Pyrazole and pyrazoline derivatives as antimalarial agents: A key review

Design, synthesis and biological evaluation of new class of pyrazoles-dihydropyrimidinone derivatives as bone anabolic agents

This study explores a series of twenty-four newly synthesized pyrzole-dihydropyrimidinone hybrids as potential bone anabolic agents. Initially, an alkaline phosphatase assay, a common marker of bone formation, was used to screen all compounds for their ability to stimulate osteogenic potential. Initial screening identified three promising candidates (5f, 5u and 5w) that were subsequently confirmed to be non-toxic to osteoblasts. Further investigation revealed that compound 5w displayed the most potent osteoanabolic effect, promoting osteoblast differentiation and upregulating mRNAs expression of osteogenic gene. Based on the promising in vitro and in vivo activity, structure-activity relationship (SAR) analysis revealed a furan ring on the dihydropyrimidinone unit and electron-donating groups on the N-phenyl ring of the pyrazole moiety to be crucial for osteogenic activity. Additionally, molecular docking, favorable pharmacokinetic properties and In silico ADME predictions suggest potential oral bioavailability. These findings establish the pyrazole-dihydropyrimidinone scaffold as a promising hit for developing a new class of orally active bone anabolic agents.

Innovative Pyrazole Hybrids: A New Era in Drug Discovery and Synthesis

Heterocyclic compounds that include nitrogen and their derivatives have long been regarded as excellent sources of medicinal substances. Pyrazole is a compound with two nitrogen atoms and an aromatic structure. It has several uses and intricate stereochemistry arranged in a five-membered ring. The knowledge of different pyrazole derivatives and their range of physiological and pharmacological actions has grown significantly in recent years. The scientific community has recently increasingly focused on exploring the chemistry of various pyrazole hybrids due to their enhanced biological activities. This review investigates the chemistry of these diverse pyrazole hybrids, emphasizing their synthesis and their antidiabetic, antibacterial, anticancer, antimicrobial, antioxidant, and anti-inflammatory activities. Articles published from 2014 onward with an emphasis on the last 5 years are included in this review. This review is anticipated to be useful for future investigations and innovative concepts in the pursuit of designs for creating more promising hybrids of pyrazoles.

Review of the recent advances of pyrazole derivatives as selective COX-2 inhibitors for treating inflammation

Pyrazole heterocycle is regarded as an extremely significant agent for the therapy of inflammation. Celecoxib, lonazolac, deracoxib, and phenylbutazone are examples of commercially approved pyrazole drugs with COX-2 inhibitory potential for curing inflammation. There have been recently many reviews for the biological significance of pyrazole derivatives. This review talks about pyrazole derivatives with anti-inflammatory activity and also sheds the light on the recent updates on pyrazole research with an emphasis on some synthetic pathways utilized to construct this privileged scaffold and structure activity relationship that accounts for the anti-inflammatory activity in an attempt to pave the opportunity for medicinal chemists to develop novel anti-inflammatory agents with better COX-2 selectivity.

The Importance of Murine Models in Determining In Vivo Pharmacokinetics, Safety, and Efficacy in Antimalarial Drug Discovery

New chemical entities are constantly being investigated towards antimalarial drug discovery, and they require animal models for toxicity and efficacy testing. Murine models show physiological similarities to humans and are therefore indispensable in the search for novel antimalarial drugs. They provide a preclinical basis (following in vitro assessments of newly identified lead compounds) for further assessment in the drug development pipeline. Specific mouse strains, non-humanized and humanized, have successfully been infected with rodent Plasmodium species and the human Plasmodium species, respectively. Infected mice provide a platform for the assessment of treatment options being sought. In vivo pharmacokinetic evaluations are necessary when determining the fate of potential antimalarials in addition to the efficacy assessment of these chemical entities. This review describes the role of murine models in the drug development pipeline. It also explains some in vivo pharmacokinetic, safety, and efficacy parameters necessary for making appropriate choices of lead compounds in antimalarial drug discovery. Despite the advantages of murine models in antimalarial drug discovery, certain limitations are also highlighted.

Regioselective Pyrazole Synthesis via Base-Mediated [3+2] Cycloaddition of 2-Alkynyl-1,3-Dithianes and Sydnones

We present a novel base-mediated [3+2] cycloaddition for the regioselective synthesis of polysubstituted pyrazoles using 2-alkynyl-1,3-dithianes and sydnones. By exploiting the umpolung and nucleophilic properties of 2-alkynyl-1,3-dithianes, this method achieves efficient pyrazole construction under mild conditions with excellent regioselectivity, broad functional group tolerance, and diverse substrate compatibility. Furthermore, the unique reactivity of the dithianyl group enables facile derivatization and synthesis of highly functionalized pyrazoles.

Development of 1,2,3-triazole hybrids as multi-faced anticancer agents co-targeting EGFR/mTOR pathway and tubulin depolymerization

Novel 1,2,3-triazole hybrids bearing various substituents have been synthesized as potential anticancer agents. Ligand-based approach has been adopted to design these compounds relying on the hybridization of 1,2,3-triazole with α,β-unsaturated carbonyl, 5- and 6-membered heterocyclic scaffolds. All synthesized members were investigated for their cytotoxic potency against nine types comprising 60 panels of human cancerous cells by the US National Cancer Institute: Development Therapeutic Program (US_NCI_DTP). Among the tested members, 4b, 4e, and 4h showed prominent cytotoxic effects (> 80 % growth inhibition: GI) on a wide panel of tested cancer cell lines, mainly melanoma and colorectal cancer redeeming their selection for five dose testing. Presenting low nanomolar GI50 concentrations, two representative potent anticancer compounds 4b and 4e were subjected to cytotoxicity testing on colon normal cell (FHC) to investigate their safety window and they showed less toxicity to normal cells at the concentration required to produce anticancer effect. Furthermore, 4b and 4e were exposed to additional mechanistic studies in colorectal cancer cell HCT-116 suggesting multifaceted mechanisms of action. A study into the effects of cytotoxic chemicals 4b and 4e on cell cycle progression regulation showed triggered the arrest of cell cycles during the G1 and S phases. Moreover, 4b and 4e caused cell death mainly through apoptosis the thing that has been reinforced by the elevated Bax: Bcl2 ratio, as well as concentrations of caspases 3 and 9 within HCT-116. Further, both compounds showed prominent inhibition profiles against tubulin polymerization as well as EGFR catalytic activity reaching down to low-digit micromolar and sub-micromolar concentrations, respectively, as compared to positive reference controls. Compounds' impacts on gene expression of cancer-associated and EGFR-downstream signaling markers including TNFα, IL-6, and mTOR, were explored in HCT-116 highlighted significant downregulations versus the untreated cells. Docking studies demonstrated the specific fit of 4b and 4e into EGFR and the colchicine binding site of tubulin.

Emerging nanotechnology-driven drug delivery solutions for malaria: Addressing drug resistance and improving therapeutic success

Malaria remains the fifth deadliest parasitic infection worldwide, despite significant advancements in technology. A major challenge in combating this disease lies in the growing resistance of malaria parasites to antimalarial drugs and insect vectors to insecticides. The emerging inefficacy of artemisinin-based combination therapies (ACTs) further exacerbates the issue. Additionally, the absence of a highly effective malaria vaccine continues to be a significant obstacle. The complex biology of the malaria parasite and the multifaceted nature of the disease contribute to these challenges. Recent advancements in nanotechnology offer promising solutions in malaria treatment, providing benefits such as improved drug stability, sustained release, and targeted delivery to specific cells. Encapsulation technology, in particular, addresses critical limitations like poor solubility, low bioavailability, and frequent dosing requirements. Thus, this review explores innovative strategies to combat malaria, focusing on nanotechnology-based antimalarial formulations and their evaluation in vitro and in vivo. Moreover, the study highlights the SAR of potent antimalarial compounds, molecular markers linked with drug resistance, ACTs, advocates for eco-friendly approaches, nanotechnology-driven vaccines, and new antimalarial agents with their specific targets.

Study of physiochemical properties of trisubstituted pyrazole derivatives using polar aprotic solvents

Pyrazole derivatives are aromatic heterocyclic compounds endowed with multifaceted applications. In the present study 1,3,4-trisubstituted pyrazoles derivatives have been synthesized for the purpose of studying their physical properties and their characterization was done by FTIR, 1H NMR and 13C NMR spectroscopic technique. The measurement of densities (ρ) and viscosities (η) of solutions of substituted pyrazole derivative in polar aprotic solvent i.e., Dimethyl sulfoxide (DMSO), nitromethane (NM) as well as in their 1:1 binary mixture (DMSO + NM) was done at 310 K over a wide range of solute concentration (5-100) × 10-4 mol dm-3. The experimental results were used to determine the excess molar volumes ( V m E ) . The data of density-viscosity revealed the dipole-dipole interactions occurred between the pyrazole derivative (solute) and the solvent (DMSO, NM). Excess molar studies ( V m E ) revealed that solute-solvent interaction was found to be stronger in case of nitromethane solvent.

Novel frontiers through nitrogen substitution at 6th, 10th and 11th position of artemisinin: Synthetic approaches and antimalarial activity

Malaria pertains to an array of catastrophic illnesses spurred on by the Plasmodium spp. Artemisinin (ART) is currently prescribed in conjunction with another medication as part of therapeutic regimens for acute malaria. These currently prescribed pharmaceuticals have been around for a while, even after lack of required thermos-metabolic stabilities, alongside fresh proclaims about surfacing resistance and neurotoxicity linked with sequential administration of such combination therapies. Over the years, ARTs seem to have gained popularity through the accelerated reduction in parasitaemia, thus dictating use of differentially stable ART derivatives, in combination or alone, to control the proliferation of malaria. The endoperoxide bridge in the ART pharmacophore plays a non-negotiable role in its action against multiple stages in the parasitic life cycle. However, shorter half-lives and limited bioavailability tend to open doors for another class of endoperoxides. Nitrogen substitution at 6th, 10th and 11th positions of ART draws attention as the best replacements through their disparate stabilities and inability to demonstrate in vivo hydrolytic decomposition into DHA. Discussions pertaining such azaartemisinins and aminoartemisinins reported over the past 30 years have been strongly focused upon, on account of their synthetic methodologies and antimalarial efficacies, in order to assign future candidature to the meritorious moiety.

Thiazole - A promising scaffold for antituberculosis agents and structure-activity relationships studies

Research on thiazole derivatives has been a popular topic in medicine and one of the most active fields in heterocyclic chemistry. Pharmacological and industrial researchers have been studying thiazole-containing derivatives in great detail because they have a lot of biological uses. These compounds are one of the best examples of a five-membered heterocyclic compound that has a lot of potential and has had a lot of success in recent decades. Investigating viable hybrid designs utilizing thiazole is critical for the development of new anti-tuberculosis medications. This article offers a thorough overview of the latest advancements in thiazole-containing hybrids, offering potential therapeutic applications as anti-TB drugs. We also discussed the structure-activity correlations (SAR) of the powerful thiazole moiety and its several functional groups, along with a few potential molecular targets.

Diastereomeric pure pyrazolyl-indolyl dihydrofurans: Unveiling isomeric selectivity in antibacterial action via in vitro and in silico insights

Developing pure diastereoisomeric molecular hybrids for the selective inhibition of bacterial growth opened new avenues for combating the ever-increasing microbial resistance. Considering this, a series of diastereoisomeric pure pyrazolyl-dihydrofurans (7a-7y) were synthesized and characterized using NMR, LCMS, and X-ray crystallography. DFT based method was used to explore the configurational stability of cis over trans isomeric form. Considering 7a and 8a as representative isomeric forms with same structural framework, the difference in their bio-efficacy against bacterial and fungal strains was assessed using serial dilution method. The relatively high inhibition of bacterial growth by the cis isomeric form (7a) (MIC = 1.562 µg/mL), amoxicillin (MIC = 3.125 µg/mL) inspired us to broaden the substrate scope for synthesizing a series of pure diastereoisomeric cis forms as selective anti-bacterial agents. However, both the isomers displayed antifungal activity less than the standard drug (Fluconazole) employed in the study. All the reactions proceeded smoothly and yielded a diverse array of dihydrofuran derivatives. The developed synthetics were found to be non-cytotoxic against mouse fibroblast cells and didn't affect the seed germination of Brassica nigra seeds when treated at 1 mg/mL concentration. The experimentally determined in vitro results were further validated using in silico molecular docking and dynamics studies.

Design, Synthesis, Molecular Docking, and ADME-Tox Investigations of Imidazo[1,2-a]Pyrimidines Derivatives as Antimicrobial Agents

A convenient and effective synthesis of imidazo[1,2-a]pyrimidine derivatives has been developed under microwave irradiations using Al2O3 as a catalyst in solvent-free conditions. The functionalized imidazo[1,2-a]pyrimidine derivatives are useful in biochemistry and medical science. In our investigation, the antimicrobial activity of the synthesized compounds was evaluated against 13 microorganisms, including 6 Gram-positive bacteria, 4 Gram-negative bacteria, and 3 pathogenic fungi. Bioactivity tests revealed that the majority of the compounds exhibited good antimicrobial activity. Finally, molecular docking simulations and ADME-T predictions were performed, showing that the most active compounds have good binding modes with microbial targets and promising pharmacokinetic safety profiles.

Development and assessment of novel pyrazole-thiadiazol hybrid derivatives as VEGFR-2 inhibitors: design, synthesis, anticancer activity evaluation, molecular docking, and molecular dynamics simulation

Cancer remains a significant health challenge globally, requiring the development of targeted chemotherapeutics capable of specifically inhibiting cancer cell growth. Angiogenesis is one of the key features of tumor growth and metastasis and is, therefore, an important target for the treatment of many tumors. The vascular endothelial growth factor (VEGF) signaling pathway has proven to be a promising lead in anticancer therapy due to the central role it plays in tumor angiogenesis. Vascular endothelial growth factor receptor-2 (VEGFR-2) is a key mediator in the signaling pathway regulating angiogenesis. Targeting VEGFR-2 may disrupt angiogenesis, leading to a reduction in tumor blood supply and tumor progression. The design, synthesis, and assessment of novel VEGFR-2 inhibitor derivatives are the focus of this study, with particular emphasis on incorporating the pyrazole-thiadiazol pharmacophore into the molecular structure. Taking advantage of the pharmacophoric properties of pyrazole and 1,3,4-thiadiazol, compounds with different substituents in the main structure were designed and synthesized. The compounds were also evaluated for antiproliferative activity against cancer cell lines. Compound 4e demonstrated the highest activity among all compounds, with an IC50 of 9.673 ± 0.399 μM against HT-29 cells and 23.081 ± 0.400 μM against NIH3T3 cells. To further support the inhibitory activity of compound 4e, an in silico study was performed. Compound 4e demonstrated strong binding to the active site of VEGFR-2 in molecular docking studies, forming hydrogen bonds with key amino acid residues. The stability of the compound in the enzyme's active site was demonstrated through molecular dynamics simulations.

Catalytic enantioselective synthesis of 2-pyrazolines via one-pot condensation/6π-electrocyclization: 3,5-bis(pentafluorosulfanyl)-phenylthioureas as powerful hydrogen bond donors

A new conjugate-base-stabilized carboxylic acid (CBSCA) containing a 3,5-bis(pentafluorosulfanyl)phenylthiourea functionality catalyses challenging one-pot condensations/6π-electrocyclizations of hydrazines and α,β-unsaturated ketones under mild conditions. Structurally diverse N-aryl 2-pyrazolines are obtained in good yields and enantioselectivities. The superior performance of 3,5-bis(SF5)phenylthioureas over the widely used 3,5-bis(CF3)phenylthioureas is further demonstrated in the Michael addition of dimethyl malonate to nitrostyrene, using a new Takemoto-type catalyst.

Exploring antimalarial potential: Conjugating organometallic moieties with organic fragments for enhanced efficacy

In the search for novel ligands with efficacy against various diseases, particularly parasitic diseases, molecular hybridization of organometallic units into biologically active scaffolds has been hailed as an appealing strategy in medicinal chemistry. The conjugation to organometallic fragments can be achieved by an appropriate linker or by directly coordinating the existing drugs to a metal. The success of Ferroquine (FQ, SR97193), an effective chloroquine-ferrocene conjugate currently undergoing the patient-exploratory phase as a combination therapy with the novel triaminopyrimidine ZY-19489 for malaria, has sparked intense interest in organometallic compound drug discovery. We present the evolution of organometallic antimalarial agents over the last decade, focusing on the parent moiety's class and the type of organometallics involved. Four main organometallic antimalarial compounds have been chosen based on conjugated organic moieties: existing antimalarial drugs, other clinical drugs, hybrid drugs, and promising scaffolds of thiosemicarbazones, benzimidazoles, and chalcones, in particular. The presented insights contribute to the ongoing discourse on organometallic compound drug development for malaria diseases.

Mothana R, M. Noman O, Eto B, Chigr F, Chigr M. Synthesis and In Silico Analysis of New Polyheterocyclic Molecules Derived from [1,4]-Benzoxazin-3-one and Their Inhibitory Effect against Pancreatic α-Amylase and Intestinal α-Glucosidase

This study focuses on synthesizing a new series of isoxazolinyl-1,2,3-triazolyl-[1,4]-benzoxazin-3-one derivatives 5a-5o. The synthesis method involves a double 1,3-dipolar cycloaddition reaction following a "click chemistry" approach, starting from the respective [1,4]-benzoxazin-3-ones. Additionally, the study aims to evaluate the antidiabetic potential of these newly synthesized compounds through in silico methods. This synthesis approach allows for the combination of three heterocyclic components: [1,4]-benzoxazin-3-one, 1,2,3-triazole, and isoxazoline, known for their diverse biological activities. The synthesis procedure involved a two-step process. Firstly, a 1,3-dipolar cycloaddition reaction was performed involving the propargylic moiety linked to the [1,4]-benzoxazin-3-one and the allylic azide. Secondly, a second cycloaddition reaction was conducted using the product from the first step, containing the allylic part and an oxime. The synthesized compounds were thoroughly characterized using spectroscopic methods, including 1H NMR, 13C NMR, DEPT-135, and IR. This molecular docking method revealed a promising antidiabetic potential of the synthesized compounds, particularly against two key diabetes-related enzymes: pancreatic α-amylase, with the two synthetic molecules 5a and 5o showing the highest affinity values of 9.2 and 9.1 kcal/mol, respectively, and intestinal α-glucosidase, with the two synthetic molecules 5n and 5e showing the highest affinity values of -9.9 and -9.6 kcal/mol, respectively. Indeed, the synthesized compounds have shown significant potential as antidiabetic agents, as indicated by molecular docking studies against the enzymes α-amylase and α-glucosidase. Additionally, ADME analyses have revealed that all the synthetic compounds examined in our study demonstrate high intestinal absorption, meet Lipinski's criteria, and fall within the required range for oral bioavailability, indicating their potential suitability for oral drug development.

Novel Pyrazole-4-Carboxamide Derivatives Containing Oxime Ether Group as Potential SDHIs to Control Rhizoctonia solani

In the search for novel succinate dehydrogenase inhibitor (SDHI) fungicides to control Rhizoctonia solani, thirty-five novel pyrazole-4-carboxamides bearing either an oxime ether or an oxime ester group were designed and prepared based on the strategy of molecular hybridization, and their antifungal activities against five plant pathogenic fungi were also investigated. The results indicated that the majority of the compounds containing oxime ether demonstrated outstanding in vitro antifungal activity against R. solani, and some compounds also displayed pronounced antifungal activities against Sclerotinia sclerotiorum and Botrytis cinerea. Particularly, compound 5e exhibited the most promising antifungal activity against R. solani with an EC50 value of 0.039 μg/mL, which was about 20-fold better than that of boscalid (EC50 = 0.799 μg/mL) and 4-fold more potent than fluxapyroxad (EC50 = 0.131 μg/mL). Moreover, the results of the detached leaf assay showed that compound 5e could suppress the growth of R. solani in rice leaves with significant protective efficacies (86.8%) at 100 μg/mL, superior to boscalid (68.1%) and fluxapyroxad (80.6%), indicating promising application prospects. In addition, the succinate dehydrogenase (SDH) enzymatic inhibition assay revealed that compound 5e generated remarkable SDH inhibition (IC50 = 2.04 μM), which was obviously more potent than those of boscalid (IC50 = 7.92 μM) and fluxapyroxad (IC50 = 6.15 μM). Furthermore, SEM analysis showed that compound 5e caused a remarkable disruption to the characteristic structure and morphology of R. solani hyphae, resulting in significant damage. The molecular docking analysis demonstrated that compound 5e could fit into the identical binding pocket of SDH through hydrogen bond interactions as well as fluxapyroxad, indicating that they had a similar antifungal mechanism. The density functional theory and electrostatic potential calculations provided useful information regarding electron distribution and electron transfer, which contributed to understanding the structural features and antifungal mechanism of the lead compound. These findings suggested that compound 5e could be a promising candidate for SDHI fungicides to control R. solani, warranting further investigation.

Structure-Activity Relationship Studies on Highly Functionalized Pyrazole Hydrazones and Amides as Antiproliferative and Antioxidant Agents

Aminopyrazoles represent interesting structures in medicinal chemistry, and several derivatives showed biological activity in different therapeutic areas. Previously reported 5-aminopyrazolyl acylhydrazones and amides showed relevant antioxidant and anti-inflammatory activities. To further extend the structure-activity relationships in this class of derivatives, a novel series of pyrazolyl acylhydrazones and amides was designed and prepared through a divergent approach. The novel compounds shared the phenylamino pyrazole nucleus that was differently decorated at positions 1, 3, and 4. The antiproliferative, antiaggregating, and antioxidant properties of the obtained derivatives 10-22 were evaluated in in vitro assays. Derivative 11a showed relevant antitumor properties against selected tumor cell lines (namely, HeLa, MCF7, SKOV3, and SKMEL28) with micromolar IC50 values. In the platelet assay, selected pyrazoles showed higher antioxidant and ROS formation inhibition activity than the reference drugs acetylsalicylic acid and N-acetylcysteine. Furthermore, in vitro radical scavenging screening confirmed the good antioxidant properties of acylhydrazone molecules. Overall, the collected data allowed us to extend the structure-activity relationships of the previously reported compounds and confirmed the pharmaceutical attractiveness of this class of aminopyrazole derivatives.

Discovery of Pyrano[2,3-c]pyrazole Derivatives as Novel Potential Human Coronavirus Inhibitors: Design, Synthesis, In Silico, In Vitro, and ADME Studies

The SARS-CoV-2 pandemic at the end of 2019 had major worldwide health and economic consequences. Until effective vaccination approaches were created, the healthcare sectors endured a shortage of operative treatments that might prevent the infection's spread. As a result, academia and the pharmaceutical industry prioritized the development of SARS-CoV2 antiviral medication. Pyranopyrazoles have been shown to play a prominent function in pharmaceutical chemistry and drug sighting because of their significant bioactive properties. We provide herein a novel sequence of pyranopyrazoles and their annulated systems whose antiviral efficacy and cytotoxicity were explored versus human coronavirus 229E (HCoV-229E) Vero-E6 cell lines as a model for the Coronaviridae family. Fifteen synthetic congeners pointed out miscellaneous antiviral efficacies against HCoV-229E with variable inhibition degrees. Compound 18 showed a high selectivity index (SI = 12.6) that established spectacular inhibitory capacity against human coronavirus 229E. Compounds 6, 7, and 14 exposed moderate efficacies. Compounds 6, 7, 14, and 18 exhibited substantial antiviral action through the replication phase with reduction percentages extending from 53.6%, 60.7%, and 55% to 82.2%, correspondingly. Likewise, when assessed to the positive control tipranavir (88.6%), the inhibitory efficiency of compounds 6, 7, 14, and 18 versus the SARS-CoV2 Mpro provided high percentages of 80.4%, 73.1%, 81.4% and up to 84.5%, respectively. In silico studies were performed to investigate further the biological activity and the target compounds' physical and chemical features, including molecular dynamic (MD) simulations, protein-ligand docking, ADME studies, and density functional theory (DFT) calculations. These inquiries demonstrated that this series of metabolically stable pyranopyrazoles and their annulated systems are effective human coronavirus inhibitors that inhibit the viral Mpro protein and may have emerged as a novel COVID-19 curative option.

Recent advances in the synthesis and antimalarial activity of 1,2,4-trioxanes

The increasing resistance of various malarial parasite strains to drugs has made the production of a new, rapid-acting, and efficient antimalarial drug more necessary, as the demand for such drugs is growing rapidly. As a major global health concern, various methods have been implemented to address the problem of drug resistance, including the hybrid drug concept, combination therapy, the development of analogues of existing medicines, and the use of drug resistance reversal agents. Artemisinin and its derivatives are currently used against multidrug- resistant P. falciparum species. However, due to its natural origin, its use has been limited by its scarcity in natural resources. As a result, finding a substitute becomes more crucial, and the peroxide group in artemisinin, responsible for the drugs biological action in the form of 1,2,4-trioxane, may hold the key to resolving this issue. The literature suggests that 1,2,4-trioxanes have the potential to become an alternative to current malaria drugs, as highlighted in this review. This is why 1,2,4-trioxanes and their derivatives have been synthesized on a large scale worldwide, as they have shown promising antimalarial activity in vivo and in vitro against Plasmodium species. Consequently, the search for a more convenient, environment friendly, sustainable, efficient, and effective synthetic pathway for the synthesis of 1,2,4-trioxanes continues. The aim of this work is to provide a comprehensive analysis of the synthesis and mechanism of action of 1,2,4-trioxanes. This systematic review highlights the most recent summaries of derivatives of 1,2,4-trioxane compounds and dimers with potential antimalarial activity from January 1988 to 2023.

Exploring the antimalarial and antioxidant efficacy of transition metal(II) chelates of thiosemicarbazone ligands: spectral investigations, molecular docking, DFT, MESP and ADMET

Malaria, a relentless and ancient adversary, continues to cast its shadow over vast swathes of the globe, afflicting millions of people and have a heavy toll on human health and well-being. Despite substantial progress in the fight against this parasitic disease in recent decades, malaria still persists as a substantial global health concern, especially in some specific region which have limited resources and vulnerable populations. Thus, to ascertain an combating agent for malaria and its associated dysfunction, 4-(4-ethylphenyl)-3-thiosemicarbazide and benzaldehydes based two new thiosemicarbazone ligands (1-2) and their cobalt(II), nickel(II), copper(II), zinc(II) metal complexes (3-10) were synthesized in the present research work. The synthesized compounds were comprehensive characterized through spectral and physical investigations, demonstrating octahedral stereochemistry of the complexes. Further, the antimalarial and antioxidant potential of the compounds (1-10) were analyzed by micro assay and DPPH assay protocols, respectively, to examine the therapeutic aspect of the compounds. The performed biological evaluations revealed that the complexes are more efficient in controlling infectious ailment in comparison of ligands. The complexes (5), (6), (10) shows significant efficiency for malarial and oxidant dysfunctions whereas Zn(II) complex (6) exhibit highest potency with 1.02 ± 0.07 and 2.28 ± 0.05 µM IC50 value. Furthermore, to support the highest antimalarial potency of the (3-6) complexes and their associated ligand (1), the computational studies like molecular docking, DFT, MESP and ADMET analysis were executed which were supported the biological efficacy of the complex (6) by providing numerous parameters like binding interaction electronegativity, electrophilicity, HOMO value and electron density.

Recent developments of P-glycoprotein inhibitors and its structure-activity relationship (SAR) studies

P-glycoprotein (P-gp) over-expression is a key factor in multi-drug resistance (MDR), which is a major factor in the failure of cancer treatment. P-gp inhibitors have been demonstrated to have powerful pharmacological properties and may be used as a therapeutic approach to overcome the MDR in cancer cells. Combining clinical investigations with biochemical and computational research may potentially lead to a clearer understanding of the pharmacological properties and the mechanisms of action of these P-gp inhibitors. The task of turning these discoveries into effective therapeutic candidates for a variety of malignancies, including resistant and metastatic kinds, falls on medicinal chemists. A variety of P-gp inhibitors with great potency, high selectivity, and minimal toxicity have been identified in recent years. The latest advances in drug design, characterization, structure-activity relationship (SAR) research, and modes of action of newly synthesized, powerful small molecules P-gp inhibitors over the previous ten years are highlighted in this review. P-gp transporter over-expression has been linked to MDR, therefore the development of P-gp inhibitors will expand our understanding of the processes and functions of P-gp-mediated drug efflux, which will be helpful for drug discovery and clinical cancer therapies.

In silico and in vitro prediction of new synthesized N-heterocyclic compounds as anti-SARS-CoV-2

Computer-aided drug design has been employed to get the medicinal effects against Corona virus from different pyridine derivatives after synthesizing the new compounds. Additionally, various computational studies are also employed between the newly prepared pyridine derivatives and three controls against three proteins (6Y2E, 6M71 and 6M3M). Different methods were employed to synthesize new pyridine derivatives according to the literature using different reaction mediums. MTT was performed for cytotoxicity study and IC50 for inhibitory concentration. Additionally, in-silico studies including DFT, molecular docking, molecular dynamics, MMPBSA, ADME, pharmacokinetics and Lipinski rules were evaluated. The chemical structures of all new compounds were elucidated based on spectroscopic investigation. A molecular docking study demonstrated that compounds 5, 11, and 12 have the best binders of the SARS-CoV-2 main protease enzyme, with energy scores of - 7.5 kcal/mol, - 7.2 kcal/mol, and - 7.9 kcal/mol, respectively. The net binding energy values of the 11-Mpro, 12-Mpro, and 5-Mpro complexes revealed their highly stable nature in terms of both intermolecular interactions and docked conformation across the simulation time. ADME properties, besides the pharmacokinetics and Lipinski rules, showed that all seven newly synthesized compounds follow Lipinski rules with high GI absorption. The In Vitro antiviral study against SARS-CoV-2 using MTT methods confirms that compound 5 has more potential and is safer than other tested compounds. The study shows that the newly synthesized pyridine derivatives have medicinal properties against SARS-CoV-2 without violating Lipinski rules. Compounds 5, 11, and 12, particularly compound 5, may serve as promising potential candidate for COVID-19.

Design, Synthesis and Evaluation of Antifungal Activity of Pyrazoleacetamide Derivatives

BACKGROUND

Fungal infections have posed a big challenge in the management of their treatment. Due to the resistance and toxicity of existing drug molecules in the light of pandemic infections, like COVID-19, there is an urgent need to find newer derivatives of active molecules, which can be effective in fungal infections.

OBJECTIVE

In the present study, we aimed to design pyrazole derivatives using molecular modeling studies against target 1EA1 and synthesize 10 molecules of pyrazole derivatives using a multi-step synthesis approach.

METHODS

Designed pyrazole derivatives were synthesized by conventional organic methods. The newly synthesized pyrazole molecules were characterized by using FT-IR, 1HNMR, 13CNMR, and LC-MS techniques. Molecular docking studies were also performed. The antifungal activity of newly synthesized compounds was assessed in vitro against Candida albicans and Aspergillus niger using the well plate method.

RESULTS

Two of the compounds, OK-7 and OK-8, have been found to show significant docking interaction with target protein 1EA1. These two compounds have also been found to show significant anti-fungal activity against Candida albicans and Aspergillus nigra when compared to the standard fluconazole. The Minimum Inhibitory Concentration (MIC) value of these two compounds has been found to be 50 μg/ml.

CONCLUSION

Pyrazole derivatives with -CH3, CH3O-, and -CN groups have been found to be active against tested fungi and can be further explored for their potential as promising anti-fungal agents for applications in the field of medicinal chemistry.

In silico prediction and in vitro assessment of novel heterocyclics with antimalarial activity

The development of new antimalarials is paramount to keep the goals on reduction of malaria cases in endemic regions. The search for quality hits has been challenging as many inhibitory molecules may not progress to the next development stage. The aim of this work was to screen an in-house library of heterocyclic compounds (HCUV) for antimalarial activity combining computational predictions and phenotypic techniques to find quality hits. The physicochemical determinants, pharmacokinetic properties (ADME), and drug-likeness of HCUV were evaluated in silico, and compounds were selected for structure-based virtual screening and in vitro analysis. Seven Plasmodium target proteins were selected from the DrugBank Database, and ligands and receptors were processed using UCSF Chimera and Open Babel before being subjected to docking using Autodock Vina and Autodock 4. Growth inhibition of P. falciparum (3D7) cultures was tested by SYBR Green assays, and toxicity was assessed using hemolytic activity tests and the Galleria mellonella in vivo model. From a total of 792 compounds, 341 with good ADME properties, drug-likeness, and no interference structures were subjected to in vitro analysis. Eight compounds showed IC50 ranging from 0.175 to 0.990 µM, and active compounds included pyridyl-diaminopyrimido-diazepines, pyridyl-N-acetyl- and pyridyl-N-phenyl-pyrazoline derivatives. The most potent compound (UV802, IC50 0.178 µM) showed no toxicophoric and was predicted to interact with P. falciparum 1-cysperoxidredoxin (PfPrx1). For the remaining 7 hits (IC50 < 1 μM), 3 showed in silico binding to PfPrx1, one was predicted to bind the haloacid dehalogenase-like hydrolase and plasmepsin II, and one interacted with the plasmodial heat shock protein 90.

Triazole hybrid compounds: A new frontier in malaria treatment

Reviewing the advancements in malaria treatment, the emergence of triazole hybrid compounds stands out as a groundbreaking development. Combining the advantages of triazole and other moieties, these hybrid compounds offer a new frontier in the battle against malaria. Their potential as effective antimalarial agents has captured the attention of researchers and holds promise for overcoming the challenges posed by drug-resistant malaria strains. We focused on their broad spectrum of antimalarial activity of diverse hybridized 1,2,3-triazoles and 1,2,4-triazoles, structure-activity relationship (SAR), drug-likeness, bioavailability and pharmacokinetic properties reported since 2018 targeting multiple stages of the Plasmodium life cycle. This versatility makes them highly effective against both drug-sensitive and drug-resistant strains of P. falciparum, making them invaluable tools in regions where resistance is prevalent. The synergistic effects of combining the triazole moiety with other pharmacophores have resulted in even greater antimalarial potency. This approach has the potential to circumvent existing resistance mechanisms and provide a more sustainable solution to malaria treatment. While triazole hybrid compounds show great promise, further research and clinical trials are warranted to fully evaluate their safety, efficacy and long-term effects. As research progresses, these compounds can potentially revolutionize the field and contribute to global efforts to eradicate malaria, ultimately saving countless lives worldwide.

Pyrazole: an emerging privileged scaffold in drug discovery

Pyrazole or 1H-pyrazole, a five-membered 1,2-diazole, is found in several approved drugs and some bioactive natural products. A myriad number of derivatives of this small molecule have been reported in clinical and preclinical studies for the potential treatment of several diseases. The number of drugs containing a pyrazole nucleus has increased significantly in the last 10 years. Some of the best-selling drugs in this class are ibrutinib, ruxolitinib, axitinib, niraparib and baricitinib, and are used to treat different types of cancers; lenacapavir to treat HIV; riociguat to treat pulmonary hypertension; and sildenafil to treat erectile dysfunction. Several aniline-derived pyrazole compounds have been reported as potent antibacterial agents with selective activity against methicillin-resistant Staphylococcus aureus and vancomycin-resistant enterococci. Here, we discuss the pyrazole-derived drugs reported up to September 2023.

Green synthesis of highly functionalized heterocyclic bearing pyrazole moiety for cancer-targeted chemo/radioisotope therapy

New derivatives of heterocyclic bearing pyrazole moiety were synthesized (eight new compounds from 2 to 9) via green synthesis methods (microwave-assisted and grinding techniques). 4,6-Diamino-1,3-diphenyl-1H-pyrazolo[3,4-b]pyridine-5-carbonitrile (2) shows high anti-cancer activity against both HepG2 and HCT-116 with IC50 of 9.2 ± 2.8 and 7.7 ± 1.8 µM, respectively, which referenced to 5-Fu which is showing activity of 7.86 ± 0.5 and 5.35 ± 0.3 against both HepG2 and HCT-116, respectively. The cytotoxic activity against HCT-116 and HepG2 was slightly decreased and slightly increased, respectively, by a different pyrazole moiety (compound 5). Pharmacokinetics of compound 2 was carried out using the radioiodination technique in tumour-bearing Albino mice which shows good uptake at the tumour site. The biodistribution showed high accumulation in tumour tissues with a ratio of 13.7% ID/g organ after one hour in comparison with 2.97% ID/g organ at normal muscle at the same time point. As I-131 has maximum beta and gamma energies of 606.3 and 364.5 keV, respectively, therefore the newly synthesized compound 2 may be used for chemotherapy and TRT.

Development and Antibacterial Properties of 4-[4-(Anilinomethyl)-3-phenylpyrazol-1-yl]benzoic Acid Derivatives as Fatty Acid Biosynthesis Inhibitors

A number of novel pyrazole derivatives have been synthesized, and several of these compounds are potent antibacterial agents with minimum inhibitory concentrations as low as 0.5 μg/mL. Human cell lines were tolerant to these lead compounds, and they showed negligible hemolytic effects at high concentrations. These bactericidal compounds are very effective against bacterial growth in both planktonic and biofilm contexts. Various techniques were applied to show the inhibition of biofilm growth and eradication of preformed biofilms by lead compounds. Potent compounds are more effective against persisters than positive controls. In vivo studies revealed that lead compounds are effective in rescuing C. elegans from bacterial infections. Several methods were applied to determine the mode of action including membrane permeability assay and SEM micrograph studies. Furthermore, CRISPRi studies led to the determination of these compounds as fatty acid biosynthesis (FAB) inhibitors.

Double Bond Geometric Isomers of Pentaketide Ansamycins from Streptomyces sp. S008

Six new pentaketide ansamycins, namely, shengliangmycins A-F (1-6, respectively), were obtained from the fermentation products of Streptomyces sp. S008OEslmR2 that was derived by constitutive expression of LAL regulator gene slmR2. The structures of 1-6 were determined through comprehensive spectroscopic analysis and single-crystal X-ray diffraction. Compound 1 has a cis-C6═C7 bond, which is different from that of compounds 2-5. Compounds 3-6 feature a morpholinone structural moiety, whereas 5 is characterized by a pyrazoline ring, which is rare in natural products.

Current scenario of pyrazole hybrids with in vivo therapeutic potential against cancers

Chemotherapeutics occupy a pivotal role in the medication of different types of cancers, but the prevalence and mortality rates of cancer remain high. The drug resistance and low specificity of current available chemotherapeutics are the main barriers for the effective cancer chemotherapy, evoking an immediate need for the development of novel anticancer agents. Pyrazole is a highly versatile five-membered heterocycle with two adjacent nitrogen atoms and possesses remarkable therapeutic effects and robust pharmacological potency. The pyrazole derivatives especially pyrazole hybrids have demonstrated potent in vitro and in vivo efficacies against cancers through multiple mechanisms, inclusive of apoptosis induction, autophagy regulation, and cell cycle disruption. Moreover, several pyrazole hybrids such as crizotanib (pyrazole-pyridine hybrid), erdafitinib (pyrazole-quinoxaline hybrid) and ruxolitinib (pyrazole-pyrrolo [2,3-d]pyrimidine hybrid) have already been approved for the cancer therapy, revealing that pyrazole hybrids are useful scaffolds to develop novel anticancer agents. The purpose of this review is to summarize the current scenario of pyrazole hybrids with potential in vivo anticancer efficacy along with mechanisms of action, toxicity, and pharmacokinetics, covering papers published in recent 5 years (2018-present), to facilitate further rational exploitation of more effective candidates.