Pyrazole-based analogs as potential antibacterial agents against methicillin-resistance staphylococcus aureus (MRSA) and its SAR elucidation

A phytotherapeutic approach to hinder the resistance against clindamycin by MRSA: in vitro and in silico studies

AIMS

This study investigates the potential effects of essential oils (EOs) in enhancing the efficacy of clindamycin against Methicillin-resistant Staphylococcus aureus (MRSA) using in vitro and computer simulations. The research seeks to identify essential oils that exhibit synergistic activity with clindamycin and determine their potential key active components.

MATERIALS AND METHODS

Essential oils commonly used in traditional medicine were tested for their antimicrobial activity against MRSA. The minimum inhibitory concentration (MIC) was determined using in vitro microdilution assays. A synergistic test with clindamycin was performed, and molecular docking studies evaluated the interaction between a key compound (trans-cinnamaldehyde) and MRSA protein.

RESULTS

EOs from Cinnamomum verum, Rosmarinus officinalis, Salvia officinalis, and Thymus vulgaris demonstrated significant inhibitory and synergistic activities against MRSA, standard strain, and human clinical isolates. Gas Chromatography/Mass Spectroscopy identified trans-cinnamaldehyde, eucalyptol, and thymol as prominent antibacterial compounds. Molecular docking studies confirmed trans-cinnamaldehyde's strong binding to MRSA's AgrA protein, elucidating its enhanced efficacy.

CONCLUSION

The study underscores the potential of plant-based therapies to augment the effectiveness of conventional antibiotics like clindamycin in combating MRSA and addressing antibiotic resistance by integrating traditional plant remedies with modern medical approaches.

Design and synthesis of benzothiazole aryl urea derivatives as potent anti-staphylococcal agents targeting autolysin-mediated peptidoglycan hydrolases

Novel benzothiazole aryl ureas were designed and synthesized as anti-MRSA agents targeting peptidoglycan (PG) hydrolases (autolysins). Structural simplification of prior benzothiazole-urea hybrids yielded compounds 4a, 7a and 11a bearing p-CF3 on phenyl ring demonstrating narrow-spectrum activity against Gram-positive bacteria including clinical methicillin-resistant S. aureus (MRSA). The primary autolysin in S. aureus, AtlA, mediates peptidoglycan hydrolase activity critical for bacterial growth, division, and cell wall remodeling. Mechanistic studies revealed that 4a down-regulated autolysin-related genes RNAIII and walR, disrupting peptidoglycan homeostasis. Knockout of atlA (a key autolysin gene) impaired 4a's efficacy, confirming autolysins as critical targets. Docking indicated that 4a binds to AtlA via hydrogen bonds, Pi-Pi, and hydrophobic interactions. In vivo, 4a significantly reduced bacterial load in a murine abdominal infection model, outperforming vancomycin at 10 mg/kg with lower cytotoxicity. Additionally, 4a disrupted MRSA biofilms, suppressed hemolytic toxin production, and alleviated inflammation in infected mice. These findings underscore AtlA as a promising therapeutic target and highlight benzothiazole phenyl urea as a scaffold for developing innovative anti-staphylococcal agents.

Copper(II) tetrapyrazole-based complex as a new peroxidase-mimetic compound

A copper(II) tetrapyrazole-based complex of the composition of [Cu(tpyr)(H2O)(ONO2)]NO3 (1), where tpyr represents a tetradentate N-donor ligand formed by the condensation of 1H-pyrazole-5-carbaldehyde in NaOH/MeOH medium, has been prepared and characterized by elemental analysis, infrared spectroscopy, ultraviolet-visible spectroscopy, mass spectrometry, electron paramagnetic resonance and single-crystal X-ray diffraction. Spectrophotometric measurements demonstrated a remarkable peroxidase activity of the complex, which utilized hydrogen peroxide for the oxidation of phenolic compounds such as guaiacol or 3,5-dichloro-2-hydroxybenzene sulfonic acid. The optimum conditions for this reaction were found at pH 8 in ammonium bicarbonate buffer, although the activity was low but still detectable at pH 5-6 in ammonium acetate. As a peroxidase mimic, the complex exhibited enzyme-like Michaelis-Menten kinetics, showing a hyperbolic dependence of the reaction rate on hydrogen peroxide concentration. The determined Km and kcat values were 651 μmol·l-1 and 6.7 × 10-4 s-1, respectively, compared to 41 μmol·l-1 and 73 s-1 for horseradish peroxidase. EPR spectroscopy of the reaction mixture revealed no change in the copper (II) oxidation state during catalysis, suggesting that the oxidation of guaiacol may occur simultaneously with the reduction of hydrogen peroxide to water at the copper centre.

Design, Synthesis and Alpha-glucosidase Inhibitory Effect of Pyrazole-1,2,3-Triazole Hybrids

A novel pyrazole-1,2,3-triazole hybrids were developed and evaluated for its glucosidase inhibitory effects. The targeted 1,2,3-triazole hybrids were obtained from the copper-catalyzed reaction between azide and pyrazole alkyne in dichloromethane at room temperature. Compounds with 4-nitro and 4-chloro groups, respectively, proved the most significant, promising α-glucosidase inhibition activity with IC50 values of 3.35 and 6.58 µM, related to the cited inhibitor, acarbose (IC50 = 3.86 µM). Further, molecular docking studies of the most active compounds were carried out, and the results demonstrated considerable binding modes in the active site of the human lysosomal acid-alpha-glucosidase enzyme. In addition, the density functional theory was carried out to predict the electronic properties of active ligands. Structure-activity relationship analysis implied that the electron-leaving functions at the para position account for the variable enzyme inhibition. Therefore, developing novel therapeutic agents may assist as structural models in exploring diabetes mellitus.

Recent advances in zirconium-based catalysis and its applications in organic synthesis: a review

In recent years, transition metal-catalysed organic synthesis has received great importance. Zirconium, a second-row transition metal, has gained prominence owing to its luster and abundance, but it is more expensive than other transition metals because it is difficult to refine and process. In particular, active zirconia-based catalysts have fascinated researchers owing to their low toxicity, affordability, flexibility and excellent dispersion. This review focuses on the latest zirconium catalysts used in the manufacturing of medicinal compounds, bioactive molecules and pertinent synthesis mechanisms reported since 2020. In this review, the synthesis of various heterocycles such as imidazoles, pyrazole, pyrimidinones, quinolines, quinazolinones, pyridines, pyrroles, benzopyrans, substituted amides and triazolidine-based bioactive molecules is discussed in detail. Future research in this area is based on further understanding the scope of zirconium catalysed sustainable and approachable synthesis of biologically active compounds.

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.

Photothermally Enhanced Cascaded Nanozyme-Functionalized Black Phosphorus Nanosheets for Targeted Treatment of Infected Diabetic Wounds

Due to the limitations of H2O2 under physiological conditions and defective activity, nanozyme-catalyzed therapy for infected diabetic wound healing is still a huge challenge. Here, this work designs a novel multifunctional hybrid glucose oxidase (GOx)-CeO2@black phosphorus (BP)/Apt nanosheet that features GOx and CeO2 dual enzyme loading with photothermal enhancement effect and targeting ability for the treatment of infected wounds in type II diabetic mice. Combined with the photothermal properties of the BP nanosheets, the cascade nanozyme effect of GOx and CeO2 is extremely enhanced. The synergistic effect of peroxidase activity and photothermal therapy with targeting aptamer allows for overcoming the catalytic defects of nanozyme and significantly improving in vitro bacterial inhibition rate with 99.9% and 97.8% for Staphylococcus aureus and Escherichia coli, respectively, as well as enhancing in vivo antibacterial performance with the lowest wound remained (0.05%), reduction of infiltration inflammatory cells, and excellent biocompatibility. Overall, this work builds a nanodelivery system with a powerful therapeutic approach, incorporating self-supplying H2O2 synergistic photothermal and real-time wound monitoring effect, which holds profound potential as a clinical treatment for infected diabetic wounds.

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.

The anti-Acinetobacter baumannii therapeutic potential of azole hybrids: A mini-review

Acinetobacter baumannii is one of the major causes of severe hospital- and community-acquired infections, posing a significant threat to human lives. A. baumannii has already generated resistance to almost all of the currently available antibiotics, but no new class of antibacterials have been launched for the treatment of infections caused by A. baumannii in the last half century, creating an urgent need to develop novel antibacterials. Azoles as a broad class of five-membered nitrogen-containing aromatic heterocycles are privileged pharmacophores widely found in pharmaceuticals. Azoles could target on diverse enzymes, proteins, and receptors in A. baumannii via various noncovalent interactions. Particularly, azole hybrids have potential advantages in increasing therapeutic efficacy and circumventing drug resistance, representing useful scaffolds for the discovery of novel anti-A. baumannii agents. This review outlines the current scenario of the antibacterial therapeutic potential of azole hybrids against A. baumannii, developed from 2020 onwards, aiming to provide potential candidates for further preclinical/clinical evaluations and facilitate the rational design of more effective candidates.

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.

Antibacterial and antifungal pyrazoles based on different construction strategies

The growing prevalence of microbial infections, and antimicrobial resistance (AMR) stemming from the overuse and misuse of antibiotics, call for novel therapeutic agents, particularly ones targeting resistant microbial strains. Scientists are striving to develop innovative agents to tackle the rising microbial infections and abate the risk of AMR. Pyrazole, a five-membered heterocyclic compound belonging to the azole family, is a versatile scaffold and serves as a core structure in many drugs with antimicrobial and other therapeutic effects. In this review, we have updated pyrazole-based antibacterial and antifungal agents mainly developed between 2016 and 2024, by combining with diverse pharmacophores such as coumarin, thiazole, oxadiazole, isoxazole, indole, etc. Meanwhile, the various strategies (molecular hybridization, bioisosterism, scaffold hopping, multicomponent reactions, and catalyst-free synthesis) for integrating different functional groups with the pyrazole ring are discussed. Additionally, structure-activity relationships of these pyrazole derivatives, i.e., how structural modifications impact their selectivity and therapeutic potential against bacterial and fungal strains, are highlighted. This review provides insights into designing next-generation antimicrobials to combat AMR, and offers valuable perspectives to the scientists working on heterocyclic compounds with diverse bioactivities.

Phenol (bio)isosteres in drug design and development

Due to their versatile properties, phenolic compounds are integral to various biologically active molecules, including many pharmaceuticals. However, their application in drug design is often hindered by issues such as poor oral bioavailability, rapid metabolism, and potential toxicity. This review explores the use of phenol bioisosteres-structurally similar compounds that can mimic the biological activity of phenols while potentially offering improved drug-like properties. We provide an extensive analysis of various phenol bioisosteres, including benzimidazolones, benzoxazolones, indoles, quinolinones, and pyridones, highlighting their impact on the pharmacokinetic and pharmacodynamic profiles of drugs. Case studies illustrate the successful application of these bioisosteres in enhancing metabolic stability, receptor selectivity, and overall therapeutic efficacy. Additionally, the review addresses the challenges associated with phenol bioisosterism, such as maintaining potency and avoiding undesirable side effects. By offering a detailed examination of current strategies and potential future directions, this review serves as a valuable resource for medicinal chemists seeking to optimize phenolic scaffolds in drug development. The insights provided herein aim to facilitate the design of more effective and safer therapeutic agents through strategic bioisosteric modifications.

Discovery of Novel Coumarin Pleuromutilin Derivatives as Potent Anti-MRSA Agents

Treating methicillin-resistant Staphylococcus aureus (MRSA) infection remains one of the most difficult challenges in clinical practice, primarily due to the resistance of MRSA to multiple antibiotics. Therefore, there is an urgent need to develop novel antibiotics with high efficacy and low cross-resistance rates. In this study, a series of novel pleuromutilin derivatives with coumarin structures were synthesized and subsequently assessed for their biological activities. Most of these derivatives showed potent antimicrobial activity against drug-resistant Gram-positive bacterial strains. Compound 14b displayed particularly rapid bactericidal effects, slow resistance development, and low cytotoxicity. Moreover, it decreased bacterial loads in the lung, liver, kidney, spleen, and heart and exhibited better antibacterial efficacy (ED50 = 11.16 mg/kg) than tiamulin (ED50 = 28.93 mg/kg) in a mouse model of systemic MRSA infection. Both in vitro and in vivo analyses suggest that compound 14b is a promising agent for the treatment of MRSA infections.

Synthesis biological evaluation and molecular docking of isatin hybrids as anti-cancer and anti-microbial agents

Isatin, known as 1H-indole-2,3-dione, was originally recognised as a synthetic molecule until its discovery in the fruits of the cannonball tree, Couroupita guianensis. It is naturally occurring in plants of the genus Isatis and serves as a metabolic derivative of adrenaline in humans. Isatin possesses significant pharmacological importance, and its synthetic versatility has prompted extensive interest in its derivative compounds due to their diverse biological and pharmacological properties. These derivatives represent a valuable class of heterocyclic compounds with potential applications as precursors for synthesizing numerous valuable drugs. In the pursuit of advancing our research on isatin hybrids, we investigate the utilisation of readily available hydrazonoindolin-2-one and isatin as starting materials for the synthesis of a wide range of analogues. Characterisation of the synthesized compounds was carried out through various analytical techniques. Furthermore, the obtained compounds were subjected to extensive testing to evaluate their anticancer and antimicrobial activities. Specifically, their efficacy against key proteins, namely Staphylococcus aureus protein (PDB ID: 1JIJ), Escherichia coli protein (PDB ID: 1T9U), Pseudomonas aeruginosa protein (PDB ID: 2UV0), and Acinetobacter baumannii protein (PDB ID: 4HKG), was examined through molecular docking calculations. Several molecules, such as 3, 4, 6, 16, and 19, displayed remarkable activity against the renal cancer cell line UO-31. Additionally, the results of antimicrobial activity testing revealed that compound 16 exhibited significant cytotoxicity against Candida albicans and Cryptococcus neoformans. Subsequently, ADME/T calculations were performed to gain insights into the potential effects and reactions of these molecules within human metabolism. This comprehensive study provides valuable insights into the potential pharmacological applications of isatin derivatives and underscores their significance in drug development.

Photocatalytic One-Pot Three-Component Reaction for the Regioselective Synthesis of Bromo-Substituted Pyrazoles

A photocatalytic three-component cascade reaction of readily available enaminones, hydrazines, and CBr4 for the synthesis of bromo-substituted pyrazoles in one pot has been demonstrated. This strategy involves intermolecular C-N/C-Br bond formation and represents an efficient approach to the construction of 4-bromo-substituted pyrazoles with high regioselectivity, broad substrate scope, good functional group tolerance, convenient operation, and mild reaction conditions. Mechanistic investigations show that this reaction proceeds via intermolecular cyclization of enaminones with hydrazines, followed by a regioselective bromination of pyrazoles using CBr4 as a "Br" source.

Design, synthesis, and biological evaluation of pyrazole-ciprofloxacin hybrids as antibacterial and antibiofilm agents against Staphylococcus aureus

In our continued efforts to tackle antibiotic resistance, a new series of pyrazole-ciprofloxacin hybrids were designed, synthesized, and evaluated for their antibacterial activity against Staphylococcus aureus (S. aureus), Pseudomonas aeruginosa (P. aeruginosa), and Mycobacterium tuberculosis (Mtb). Most of the compounds exhibited good to excellent activities against S. aureus, and six compounds (7a, 7b, 7d, 7g, 7k, and 7p) exhibited higher or comparable activity (MIC = 0.125-0.5 μg mL-1) to ciprofloxacin (0.125 μg mL-1). Further, these selected compounds were non-toxic (CC50 ≥ 1000 μg mL-1) when evaluated for cell viability test against the Hep-G2 cell line. Three compounds (7a, 7d, and 7g) demonstrated excellent activity against ciprofloxacin-resistant S. aureus with MIC values ranging from 0.125-0.5 μg mL-1 and good antibiofilm activity. Among them, 7g displayed remarkable antibiofilm activity with an MBIC50 value of 0.02 μg mL-1, which is 50 times lower than ciprofloxacin (MBIC50 = 1.06 μg mL-1). A time-kill kinetics study indicated that 7g showed both concentration and time-dependent bactericidal properties. In addition, 7g effectively inhibited DNA-gyrase supercoiling activity at 1 μg mL-1 (8× MIC). Two compounds 7b and 7d exhibited the highest activity against Mtb with a MIC of 0.5 μg mL-1, while 7c showed the highest activity against P. aeruginosa with a MIC value of 2 μg mL-1. Molecular docking studies revealed that 7g formed stable interactions at the DNA active site.

Photochemical Synthesis of Sericin-Coated Gold Nanorods and Their Antibacterial Activity under Low-Level Near-Infrared Light

Gold nanorods (GNRs) are unique nanoparticles with easily functionalized surfaces, multiple synthesis methods, photothermal conversion, and surface plasmon resonance effects. These properties make GNRs suitable for various biological applications. However, a rapid synthesis of GNRs using less toxic chemicals is needed. The photochemical method is a viable option that can synthesize GNRs quickly while using fewer chemicals. A photochemical method is reported for the synthesis of GNRs using Irgacure-2959 as a reducing agent. This method could be used to synthesize GNRs with a rod-like shape within 30 min. Additionally, GNRs were coated with sericin (GNRs-SC) to further reduce their toxicity in human dermal fibroblast adult cells. Low-level near-infrared (NIR) light was applied to enhance the photothermal therapy of both GNRs and GNRs-SC. The results showed that GNRs and GNRs-SC under low-level NIR light have enhanced antibacterial activity against Staphylococcus aureus and Escherichia coli, as well as antibiofilm activity against S. aureus. Furthermore, GNRs-SC showed good biocompatibility with antibacterial and antibiofilm activities. These results indicate that GNRs-SC are good candidates for various biological applications.

Design, synthesis of griseofamine A derivatives and development of potent antibacterial agents against MRSA

The prevalence of methicillin-resistant Staphylococcus aureus (MRSA), one of the most important multidrug-resistant bacteria in clinic, has become a serious global health issue. In this study, we designed and synthesized a series of griseofamine A derivatives and evaluated their antibacterial profiles. In vitro assays found that compound 9o10 showed a remarkable improvement of antibacterial activity toward MRSA (MIC = 0.0625 μg/mL), compared with griseofamine A (MIC = 8 μg/mL) and vancomycin (MIC = 0.5 μg/mL) with low hemolysis and cytotoxicity. Its rapid bactericidal property was also confirmed by time-kill curve assay. Furthermore, compound 9o10 displayed weak drug resistance frequency. In in vivo experiment, compound 9o10 exhibited more potent antibacterial efficacy than vancomycin and excellent biosafety (LD50 > 2 g/kg). Preliminary mechanism study revealed compound 9o10 might involve antibacterial mechanisms contributing to membrane damage. Taken together, compound 9o10 possessed excellent inhibitory activity against MRSA in vitro and in vivo with low toxicity and drug resistance frequency, making it a promising hit compound for further development against MRSA infections.

Design and synthesis of unique indole-benzosulfonamide oleanolic acid derivatives as potent antibacterial agents against MRSA

The rapid emergence of antibiotic resistance and the scarcity of novel antibacterial agents have necessitated an urgent pursuit for the discovery and development of novel antibacterial agents against multidrug-resistant bacteria. This study involved the design and synthesis of series of novel indole-benzosulfonamide oleanolic acid (OA) derivatives, in which the indole and benzosulfonamide pharmacophores were introduced into the OA skeleton semisynthetically. These target OA derivatives show antibacterial activity against Staphylococcus strains in vitro and in vivo. Among them, derivative c17 was the most promising antibacterial agent while compared with the positive control of norfloxacin, especially against methicillin-resistant Staphylococcus aureus (MRSA) in vitro. In addition, derivative c17 also showed remarkable efficacy against MRSA-infected murine skin model, leading to a significant reduction of bacterial counts during this in vivo study. Furthermore, some preliminary studies indicated that derivative c17 could effectively inhibit and eradicate the biofilm formation, disrupt the integrity of the bacterial cell membrane. Moreover, derivative c17 showed low hemolytic activity and low toxicity to mammalian cells of NIH 3T3 and HEK 293T. These aforementioned findings strongly support the potential of novel indole-benzosulfonamide OA derivatives as anti-MRSA agents.

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.

Synthesis, Structure, and Properties of a Copper(II) Binuclear Complex Based on Trifluoromethyl Containing Bis(pyrazolyl)hydrazone

A new complex of copper(II) with methyl-5-(trifluoromethyl)pyrazol-3-yl-ketazine (H2L) was synthesized with the composition [Cu2L2]∙C2H5OH (1). Recrystallization of the sample from DMSO yielded a single crystal of the composition [Cu2L2((CH3)2SO)] (2). The coordination compounds were studied by single-crystal X-ray diffraction analysis, IR spectroscopy, and static magnetic susceptibility method. The data obtained indicate that the polydentate ligand is coordinated by both acyclic nitrogen and heterocyclic nitrogen atoms. The cytotoxic activity of the ligand and complex 1 was investigated on human cell lines MCF7 (breast adenocarcinoma), Hep2 (laryngeal carcinoma), A549 (lung carcinoma), HepG2 (hepatocellular carcinoma), and MRC5 (non-tumor lung fibroblasts). The complex was shown to have a pronounced dose-dependent cytotoxicity towards these cell lines with LC50 values in the range of 0.18-4.03 μM.

Alanazi M, El Yazidi M. Efficient Synthesis, Structural Characterization, Antibacterial Assessment, ADME-Tox Analysis, Molecular Docking and Molecular Dynamics Simulations of New Functionalized Isoxazoles

This work describes the synthesis, characterization, and in vitro and in silico evaluation of the biological activity of new functionalized isoxazole derivatives. The structures of all new compounds were analyzed by IR and NMR spectroscopy. The structures of 4c and 4f were further confirmed by single crystal X-ray and their compositions unambiguously determined by mass spectrometry (MS). The antibacterial effect of the isoxazoles was assessed in vitro against Escherichia coli, Bacillus subtilis, and Staphylococcusaureus bacterial strains. Isoxazole 4a showed significant activity against E. coli and B. subtilis compared to the reference antibiotic drugs while 4d and 4f also exhibited some antibacterial effects. The molecular docking results indicate that the synthesized compounds exhibit strong interactions with the target proteins. Specifically, 4a displayed a better affinity for E. coli, S. aureus, and B. subtilis in comparison to the reference drugs. The molecular dynamics simulations performed on 4a strongly support the stability of the ligand-receptor complex when interacting with the active sites of proteins from E. coli, S. aureus, and B. subtilis. Lastly, the results of the Absorption, Distribution, Metabolism, Excretion and Toxicity Analysis (ADME-Tox) reveal that the molecules have promising pharmacokinetic properties, suggesting favorable druglike properties and potential therapeutic agents.

New 1,3-diphenyl-1H-pyrazol-5-ols as anti-methicillin resistant Staphylococcus aureus agents: Synthesis, antimicrobial evaluation and in silico studies

In the present work, two hybrid series of pyrazole-clubbed pyrimidine and pyrazole-clubbed thiazole compounds 3-21 from 4-acetyl-1,3-diphenyl-1H-pyrazole-5(4H)-ole 1 were synthesized as novel antimicrobial agents. Their chemical structures were thoroughly elucidated in terms of spectral analyses such as IR, 1H NMR, 13C NMR and mass spectra. The compounds were in vitro evaluated for their antimicrobial efficiency against various standard pathogen strains, gram -ive bacteria (Pseudomonas aeruginosa, Klebsiella pneumonia), gram + ive bacteria (MRSA, Bacillus subtilis), and Unicellular fungi (Candida albicans) microorganisms. The ZOI results exhibited that most of the tested molecules exhibited inhibition potency from moderate to high. Where compounds 7, 8, 12, 13 and 19 represented the highest inhibition potency against most of the tested pathogenic microbes comparing with the standard drugs. In addition, the MIC results showed that the most potent molecules 7, 8, 12, 13 and 19 showed inhibition effect against most of the tested microbes at low concentration. Moreover, the docking approach of the newly synthesized compounds against DNA gyrase enzyme was performed to go deeper into their molecular mechanism of antimicrobial efficacy. Further, computational investigations to calculate the pharmacokinetics parameters of the compounds were performed. Among them 7, 8, 12, 13 and 19 are the most potent compounds revealed the highest inhibition efficacy against most of the tested pathogenic microbes comparing with the standard drugs.

Design, synthesis and biological evaluation of novel pyrazole-based compounds as potential chemotherapeutic agents

Aim: Design and synthesis of pyrazole-based chemotherapeutic agents. Materials & methods: A series of novel diphenyl pyrazole-chalcone derivatives were synthesized and assessed for their cytotoxic activities against 14 cancer cell lines and their antimicrobial activities against MRSA and Escherichia coli along with their safety using HSF normal cell line. Results & conclusion: Majority of the compounds showed moderate-to-significant anticancer activity with selective high percentage inhibition (>80%) against HNO-97 while being nontoxic toward normal cells. Compounds 6b and 6d were the most potent congeners with IC50 of 10 and 10.56 μM respectively. The synthesized compounds exhibited moderate to potent antimicrobial activities. Interestingly, compound 6d exhibited a minimum inhibitory concentration of 15.7 μg/ml against MRSA; and a minimum inhibitory concentration of 7.8 μg/ml versus E. coli.

DHTPY-Cu@ZOL-Enhanced Photodynamic Therapy: A Strategic Platform for Advanced Treatment of Drug-Resistant Bacterial Wound Infections

Purpose

This research was to innovate a nanozyme-based therapeutic strategy that combines aggregation-induced emission (AIE) photosensitizers with copper nanozymes. This approach is designed to address the hypoxic conditions often found in bacterial infections and aims to boost the effectiveness of photodynamic therapy (PDT) by ensuring sufficient oxygen supply for reactive oxygen species (ROS) generation.

Methods

Our approach involved the synthesis of dihydroxyl triphenyl vinyl pyridine (DHTPY)-Cu@zoledronic acid (ZOL) nanozyme particles. We initially synthesized DHTPY and then combined it with copper nanozymes to form the DHTPY-Cu@ZOL composite. The nanozyme's size, morphology, and chemical properties were characterized using various techniques, including dynamic light scattering, transmission electron microscopy, and X-ray photoelectron spectroscopy. We conducted a series of in vitro and in vivo tests to evaluate the photodynamic, antibacterial, and wound-healing properties of the DHTPY-Cu@ZOL nanozymes, including their oxygen-generation capacity, ROS production, and antibacterial efficacy against methicillin-resistant Staphylococcus aureus (MRSA).

Results

The DHTPY-Cu@ZOL exhibited proficient H2O2 scavenging and oxygen generation, crucial for enhancing PDT in oxygen-deprived infection environments. Our in vitro analysis revealed a notable antibacterial effect against MRSA, suggesting the nanozymes' potential to disrupt bacterial cell membranes. Further, in vivo studies using a diabetic rat model with MRSA-infected wounds showed that DHTPY-Cu@ZOL markedly improved wound healing and reduced bacterial presence, underscoring its efficacy as a non-antibiotic approach for chronic infections.

Conclusion

Our study suggests that DHTPY-Cu@ZOL is a highly promising approach for combating antibiotic-resistant microbial pathogens and biofilms. The biocompatibility and stability of these nanozyme particles, coupled with their improved PDT efficacy position them as a promising candidate for clinical applications.

New Antibacterial 1,3,4-Thiadiazole Derivatives With Pyridine Moiety

1,3,4-Thiadiazole compounds were synthesized using pyridine carboxylic acid derivatives and thiosemicarbazide derivatives. The molecular structures of the resulting compounds were characterized by spectroscopic methods such as ATR-FTIR, 1H-NMR, and elemental analysis. Its compounds were also examined for their antibacterial properties against some strains of bacteria. Five synthesized compounds showed varying antibacterial effects on Escherichia coli, Salmonella kentucky, Bacillus substilis and Klebsiella pneumoniae. This result revealed that some of the resulting compounds could be antibacterial agents.

Identification of CH2-linked quinolone-aminopyrimidine hybrids as potent anti-MRSA agents: Low resistance potential and lack of cross-resistance with fluoroquinolone antibiotics

The structural optimization of B14, an antibacterial agent we previously obtained, has led to the discovery of a new class of CH2-linked quinolone-aminopyrimidine hybrids with potent anti-MRSA activities. Surprisingly, the hybrids lacking a C-6 fluoro atom at the quinolone nucleus showed equal or even stronger anti-MRSA activities than their corresponding 6-fluoro counterparts, despite the well-established structure-activity relationships (SARs) indicating that the 6-fluoro substituent enhances the antibacterial activity in conventional fluoroquinolone antibiotics. Moreover, these new hybrids, albeit structurally related to conventional fluoroquinolones, showed no cross-resistance with fluoroquinolone drugs. The most active compound, 15m, exhibited excellent activities with a MIC value of 0.39 μg/mL against both fluoroquinolone-sensitive strain USA500 and -resistant MRSA isolate Mu50. Further resistance development studies indicated MRSA is unlikely to acquire resistance against 15m. Moreover, 15m displayed favorable in vivo half-life and safety profiles. These findings suggest a rationale for further evolution of quinolone antibiotics with a high barrier to resistance.

Natural Polymer-Polyphenol Bioadhesive Coacervate with Stable Wet Adhesion, Antibacterial Activity, and On-Demand Detachment

Medical adhesives are emerging as an important clinical tool as adjuvants for sutures and staples in wound closure and healing and in the achievement of hemostasis. However, clinical adhesives combining cytocompatibility, as well as strong and stable adhesion in physiological conditions, are still in demand. Herein, a mussel-inspired strategy is explored to produce adhesive coacervates using tannic acid (TA) and methacrylate pullulan (PUL-MA). TA|PUL-MA coacervates mainly comprise van der Waals forces and hydrophobic interactions. The methacrylic groups in the PUL backbone increase the number of interactions in the adhesives matrix, resulting in enhanced cohesion and adhesion strength (72.7 Jm-2), compared to the non-methacrylated coacervate. The adhesive properties are kept in physiologic-mimetic solutions (72.8 Jm-2) for 72 h. The photopolymerization of TA|PUL-MA enables the on-demand detachment of the adhesive. The poor cytocompatibility associated with the use of phenolic groups is here circumvented by mixing reactive oxygen species-degrading enzyme in the adhesive coacervate. This addition does not hamper the adhesive character of the materials, nor their anti-microbial or hemostatic properties. This affordable and straightforward methodology, together with the tailorable adhesivity even in wet environments, high cytocompatibility, and anti-bacterial activity, enables foresee TA|PUL-MA as a promising ready-to-use bioadhesive for biomedical applications.

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.

Sulfur (SⅥ)-containing heterocyclic hybrids as antibacterial agents against methicillin-resistant Staphylococcus aureus (MRSA) and its SAR

The discovery of new small molecule-based inhibitors is an attractive field in medicinal chemistry. Structurally diversified heterocyclic derivatives have been investigated to combat multi-drug resistant bacterial infections and they offers several mechanism of action. Methicillin-resistant Staphylococcus aureus (MRSA) is becoming more and more deadly to humans because of its simple method of transmission, quick development of antibiotic resistance, and ability to cause hard-to-treat skin and filmy diseases. The sulfur (SVI) particularly sulfonyl and sulfonamide based heterocyclic moieties, have found to be good anti-MRSA agents. The development of new nontoxic, economical and highly active sulfur (SVI) containing derivatives has become hot research topics in drug discovery research. Presently, more than 150 FDA approved Sulfur (SVI)-based drugs are available in the market, and they are widely used to treat various types of diseases with different therapeutic potential. The present collective data provides the latest advancements in Sulfur (SVI)-hybrid compounds as antibacterial agents against MRSA. It also examines the outcomes of in-vitro and in-vivo investigations, exploring potential mechanisms of action and offering alternative perspectives on the structure-activity relationship (SAR). Sulfur (SVI)-hybrids exhibits synergistic effects with existing drugs to provide antibacterial action against MRSA.

Synthesis, molecular docking analysis, drug-likeness evaluation, and inhibition potency of new pyrazole-3,4-dicarboxamides incorporating sulfonamide moiety as carbonic anhydrase inhibitors

A series of novel pyrazole-dicarboxamides were synthesized from pyrazole-3,4-dicarboxylic acid chloride and various primary and secondary sulfonamides. The structures of the new compounds were confirmed by FT-IR, 1H-NMR, 13C-NMR, and HRMS. Then the inhibition effects of newly synthesized molecules on human erythrocyte hCA I and hCA II isoenzymes were investigated. Ki values of the compounds were in the range of 0.024-0.496 µM for hCA I and 0.006-5.441 µM for hCA II. Compounds 7a and 7i showed nanomolar level of inhibition of hCA II, and these compounds exhibited high selectivity for this isoenzyme. Molecular docking studies were performed between the most active compounds 7a, 7b, 7i, and the reference inhibitor AAZ and the hCAI and hCAII to investigate the binding mechanisms between the compounds and the isozymes. These compounds showed better interactions than the AAZ. ADMET and drug-likeness analyses for the compounds have shown that the compounds can be used pharmacologically in living organisms.

Synthesis and Application of Task-Specific Bimetal-Organic Frameworks in the Synthesis of Biological Active Spiro-Oxindoles

The use of click chemistry as a smart and suitable method for the development of new heterogeneous catalysts is based on metal-organic frameworks as well as the production of organic compounds. The development of the click chemistry method can provide a new strategy to achieve superior properties of MOFs. Here, the two metals Co and Fe are used to create a bimetallic-organic framework. In the following, the click chemistry and postmodification method are well organized and an acidic heterogeneous porous catalyst is developed. This prepared catalyst was used as a highly efficient catalyst for the preparation of new spiro-oxindoles obtained through click chemistry with good to excellent yields (80-94%). This presented catalytic system can compete with the best reported catalytic systems. The findings showed that the presence of Co and Fe metals in the MOF, and the presence of the triazole ring on the catalyst, can increase the catalytic efficiencies. This study offers novel insights into the architecture of Metal-Organic Frameworks (MOFs), click chemistry, and biologically active compounds. Additionally, the research explores the antibacterial properties of the synthesized spiro-oxindoles and catalysts. The findings reveal significant antibacterial activities of the synthesized compounds against S. aureus, MRSA, and E. coli bacteria.

Direct Growth Control of Antibiotic-Resistant Bacteria Using Visible-Light-Responsive Novel Photoswitchable Antibiotics

In addition to the discovery of new (modified) potent antibiotics to combat antibiotic resistance, there is a critical need to develop novel strategies that would restrict their off-target effects and unnecessary exposure to bacteria in our body and environment. We report a set of new photoswitchable arylazopyrazole-modified norfloxacin antibiotics that present a high degree of bidirectional photoisomerization, impressive fatigue resistance and reasonably high cis half-lives. The irradiated isomers of most compounds were found to exhibit nearly equal or higher antibacterial activity than norfloxacin against Gram-positive bacteria. Notably, against norfloxacin-resistant S. aureus bacteria, the visible-light-responsive p-SMe-substituted derivative showed remarkably high antimicrobial potency (MIC of 0.25 μg/mL) in the irradiated state, while the potency was reduced by 24-fold in case of its non-irradiated state. The activity was estimated to be retained for more than 7 hours. This is the first report to demonstrate direct photochemical control of the growth of antibiotic-resistant bacteria and to show the highest activity difference between irradiated and non-irradiated states of a photoswitchable antibiotic. Additionally, both isomers were found to be non-harmful to human cells. Molecular modellings were performed to identify the underlying reason behind the high-affinity binding of the irradiated isomer to topoisomerase IV enzyme.

Discovery of Unique Bis-Substituted Aromatic Amide Derivatives as Novel Highly Potent Antibiotics for Combating Methicillin-Resistant Staphylococcus aureus (MRSA)

Due to the increasing antibiotic resistance, developing novel antimicrobials to fight infections caused by resistant bacteria is imperative. Herein, a series of novel bis-substituted aromatic amides were designed and synthesized through modifying the hit compound 1, and their antimicrobial activities were evaluated. Among them, compound 4t, as the most potent lead, exhibited excellent antimicrobial activities against Gram-positive bacteria, including clinical methicillin-resistant Staphylococcus aureus (MRSA) isolates, while keeping weak hemolytic and mammalian cytotoxic activities. Furthermore, compound 4t displayed rapid bactericidal capabilities, low tendency to produce resistance, and favorable capacities to destroy bacterial biofilms. Further explorations indicated that compound 4t induces bacterial death by binding to cardiolipin (CL) on the bacterial membrane, disrupting the cell membrane, and facilitating the accumulation of reactive oxygen species (ROS). Additionally, compound 4t showed remarkable anti-MRSA activity in vivo, demonstrating compound 4t could be developed as a potential candidate to combat MRSA infections.

Fluorinated azoles as effective weapons in fight against methicillin-resistance staphylococcus aureus (MRSA) and its SAR studies

The rapid spread of Methicillin-resistant Staphylococcus aureus (MRSA) and its difficult-to-treat skin and filmsy diseases are making MRSA a threat to human life. The most dangerous feature is the fast emergence of MRSA resistance to all recognized antibiotics, including vancomycin. The creation of novel, effective, and non-toxic drug candidates to combat MRSA isolates is urgently required. Fluorine containing small molecules have taken a centre stage in the field of drug development. Over the last 50 years, there have been a growing number of fluorinated compounds that have been approved since the clinical usage of fluorinated corticosteroids in the 1950 s and fluoroquinolones in the 1980 s. Due to its advantages in terms of potency and ADME (absorption, distribution, metabolism, and excretion), fluoro-pharmaceuticals have been regarded as a potent and useful tool in the rational drug design method. The flexible bioactive fluorinated azoles are ideal candidates for the development of new antibiotics. This review summarizes the decade developments of fluorinated azole derivatives with a wide antibacterial activity against diverged MRSA strains. In specific, we correlated the efficacy of structurally varied fluorinated azole analogues including thiazole, benzimidazole, oxadiazole and pyrazole against MRSA and discussed different angles of structure-activity relationship (SAR).

Regioselective Synthesis of Cycloalkane-fused Pyrazolo[4,3-e]pyridines through Tandem Reaction of 5-aminopyrazoles, Cyclic Ketones and Electron-rich Olefins

BACKGROUND

Pyrazolopyridines are interesting fused heterocyclic pharmacophores that combine pyrazole and pyridine; two privileged nuclei extensively studied and with a wide range of applications. They can be obtained by a broad variety of synthetic methods among which multicomponent reactions have gained importance, especially from 5-aminopyrazoles and dielectrophilic reagents. However, the search for new approaches more in tune with sustainable chemistry and the use of unconventional heating in three-component synthesis are open and highly relevant study fields.

METHODS

A novel, practical and efficient three-component synthesis of cycloalkane-fused pyrazolo[ 4,3-e]pyridines was developed through a tandem reaction of 5-aminopyrazoles, cyclic ketones and electron-rich olefins, using microwave induction in perfluorinated solvent and iodine as catalyst.

RESULTS

The microwave-induced three-component approach applied in this work promoted the construction of 10 new pyrazolopyridines with high speed and excellent control of regioselectivity, favoring the linear product with good yields; where the versatility of electron-rich olefins in iodine-catalyzed cascade heterocyclizations, granted the additional benefit of easy isolation and the possibility to reuse the fluorous phase.

CONCLUSION

Although pyrazolopyridines have been synthetically explored because of their structural and biological properties, most of the reported synthetic methods use common or even toxic organic solvents and conventional heating or multi-step processes. In contrast, this study applied a multicomponent methodology in a single step by microwave induction and with the versatility provided in this case by the use of perfluorinated solvent, which allowed easy isolation of the final product and recovery of the fluorous phase.

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.

Discovery of novel cannabidiol derivatives with augmented antibacterial agents against methicillin-resistant Staphylococcus aureus

Drug-resistant bacterium infections are a severe threat to public health and novel antimicrobial agents combating drug-resistant bacteria are an unmet medical need. Although cannabidiol (CBD) has been reported to show antibacterial effects, whether its antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA) can be improved remains unclear. Herein, a series of novel CBD derivatives were designed and synthesized using various chemical approaches including amidation, Friedel-Crafts alkylation, and Negishi cross-coupling reaction for the modifications at the C-7, C-2', C-4', and C-6' positions of CBD skeleton. Derivative 21f showed augmented antibacterial activity against MRSA with a minimum inhibitory concentration of 4 μM without cytotoxic effect in microglia BV2 cells. Further mechanistic studies suggested that 21f inhibited the formation of biofilms, induced excess reactive oxygen species, and reduced bacterial metabolism, which collectively led to the acceleration of bacterial death. Findings from this study expand the understanding of CBD derivatives as promising antibacterial agents, which provides useful information for the development of cannabinoid-based antibacterial agents.

New Pyrazole-Clubbed Pyrimidine or Pyrazoline Hybrids as Anti-Methicillin-Resistant Staphylococcus aureus Agents: Design, Synthesis, In Vitro and In Vivo Evaluation, and Molecular Modeling Simulation

Two hybrid series of pyrazole-clubbed pyrimidines 5a-c and pyrazole-clubbed pyrazoline compounds 6a,b and 7 were designed as attractive scaffolds to be investigated in vitro and in vivo for antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa. From the results of the in vitro antibacterial screening, compound 5c showed excellent activity (minimal inhibitory concentration, MIC = 521 μM) when compared with that of the reference antibiotic levofloxacin (MIC = 346 μM). The inhibition of the target dihydrofolate reductase (DHFR) enzyme by compounds 4 and 5a-c (IC50 = 5.00 ± 0.23, 4.20 ± 0.20, 4.10 ± 0.19, and 4.00 ± 0.18 μM, respectively) was found to be better than the reference drug trimethoprim (IC50 = 5.54 ± 0.28 μM). Molecular modeling simulation results have justified the order of activity of all the newly synthesized compounds as DHFR enzyme inhibitors, and compound 5c exhibited the best binding profile (-13.6169386 kcal/mol). Hence, the most potent inhibitor of the DHFR enzyme, 5c, was chosen to be evaluated in vivo for its activity in treating MRSA-induced keratitis in rats and that, in turn, significantly (P < 0.0001) reduced infection in rats when compared to MRSA-treated group results.

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.

The anti-infective potential of the endophytic fungi associated with Allium cepa supported by metabolomics analysis and docking studies

Endophytic fungi are known to be a rich source of anti-infective drugs. In our study, Allium cepa was investigated for fungal diversity using different media to give 11 isolates which were identified morphologically. Out of the isolated fungal strains, Penicillium sp. (LCEF10) revealed potential anti-infective activity against the tested microbes (Fusarium solani ATTC 25922, Pseudomonas aeruginosa (ATTC 29231), Staphylococcus aureus ATTC 27853, Candida albicans ATTC 10231), besides, their MICs were measured by well diffusion method, therefore, it was subjected to molecular identification in addition to phylogenetic analysis. Moreover, the ITS sequence of strain LCEF10 showed a consistent assignment with the highest sequence similarity (99.81%) to Penicillium oxalicum NRRL 787. The crude ethyl acetate extract of Penicillium sp. LCEF10 was investigated for metabolomic analysis using LC-HR-ESI-MS. The metabolic profiling revealed the presence of polyketides, macrolides, phenolics and terpenoids. Furthermore, in silico molecular docking study was carried out to predict which compounds most likely responsible for the anti-infective activity.

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.

Tailoring the Surface and Composition of Nanozymes for Enhanced Bacterial Binding and Antibacterial Activity

With the advantages of diverse structures, tunable enzymatic activity, and high stability, nanozymes are widely used in medicine, chemistry, food, environment, and other fields. As an alternative to traditional antibiotics, nanozymes attract more and more attention from the scientific researchers in recent years. Developing nanozymes-based antibacterial materials opens up a new avenue for the bacterial disinfection and sterilization. In this review, the classification of nanozymes and their antibacterial mechanisms are discussed. The surface and composition of nanozymes are critical for the antibacterial efficacy, which can be tailored to enhance both the bacterial binding and the antibacterial activity. On the one hand, the surface modification of nanozymes enables binding and targeting of bacteria that improves the antibacterial performance of nanozymes including the biochemical recognition, the surface charge, and the surface topography. On the other hand, the composition of nanozymes can be modulated to achieve enhanced antibacterial performance including the single nanozyme-mediated synergistic and multiple nanozymes-mediated cascade catalytic antibacterial applications. In addition, the current challenges and future prospects of tailoring nanozymes for antibacterial applications are discussed. This review can provide insights into the design of future nanozymes-based materials for the antibacterial treatments.

Facile One-Pot Three Component Synthesis, Characterization, and Molecular Docking Simulations of Novel α-Aminophosphonate Derivatives Based Pyrazole Moiety as Potential Antimicrobial Agent

An efficient method has been developed for the synthesis of novel α-aminophosphonates (AAP) (3 a-m) through a one-pot three-component reaction of 1,3-disubstituted-1H-pyrazol-5-amine, aromatic aldehydes, and phosphite using lithium perchlorate as catalyst. All newly synthesized compounds were characterized via different spectroscopic techniques. The synthesized compounds' mode of action was investigated using molecular docking against the outer membrane protein A (OMPA) and exo-1,3-β-glucanase, with interpreting their pharmacokinetics aspects. The results of the antimicrobial effectiveness of these compounds revealed a broad spectrum of their biocidal activity and this in-vitro study was in line with the in- silico results. Additionally, it has been demonstrated that these compounds exhibited a minimum inhibitory concentration (MIC) with significant activity at low concentrations (7.5-30.0 mg/mL). Further, the radical scavenging (DPPH* ) activity of the synthesized compounds fluctuated, with compounds 3 h, 3 a, and 3 f showing the highest antioxidant activity. Overall, the formulated compounds can be employed as antimicrobial and antioxidant agents in medical applications.

Exploring Three Avenues: Chemo- and Regioselective Transformations of 1,2,4-Triketone Analogs into Pyrazoles and Pyridazinones

A convenient approach to substituted pyrazoles and pyridazinones based on 1,2,4-triketones is presented. Chemo- and regiocontrol in condensations of t-Bu, Ph-, 2-thienyl-, and CO2Et-substituted 1,2,4-triketone analogs with hydrazines are described. The direction of preferential nucleophilic attack was shown to be switched depending on the substituent nature in triketone as well as the reaction conditions. The acid and temperature effects on the selectivity of condensations were revealed. Regiochemistry of heterocyclic core formation was confirmed by NMR and XRD studies. The facile construction of heterocyclic motifs bearing acetyl and (or) carbethoxy groups suggests them as promising mono- or bifunctional building blocks for subsequent transformations.

Synthesis and pharmacological evaluation of 1,3-diaryl substituted pyrazole based (thio)urea derivatives as potent antimicrobial agents against multi-drug resistant Staphylococcus aureus and Mycobacterium tuberculosis

The urgent development of newer alternatives has been deemed a panacea for tackling emerging antimicrobial resistance effectively. Herein, we report the design, synthesis, and biological evaluation of 1,3-diaryl substituted pyrazole-based urea and thiourea derivatives as antimicrobial agents. Preliminary screening results revealed that compound 7a (3,4-dichlorophenyl derivative) exhibited potent activity against S. aureus (MIC = 0.25 μg mL-1) and compound 7j (2,4-difluorophenyl derivative) against Mycobacterium tuberculosis (MIC = 1 μg mL-1). Compounds 7a and 7j were non-toxic to Vero cells with a favorable selectivity index of 40 and 200, respectively, and demonstrated good microsomal stability. Compound 7a exhibited equipotent activity (MIC = 0.25 μg mL-1) against various multidrug-resistant strains of S. aureus, which include various strains of MRSA and VRSA, and elicited bacteriostatic properties. In an enzymatic assay, 7a effectively inhibited DNA gyrase supercoiling activity at a concentration of 8 times MIC. Further, molecular modeling studies suggested that compound 7a binds at the active site of DNA gyrase with good affinity.

New Hybrid Tetrahydropyrrolo[3,2,1-ij]quinolin-1-ylidene-2-thioxothiazolidin-4-ones as New Inhibitors of Factor Xa and Factor XIa: Design, Synthesis, and In Silico and Experimental Evaluation

Despite extensive research in the field of thrombotic diseases, the prevention of blood clots remains an important area of study. Therefore, the development of new anticoagulant drugs with better therapeutic profiles and fewer side effects to combat thrombus formation is still needed. Herein, we report the synthesis and evaluation of novel pyrroloquinolinedione-based rhodanine derivatives, which were chosen from 24 developed derivatives by docking as potential molecules to inhibit the clotting factors Xa and XIa. For the synthesis of new hybrid derivatives of pyrrolo[3,2,1-ij]quinoline-2-one, we used a convenient structural modification of the tetrahydroquinoline fragment by varying the substituents in positions 2, 4, and 6. In addition, the design of target molecules was achieved by alkylating the amino group of the rhodanine fragment with propargyl bromide or by replacing the rhodanine fragment with 2-thioxoimidazolidin-4-one. The in vitro testing showed that eight derivatives are capable of inhibiting both coagulation factors, two compounds are selective inhibitors of factor Xa, and two compounds are selective inhibitors of factor XIa. Overall, these data indicate the potential anticoagulant activity of these molecules through the inhibition of the coagulation factors Xa and XIa.

Nanobubbles: a promising efficient tool for therapeutic delivery of antibacterial agents for the Staphylococcus aureus infections

The current research is focused to address the implementation of nanobubbles technology to antibacterial agents against Staphylococcus aureus infections. Nanobubbles technology is a novel, latest research employed in many medical fields including drug discovery. In this present work, supramolecular nanoliquid formulation of potential antiseptic agent chloroxylenol-based Dettol and its enhanced antibacterial activity, biocompatibility assessment was studied. Nanobubble technology was adopted to prepare nanoformulation (NB-D) using a household hand mixer under thermostatically controlled conditions. A high-stability nanoformulation with high potential antibacterial activity against human pathogenic strains of Pseudomonas aeruginosa and Staphylococcus aureus was produced by the nanobubbles created in the antiseptic solution. The overall vitality of both strains was significantly reduced in all dose tests on NB-D treatment as a result of the antibacterial activity as assessed by the well-diffusion assay, turbidometric microdilution assay, biofilm inhibition assay, and total count reduction assay. Biocompatibility of the NB-D formulation was studied by the determination of cytotoxicity against HaCaT-human keratinocytes and hemocytes. NB-D treatment did not induce any notable cytotoxic effect on HaCaT cells by showing none of the changes in cell morphology and architecture. No toxic effect on the hematocytes was observed in NB-D treatment. The enhanced antibacterial activity and best biocompatibility of NB-D result shows that the nanobubble technology could be used as an effective strategy for the formulation of antiseptics or disinfectants against high health risk infectious organisms. The novelty of the work is the formation of supramolecular nanoformulation on antiseptic agent which promised the results enhanced than the raw antiseptic agent.