti-plasmodial activity against PfNF54 with IC50 values of 0.94 and 3.46 μM respectively. Compound T8 is the most active against the PfW2 strain having an IC50 of 3.91 μM. Further, these active hybrids (T5, T6, and T8) were also evaluated for enzyme inhibition assay against PfDHFR. All the tested compounds were non-toxic against the Hek293 cell line with good selectivity indices. Hemolysis assay also showed non-toxicity of these compounds on normal uninfected human RBCs. In silico molecular docking studies were carried out in the binding pocket of both the wild-type and quadruple mutant Pf-DHFR-TS to gain further insights into probable modes of action of active compounds. ADME prediction and physiochemical properties support their drug-likeness. Additionally, they were screened for antileishmanial activity against L. donovani promastigotes to explore broader applications. Thus, this study provides molecular frameworks for developing potent antimalarials and antileishmanial agents.

An Oxidant-Free and Mild Strategy for Quinazolin-4(3H)-One Synthesis via CuAAC/Ring Cleavage Reaction

An oxidant-free and highly efficient synthesis of phenolic quinazolin-4(3H)-ones was achieved by simply stirring a mixture of 2-aminobenzamides, sulfonyl azides, and terminal alkynes. The intermediate N-sulfonylketenimine underwent two nucleophilic additions and the sulfonyl group eliminated through the power of aromatization. The natural product 2-(4-hydroxybenzyl)quinazolin-4(3H)-one can be synthesized on a large scale under mild conditions with this method.

The role of natural anti-parasitic guided development of synthetic drugs for leishmaniasis

Leishmaniasis is a parasitic disease and categorised as a neglected tropical disease (NTD). Each year, between 70,0000 and 1 million new cases are believed to occur. There are approximately 90 sandfly species which can spread the Leishmania parasites (over 20 species) causing 20,000 to 30,000 death per year. Currently, leishmaniasis has no specific therapeutic treatment available. The prescribed drugs with several drawbacks including high cost, challenging administration, toxicity, and drug resistance led to search for the alternative treatment with less toxicity and selectivity. Introducing the molecular features like that of phytoconstituents for the search of compounds with less toxicity is another promising approach. The current review classifies the synthetic compounds according to the core rings present in the natural phytochemicals for the development of antileishmanial agents (2020-2022). Considering the toxicity and limitations of synthetic analogues, natural compounds are at the higher notch in terms of effectiveness and safety. Synthesized compounds of chalcones (Compound 8; IC₅₀: 0.03 μM, 4.7 folds more potent than Amphotericin B; IC₅₀: 0.14 μM), pyrimidine (compound 56; against L. tropica; 0.04 μM and L. infantum; 0.042 μM as compared to glucantime: L. tropica; 8.17 μM and L. infantum; 8.42 μM), quinazoline and (compound 72; 0.021 μM, 150 times more potent than miltefosine). The targeted delivery against DHFR have been demonstrated by one of the pyrimidine compounds 62 with an IC₅₀ value of 0.10 μM against L. major as compared to the standard trimethoprim (IC₅₀: 20 μM). The review covers the medicinal importance of antileishmanial agents from synthetic and natural sources such as chalcone, pyrazole, coumarins, steroids, and alkaloidal-containing drugs (indole, quinolines, pyridine, pyrimidine, carbolines, pyrrole, aurones, and quinazolines). The efforts of introducing the core rings present in the natural phytoconstituents as antileishmanial in the synthetic compounds are discussed with their structural activity relationship. The perspective will support the medicinal chemists in refining and directing the development of novel molecules phytochemicals-based antileishmanial agents.