Design and synthesis of hybrid compounds as novel drugs and medicines

Design, Synthesis, In Vitro, and In Silico Evaluation of Isoxazole-Isoxazoline Conjugates as Potential Antimicrobial Agents

A new series of hybrid compounds (5a-h) incorporating both isoxazole and isoxazoline scaffolds has been successfully synthesized, characterized, and assessed for their antimicrobial propriety. The newly synthesized conjugates were characterized through various spectroscopic methods, including FT-IR, 1D and 2D NMR, along with mass spectrometry. The conjugate compounds were subsequently evaluated for their antimicrobial activity against the some pathogenic following bacterial strains. Compounds (5a-d) and (5h) demonstrated notable activity in vitro against Escherichia coli, exhibiting an inhibition zone diameter (IZD) of 16 ± 0.74 mm and an inhibition rate of 80%. This activity is comparable to that of ampicillin, which was selected as a standard for comparison. Compound (5c) exhibited notable efficacy against Bacillus subtilis, with an inhibition rate of 50%. Concurrently, compound (5a) was distinguished by its noteworthy antifungal properties, exhibiting an IZD of 21 ± 0.50 mm (77% inhibition), which is comparable to the standard reference amphotericin B. The minimal inhibitory concentration (MIC) tests indicated that the compound (5h) exhibited notable efficacy against E. coli, B. subtilis, and Candida albicans, with MICs of 10, 10, and 60 µg/mL, respectively, approaching the values of the established standards of amphotericin B and ampicillin. Molecular docking analysis revealed favorable binding affinities of compounds (5a-h) against E. coli, B. subtilis, and C. albicans, outperforming conventional antibiotics. Molecular dynamics simulations were carried out on (5h), the most effective antibacterial and antifungal compound. ADME-Tox evaluation showed high intestinal absorption, especially for (5d) and (5h) (100%), blood retention, and a favorable safety profile with efficient elimination.

Synthesis, cytotoxicity, oxidative stress, anti-metastatic and anti-inflammatory effects of novel 2-methylene-1H-indene-1,3-dione tethered 2-(2-methoxyphenoxy)-N-arylacetamide: induction of apoptosis in HCT116 and HeLa cells

Six novel chalcones were synthesized, and their structures were confirmed using various spectral tools. All the prepared compounds were subjected to SRB cytotoxic screening against nine cancer and two normal cell lines. Compound 7a showed the highest impact against colorectal carcinoma (HCT116) and cervical cancer (HeLa) with IC50 values of 4.6 ± 0.03 and 5.5 ± 0.1 μg/mL, respectively, compared to doxorubicin (4.8 ± 0.4 and 5.7 ± 0.4 μg/mL, respectively). ELISA assay revealed that the apoptotic proteins (P53, Bax, caspases-3, -8, and -9) and the oxidative marker (Malondialdehyde (MDA)) were significantly activated in 7a treated HCT116 and HeLa cells. However, the anti-metastatic markers (Matrix metalloproteinase 2 (MMP2) and Matrix metalloproteinase-9 (MMP9)), anti-apoptotic Bcl2, antioxidant Glutathione (GSH), and anti-inflammatory (interleukin (IL)-6, and IL-1β) were inhibited in HCT116 and HeLa cells treated with 7a. Flow-cytometric analysis of the cell cycle revealed that the percentage of cells in S and G2/M phases in 7a treated HCT116 cells was increased. After 24 h of treatment, Hela-treated cells had a slightly higher proportion of G0/G1 cells. Comet assay demonstrated that compound 7a caused DNA damage with a percentage of 26.22 ± 1.1 % in HCT116 compared to the untreated cells (6.18 ± 0.88 %). Theoretical molecular modeling against P53 cancer mutant Y220C and Bcl2 showed binding energies of -22.7 and -23.3 kcal/mol, respectively, which confirmed our ELISA results.

Synthesis and mechanistic insights of Coumarinyl-Indolinone hybrids as potent inhibitors of Leishmania major

Leishmaniasis, recognized as a neglected tropical disease, is a major global health issue that impacts millions of individuals across the globe. The limitations of existing treatments underscore the urgent need for novel antileishmanial drugs. In response, this study synthesized and evaluated fifteen hybrid compounds (7a-c, 10a-j, and 13a-b) combining 4-hydroxycoumarin and pyrazolyl indolin-2-one motifs for their in vitro antileishmanial efficacy towards Leishmania major. These molecules demonstrated remarkable activity against the promastigote form, with IC50 values ranging from 1.21 to 7.21 μM, surpassing the reference drug miltefosine (IC50 = 7.83 μM). Assessment against the intracellular amastigote form revealed efficient inhibitory action (IC50: 2.41-9.44 μM vs. 8.07 μM for miltefosine). Compounds 7a and 7b exhibited exceptional antileishmanial activity against both forms while maintaining favorable safety profiles. Mechanistic studies indicated that the most effective compounds act through an antifolate mechanism, targeting pteridine reductase 1 (PTR1) and dihydrofolate reductase-thymidylate synthase (DHFR-TS). Molecular docking and dynamics simulations of compounds 7a and 7b revealed strong in-silico binding and stable dynamics against PTR1, suggesting a high potential for enzyme inhibition. These findings present a promising new class of antileishmanial agents targeting the folate pathway.

Pharmacochemical Studies of Synthesized Coumarin-Isoxazole-Pyridine Hybrids

Several new coumarin-isoxazole-pyridine hybrids were synthesized through a 1,3-dipolar cycloaddition reaction of nitrile oxides, prepared in situ from pyridine aldehyde oximes, with propargyloxy- or propargylaminocoumarins in moderate-to-good yields. Synthetic modifications were applied using (diacetoxyiodo)benzene (PIDA) at room temperature, microwave irradiation, or tert-butyl nitrite (TBN) under reflux. Coumarin, isoxazole, and pyridine groups were selected for hybridization in one molecule due to their biological impact to inhibit lipid peroxidation and an enzyme implicated in inflammation. Preliminary in vitro screening tests for lipoxygenase (LOX) inhibition and anti-lipid peroxidation for the new hybrids were performed. A discussion on the structure-activity relationship is presented. Compounds 12b and 13a were found to be potent LOX inhibitors with IC50 5 μΜ and 10 μΜ, respectively, while 12b presented high (90.4%) anti-lipid peroxidation. Furthermore, hybrids 12b and 13a exhibited moderate-to-low anticancer activities on HeLa, HT-29, and H1437 cancer cells.

The Current Landscape of 1,2,3-triazole Hybrids With Anticancer Therapeutic Potential: Part II

Chemotherapy has been identified as a validated and critically important strategy for the treatment of cancer, but multidrug resistance and serious side effects remain grand challenges for effective cancer therapy. This highlights the urgent need for the development of alternative chemical entities that can modulate more than one biological target with high specificity and multitargeted mechanism of action in the disease progression pathway. 1,2,3-Triazole hybrids have the potential to act on dual/multiple targets in cancer cells simultaneously and possess potent broad-spectrum activity against various cancers, including drug-resistant forms. Thus, 1,2,3-triazole hybrids are valuable scaffolds in the treatment and eradication of cancer. This review provides a comprehensive overview of the evolving landscape of 1,2,3-triazole hybrids with their in vitro and in vivo anticancer potential, and the structure-activity relationships as well as mechanisms of action are also discussed, covering articles published from 2021 onward.

A review on pyrimidine-based pharmacophore as a template for the development of hybrid drugs with anticancer potential

The low efficacy and toxicity of traditional chemotherapy, led by drug resistance of targeted anticancer therapies, have mandated the exploration and development of anticancer molecules. In this league, hybrid drugs, owing to their peculiar multitargeted functionality and structural diversity, could serve as vital leads in this quest for drug discovery. They are plausibly found to offer added advantages considering the improved efficacy, low toxicity, and improved patient compliance. Among numerous heterocycles explored, pyrimidine derivatives epitomize as a valuable resource for the hybrid drug development due to their validated efficacy and versatility. The present review discusses the role of pyrimidine, a diversified pharmacophore in drug development and concepts of hybrid drugs. The study covers the recent advancements in pyrimidine-based hybrid pharmacophores. It delves further into the challenges in hybrid drug development and ongoing research in hybrid drug discovery. Furthermore, the challenges faced in developing hybrid molecules, such as their design and optimization complexities, bioavailability and pharmacokinetics issues, target identification and validation, and off-target effects, are discussed.

Therapeutic Potental of Quinolin-2H-one Hybrids as Anticancer Agents

The statistical data related to cancer in recent years has shown a great increase in the number of cases and is likely to further increase in the future. Even after seeking thorough knowledge on the aetiology of cancer and related disorders and attempting to cure it by various methods like gene therapy, T cell therapy, chemotherapy, surgery, hormone therapy, and photodynamic therapy, there has always been disappointment concerning the survival rate. Hence, there is still a great urge for the discovery of novel drugs for the treatment of cancer. Chemotherapy being one of the widely used methods, several drug entities possessing anticancer properties are already in the market but none of them is known to show good efficacy which necessitates researchers to design newer drugs for the treatment of cancer. The urge to synthesize novel anticancer entities directed researchers towards molecular hybridization as one of the novel methods for designing newer drugs. Literature reveals wide research carried out on quinolin-2-one hybrids, possessing anticancer properties through different mechanisms. Tipifarnib and Dovitinib are quinolin-2-one hybrids used to treat cancer, possessing imidazole and benzimidazole heterocyclic rings. Different heterocyclic scaffolds such as pyrone, pyrrole, pyrimidine, pyridine, thiazole, and pyrazole in combination with heterocyclic quinolin-2-one have shown high potential to become lead for newer anticancer agents with better and wider therapeutic properties and lesser side effects. The current review presents information on the different quinolin-2-one hybrids and their effect on different cancer cell lines. It also imparts knowledge of the structural requirements for designing novel anticancer agents.

Maleimide-Dependent Rh(III)-Catalyzed Site-Selective Mono and Dual C-H Functionalization of 2-Arylbenzo[d]thiazole and Oxazole Derivatives

The site-selective functionalization of aromatic compounds via C-H activation has emerged as a popular tool in organic synthesis. In this study, we report a regioselective coupling of maleimide to 2-arylbenzo[d]thiazoles in the presence of a rhodium(III) catalyst. Depending upon the nature of the substituent (R2-group) present in the maleimide substrate, either mono- or bis-1,4-addition products were observed in this methodology. In the case of R2 = aryl, cyclohexyl, and tert-butyl, mono coupling was observed, whereas substituents, such as methyl, ethyl, benzyl, and methyl thiophene, provided bis coupling as the major products. Similar selectivity was also observed in the case of 2-arylbenzo[d]oxazoles.

Isoflavone Derivatives as Potential Anticancer Agents: Synthesis and Bioactivity Studies

Isoflavones are phenolic natural compounds with a C6C3C6 framework. They possess a plethora of biological activities that are associated with putative benefits to human health. In particular, the cancer chemopreventive and chemotherapeutic potential of isoflavones has attracted the interest of researchers. Several isoflavone derivatives have been synthesised and probed for their anticancer activities. The isoflavone analogues are mainly synthesised by molecular hybridisation and other strategies that enable diversification through early or late-stage functionalisation of A-, B- and C-rings of the isoflavones. This has resulted in the discovery of isoflavone analogues with improved antiproliferative activities against several cancer cells and different mechanisms of action. In this review, the synthesis of isoflavone derivatives and their anticancer activity studies are discussed.

Unveiling the antiglioblastoma potential of harmicens, harmine and ferrocene hybrids

The poor prognosis of glioblastoma multiforme, inadequate treatment options, and growing drug resistance urge the need to find new effective agents. Due to the significant anti-cancer potential of harmicens, hybrid compounds which comprise harmine/β-carboline and ferrocene moiety, we investigated their antiglioblastoma potential in vitro and mechanism of action (inhibition of DYRK1A, Hsp90, anti-oxidative activity). The results have shown that triazole-type harmicens, namely 5, with a ferrocene moiety in C-3 position of the β-carboline ring (IC 50 = 3.7 ± 0.1 µmol L-1, SI = 12.6) and ., the C-6 substituted harmicene (IC 50 = 7.4 ± 0.5 µmol L-1, SI = 5.8) exert remarkable activity and selectivity against human malignant glioblastoma cell line (U251) in vitro. On the other hand, amide-type harmicens 10, 12, and 14 exhibited strong, but non-selective activity, in the low micro-molar range. Mechanistic studies revealed that among active compounds, amide-type harmicens 12 and 14 inhibit DYRK1A and Hsp90 CTD, whereas compound 14 showed pronounced antioxidative activity. Therefore, the antiproliferative activity of harmicens might be a combination of complex molecular interactions.

Discovery of new molecular hybrid derivatives with coumarin scaffold bearing pyrazole/oxadiazole moieties: Molecular docking, POM analyses, in silico pharmacokinetics and in vitro antimicrobial evaluation with identification of potent antitumor pharmacophore sites

This synthetic organic methodology involves the creation of novel coumarin-based hybrids of series (1-4) with pyrazole ring and (5-8) with oxadiazole moiety. The targeted compounds were tested for In vitro Antimicrobial efficacy against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Candida albicans pathogenic microbes using disc diffusion and broth microdilution with ciprofloxacin and fluconazole as reference standards. Density functional theory (DFT) studies were used to study atomic structure and reactivity, including absolute electronegativity (χ), electrophilicity (ω), electron acceptor (ω+), donor capabilities (ω-), electron affinity (EA), energy gap (ΔE), global hardness (η), global softness (S), and ionisation potential (IP) and FMOs, NBOs, MEP, and Mulliken Charge analysis. The POM tests found three integrated pharmacophore sites with antibacterial, antiviral, and anticancer activities. Molecular docking studies are also used to determine the S. aureus nucleoside diphosphate kinase receptor's affinity and mode of action for the synthesized drugs. In silico analysis of thermodynamic and therapeutic effectiveness properties, including Lipinski's 'rule of five', Veber's rule, and ADME properties, predicted toxicity-free, non-carcinogenic, and risk-free oral administration of the synthesized complexes.

Novel Antimicrobial and Antitumor Agents Bearing Pyridine-1,2,4-triazole-3-thione-hydrazone Scaffold: Synthesis, Biological Evaluation, and Molecular Docking Investigation

A series of target 4-substituted-5-(2-(pyridine-2-ylamino)ethyl)-2,4-dihydro-3H-1,2,4-triazole-3-thiones and their chloro analogs 7-21 were synthesized in a reaction of the selected aldehydes with the corresponding 4-amino-1,2,4-triazole-3-thiones 5 and 6, which were obtained from 3-(pyridin-2-ylamino)propanoic acid (3) or 3-((5-chloropyridin-2-yl)amino)propanoic acid (4), respectively, with thioacetohydrazide. The antibacterial and antifungal activities of the synthesized hydrazones were screened against the bacteria Escherichia coli, Staphylococcus aureus, and Mycobacterium luteum and the fungi Candida tenuis and Aspergillus niger by agar diffusion and serial dilution methods. 4-Amino-5-(2-((5-chloropyridin-2-yl)amino)ethyl)-2,4-dihydro-3H-1,2,4-triazole-3-thione (6) and 4-(benzylideneamino)-5-(2-(pyridin-2-ylamino)ethyl)-2,4-dihydro-3H-1,2,4-triazole-3-thione (7) were identified as exceptionally active (MIC 0.9 µg/mL) against the fungus C. tenuis. 5-Chloropyridine derivatives bearing 4-benzylidene 8, 2-nitrobenzylidene 10, pyridinylmethylene 16, and 4-methylthiobenzylidene 21 moieties showed very high antibacterial activity (MIC 3.9 µg/mL) against the M. luteum strain. The cell viability screening of the synthesized compounds using triple-negative breast cancer MDA-MB-231 and glioblastoma U-87 cell lines by MTT assay identified three active hydrazones, of which 5-(2-(pyridin-2-ylamino)ethyl)-4-((pyridin-3-ylmethylene)amino)-2,4-dihydro-3H-1,2,4-triazole-3-thione (15) had the highest effect on the viability of cells (IC50 value 39.2 ± 1.7 μM against MDA-MD-231). The in silico molecular modeling results suggested that these three most active hydrazones might have influenced the mitogen-activated protein kinase pathway through the inhibition of BRAF and MEK serine-threonine protein kinases. 5-(2-((5-Chloropyridin-2-yl)amino)ethyl)-4-((4-(methylthio)benzylidene)amino)-2,4-dihydro-3H-1,2,4-triazole-3-thione (21) demonstrated the highest affinity among them.

Molecular exploration of natural and synthetic compounds databases for promising hypoxia inducible factor (HIF) Prolyl-4- hydroxylase domain (PHD) inhibitors using molecular simulation and free energy calculations

Hypoxia-inducible factors (HIFs) are transcription factors that regulate erythropoietin (EPO) synthesis and red blood cell (RBC) production. Prolyl-4-hydroxylase domain (PHD) enzymes are key regulators of HIF's stability and activity. Inhibiting PHD enzymes can enhance HIF-mediated responses and have therapeutic potential for diseases such as anemia, cancer, stroke, ischemia, neurodegeneration, and inflammation. In this study, we searched for novel PHD inhibitors from four databases of natural products and synthetic compounds: AfroDb Natural Products, AnalytiCon Discovery Natural Product (NP), HIM-Herbal Ingredients In-Vivo Metabolism, and Herbal Ingredients' Targets, with a total number of 13,597 compounds. We screened the candidate compounds by molecular docking and validated them by molecular dynamics simulations and free energy calculations. We identified four target hits (ZINC36378940, ZINC2005305, ZINC31164438, and ZINC67910437) that showed stronger binding affinity to PHD2 compared to the positive control, Vadadustat (AKB-6548), with docking scores of - 13.34 kcal/mol, - 12.76 kcal/mol, - 11.96 kcal/mol, - 11.41 kcal/mol, and - 9.04 kcal/mol, respectively. The target ligands chelated the active site iron and interacted with key residues (Arg 383, Tyr329, Tyr303) of PHD2, in a similar manner as Vadadustat. Moreover, the dynamic stability-based assessment revealed that they also exhibited stable dynamics and compact trajectories. Then the total binding free energy was calculated for each complex which revealed that the control has a TBE of - 31.26 ± 0.30 kcal/mol, ZINC36378940 reported a TBE of - 38.65 ± 0.51 kcal/mol, for the ZINC31164438 the TBE was - 26.16 ± 0.30 kcal/mol while the ZINC2005305 complex reported electrostatic energy of - 32.75 ± 0.58 kcal/mol. This shows that ZINC36378940 is the best hit than the other and therefore further investigation should be performed for the clinical usage. Our results suggest that these target hits are promising candidates that reserve further in vitro and in vivo validations as potential PHD inhibitors for the treatment of renal anemia, cancer, stroke, ischemia, neurodegeneration, and inflammation.

Design, synthesis and biological evaluation of multitarget hybrid molecules containing NHC-Au(I) complexes and carbazole moieties

N-heterocyclic carbenes (NHCs) represent suitable ligands for rapid and efficient drug design, because they offer the advantage of being easily chemically modified and can bind several substituents, including transition metals as, for instance, gold derivatives. Gold-NHC complexes possess various biological activities and were demonstrated good candidates as anticancer drugs. Besides, carbazole derivatives are characterized by various pharmacological properties, such as anticancer, antibacterial, anti-inflammatory, and anti-psychotropic. Amongst the latter, N-thioalkyl carbazoles were proved to inhibit cancer cells damaging the nuclear DNA, through the inhibition of human topoisomerases. Herein, we report the design, synthesis and biological evaluation of nine new hybrid molecules in which NHC-Au(I) complexes and N-alkylthiolated carbazoles are linked together, in order to obtain novel biological multitarget agents. We demonstrated that the lead hybrid complexes possess anticancer, anti-inflammatory and antioxidant properties, with a high potential as useful tools for treating distinct aspects of several diseases, amongst them cancer.

Primed for Discovery

Antibiotics are essential components of current medical practice, but their effectiveness is being eroded by the increasing emergence of antimicrobial-resistant infections. At the same time, the rate of antibiotic discovery has slowed, and our future ability to treat infections is threatened. Among Christopher T. Walsh's many contributions to science was his early recognition of this threat and the potential of biosynthesis─genes and mechanisms─to contribute solutions. Here, we revisit a 2006 review by Walsh and co-workers that highlighted a major challenge in antibiotic natural product discovery: the daunting odds for identifying new naturally occurring antibiotics. The review described strategies to mitigate the odds challenge. These strategies have been used extensively by the natural product discovery community in the years since and have resulted in some promising discoveries. Despite these advances, the rarity of novel antibiotic natural products remains a barrier to discovery. We compare the challenge of discovering natural product antibiotics to the process of identifying new prime numbers, which are also challenging to find and an essential, if underappreciated, element of modern life. We propose that inclusion of filters for functional compounds early in the discovery pipeline is key to natural product antibiotic discovery, review some recent advances that enable this, and discuss some remaining challenges that need to be addressed to make antibiotic discovery sustainable in the future.

1,2,3‐Triazole‐Based New Aurones as Anticancer Agents with the Capability to Target Extracellular Digestive Enzymes

This study involves the synthesis of a series of dimethyl substituted novel aurones, featuring 1,2,3‐triazole as an integral structure. All the newly synthesized compounds were thoroughly characterized using various spectroscopic tools and also subjected to computational analysis utilizing the DFT/B3LYP methodology, which involved the determination of frontier molecular orbital energy values and the computation of various quantum chemical parameters. Further their impact on cell viability and cytotoxic activity on the adenocarcinoma gastric cell line (AGS) was investigated using cell‐based MTT assay. Compounds 6d, 6o and 6p displayed significant cytotoxic activity, reducing cell viability to a greater extent with IC50 values of 9.74, 20.09, and 5.92 µM, respectively and even better than the standard chemotherapeutic drug leucovorin (IC50 = 30.8 µM). In addition, all the compounds were also screened for their extracellular enzymatic assay and through in vitro results compound 6n emerged as the efficient inhibitor of amylase (% inhibition = 51.92) and trypsin (% inhibition = 68.36), whereas an activation is observed for lipase (% activation = 269.48). In silico molecular docking was also conducted to assess the interactions between proteins and ligands, revealing the binding patterns of the synthesized compounds and the standard drug with receptor proteins.

Novel tetrahydropyran-triazole hybrids with antiproliferative activity against human tumor cells

A series of new hybrid compounds was prepared combining tetrahydropyran rings with different aromatic systems by means of a 1,2,3-triazole, using a building block strategy. The design of these structures was guided by Lead-Likeness and Molecular Analysis (LLAMA) software, adding modifications to our most potent scaffold (the tetrahydropyran ring) to generate promising "lead-like" candidates, which were subsequently compared against reported anticancer compounds. Our synthesized compounds demonstrated significant antiproliferative activity when compared with the standards cisplatin and 5-fluorouracil, across a panel of six different tumor cell lines. Moreover, compared with our group's previous hybrid compounds, these new structures exhibit similar activity while offering simpler synthesis and greater potential for structural diversification, a fact that was previously an issue. Further investigations on the most active compounds included assessments of reproductive cell survival, inhibition of cell migration, and effects on nuclear morphology, indicating potential diverse mechanisms of action for these compounds. Pharmacokinetic properties were also calculated for the whole series of compounds using the pkCSM online software.

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.

Potent α-glucosidase inhibitors with benzimidazole-propionitrile hybridization; synthesis, bioassay and docking study

Background: Diabetes is characterized by a lack of insulin and insensitivity to insulin. In 2013, the global diabetes population was 382 million, with 90% of them having type 2 diabetes (non-insulin-dependent). It is predicted that this number will increase to 592 million by 2035.Aim: Here, we aimed to synthesize a series of benzimidazole-based derivatives B1-B32 with α-glucosidase inhibition potential as antidiabetic agents.Methods: Compounds B1-B32 were prepared in three three-step reactions, and the structures were elucidated using spectroscopic methods, namely 1H NMR, 13C NMR, MS and IR. Enzyme inhibition and kinetic study were done using commercial assay kits, and molecular docking study using autodock4.Results: Bioassay data showed that twenty-four out of the thirty-two tested compounds exhibited IC50 values ranging from 44 to 745 μM, surpassing the standard molecule, acarbose (IC50: 750 μM). it was determined that the best compound, B10, functions as a competitive inhibitor. Additionally, a molecular docking study provided insights into the interactions between the four most promising compounds (B5, B6, B10 and B28) and the active site residues within the enzyme.Conclusion: The tested compounds are interesting α-glucosidase inhibitors, which indicates the benefit of more bioassay studies, especially in vivo studies.

Multifunctional Molecular Hybrids Photoreleasing Nitric Oxide: Advantages, Pitfalls, and Opportunities

The multifaceted role nitric oxide (NO) plays in human physiology and pathophysiology has opened new scenarios in biomedicine by exploiting this free radical as an unconventional therapeutic against important diseases. The difficulties in handling gaseous NO and the strict dependence of the biological effects on its doses and location have made the light-activated NO precursors, namely NO photodonors (NOPDs), very appealing by virtue of their precise spatiotemporal control of NO delivery. The covalent integration of NOPDs and additional functional components within the same molecular skeleton through suitable linkers can lead to an intriguing class of multifunctional photoactivatable molecular hybrids. In this Perspective, we provide an overview of the recent advances in these molecular constructs, emphasizing those merging NO photorelease with targeting, fluorescent reporting, and phototherapeutic functionalities. We will highlight the rational design behind synthesizing these molecular hybrids and critically describe the advantages, drawbacks, and opportunities they offer in biomedical research.

Antibacterial and anti-biofilm activities of new fluoroquinolone derivatives coupled with nitrogen-based heterocycles

We report the design, synthesis, and antimicrobial evaluation of a series of ciprofloxacin (CP) conjugates coupled with nitrogen-containing heterocycles. In vitro screening of these new hybrid compounds (1-13) against a panel of planktonic bacterial strains highlighted thiazolyl homologs 6 and 7 as the most promising candidates for further investigation. These derivatives demonstrated potent growth-inhibitory activity against various standard and clinical isolates, with minimum inhibitory concentrations (MICs) ranging from 0.05 to 0.4 µg/ml, which are higher or comparable to the reference fluoroquinolone. Both compounds effectively inhibited biofilm formation by selected staphylococci across all tested concentrations (1-8 x MIC), displaying greater efficacy at higher doses compared to CP alone. Notably, conjugate 7 also significantly eradicated existing biofilms formed by S. aureus of various origin. Molecular docking studies revealed that conjugate 7 engages in a broader range of interactions with DNA gyrase and DNA topoisomerase IV than CP, suggesting stronger binding affinity and enhanced flexibility. This may contribute to its potential in overcoming bacterial resistance mechanisms. The above findings indicate compound 7 as a promising candidate for clinical development.

Dual Antibiotic Approach: Synthesis and Antibacterial Activity of Antibiotic-Antimicrobial Peptide Conjugates

In recent years, bacterial resistance to conventional antibiotics has become a major concern in the medical field. The global misuse of antibiotics in clinics, personal use, and agriculture has accelerated this resistance, making infections increasingly difficult to treat and rendering new antibiotics ineffective more quickly. Finding new antibiotics is challenging due to the complexity of bacterial mechanisms, high costs and low financial incentives for the development of new molecular scaffolds, and stringent regulatory requirements. Additionally, innovation has slowed, with many new antibiotics being modifications of existing drugs rather than entirely new classes. Antimicrobial peptides (AMPs) are a valid alternative to small-molecule antibiotics offering several advantages, including broad-spectrum activity and a lower likelihood of inducing resistance due to their multifaceted mechanisms of action. However, AMPs face challenges such as stability issues in physiological conditions, potential toxicity to human cells, high production costs, and difficulties in large-scale manufacturing. A reliable strategy to overcome the drawbacks associated with the use of small-molecule antibiotics and AMPs is combination therapy, namely the simultaneous co-administration of two or more antibiotics or the synthesis of covalently linked conjugates. This review aims to provide a comprehensive overview of the literature on the development of antibiotic-AMP conjugates, with a particular emphasis on critically analyzing the design and synthetic strategies employed in their creation. In addition to the synthesis, the review will also explore the reported antibacterial activity of these conjugates and, where available, examine any data concerning their cytotoxicity.

Design, synthesis, anticancer and in silico assessment of 8-caffeinyl chalcone hybrid conjugates

In this paper, we report the design, synthesis, and characterization of novel 8-caffeinyl chalcone hybrid conjugates, which were studied for their anticancer properties, toxicity, and in silico behavior. The synthesized compounds consist of 8-caffeinyl and chalcone structures with diverse substituents. The synthesis involved three main stages: bromination of caffeine to produce 8-BC, synthesis of chalcones, and subsequent coupling of these chalcones with 8-BC. The anticancer activity of the resulting compounds was evaluated in vitro against breast cancer MCF-7 and melanoma A-375 cell lines, revealing certain compounds to have significant efficacy compared to the reference drug methotrexate. Toxicity assessments using a healthy cell line indicated that most compounds displayed some level of toxicity, with only a few exceptions. Molecular docking studies indicated robust binding affinities of selected compounds to B-RAF kinase and hDHFR enzymes. In silico analyses of pharmacokinetic and physicochemical properties demonstrated that the majority of the compounds adhered to Lipinski's rule of five. Furthermore, density functional theory (DFT) studies were performed to gain deeper insights into the properties of the intermediates used throughout the research.

Copper-catalyzed aerobic annulation of hydrazones with dienones: an efficient route to pyrazole-linked hybrid molecules

A copper-catalyzed aerobic [3 + 2] annulation reaction to access various pyrazole-bound chalcones starting from readily available and cost-effective hydrazones and dienones is reported. These pyrazole-bound chalcones were further utilized effectively to prepare a series of pyrazole-linked hybrid molecules, such as pyrazole-pyrazoline, pyrazole-aziridine, and pyrazole-pyridine hybrids by efficient simple transformations. Synthetically challenging hybrid molecules were obtained in a simple, two-step process with high atom economy under aerobic copper catalysis.

Design, Synthesis, and Characterization of Novel Thiazolidine-2,4-Dione-Acridine Hybrids as Antitumor Agents

This study focuses on the synthesis and structural characterization of new compounds that integrate thiazolidine-2,4-dione, acridine moiety, and an acetamide linker, aiming to leverage the synergistic effects of these pharmacophores for enhanced therapeutic potential. The newly designed molecules were efficiently synthesized through a multi-step process and subsequently transformed into their hydrochloride salts. Comprehensive spectroscopic techniques, including nuclear magnetic resonance (NMR), high-resolution mass spectrometry (HRMS), infrared (IR) spectroscopy, and elemental analysis, were employed to determine the molecular structures of the synthesized compounds. Biological evaluations were conducted to assess the therapeutic potential of the new compounds. The influence of these derivatives on the metabolic activity of various cancer cell lines was assessed, with IC50 values determined via MTT assays. An in-depth analysis of the structure-activity relationship (SAR) revealed intriguing insights into their cytotoxic profiles. Compounds with electron-withdrawing groups generally exhibited lower IC50 values, indicating higher potency. The presence of the methoxy group at the linking phenyl ring modulated both the potency and selectivity of the compounds. The variation in the acridine core at the nitrogen atom of the thiazolidine-2,4-dione core significantly affects the activity against cancer cell lines, with the acridin-9-yl substituent enhancing the compounds' antiproliferative activity. Furthermore, compounds in their hydrochloride salt forms demonstrated better activity against cancer cell lines compared to their free base forms. Compounds 12c·2HCl (IC50 = 5.4 ± 2.4 μM), 13d (IC50 = 4.9 ± 2.9 μM), and 12f·2HCl (IC50 = 4.98 ± 2.9 μM) demonstrated excellent activity against the HCT116 cancer cell line, and compound 7d·2HCl (IC50 = 4.55 ± 0.35 μM) demonstrated excellent activity against the HeLa cancer cell line. Notably, only a few tested compounds, including 7e·2HCl (IC50 = 11.00 ± 2.2 μM), 7f (IC50 = 11.54 ± 2.06 μM), and 7f·2HCl (IC50 = 9.82 ± 1.92 μM), showed activity against pancreatic PATU cells. This type of cancer has a very high mortality due to asymptomatic early stages, the occurrence of metastases, and frequent resistance to chemotherapy. Four derivatives, namely, 7e·2HCl, 12d·2HCl, 13c·HCl, and 13d, were tested for their interaction properties with BSA using fluorescence spectroscopic studies. The values for the quenching constant (Ksv) ranged from 9.59 × 104 to 10.74 × 104 M-1, indicating a good affinity to the BSA protein.

Recent Advances in the Development of Hybrid Drugs

In the search for innovative, selective, effective, and safer treatment strategies, hybrid drugs have gained worldwide momentum [...].

Bipyraloxifene - a modified raloxifene vector against triple-negative breast cancer

Raloxifene, a selective oestrogen receptor modulator (SERM), has demonstrated efficacy in the prevention and therapy of oestrogen receptor-positive (ER+) breast cancer, with some degree of effectiveness against triple-negative forms. This suggests the presence of oestrogen receptor-independent pathways in raloxifene-mediated anticancer activity. To enhance the potential of raloxifene against the most aggressive breast cancer cells, hybrid molecules combining the drug with a metal chelator moiety have been developed. In this study, we synthetically modified the structure of raloxifene by incorporating a 2,2'-bipyridine (2,2'-bipy) moiety, resulting in [6-methoxy-2-(4-hydroxyphenyl)benzo[b]thiophen-3-yl]-[4-(2,2'-bipyridin-4'-yl-methoxy)phenyl]methanone (bipyraloxifene). We investigated the cytotoxic activity of both raloxifene and bipyraloxifene against ER+ breast adenocarcinomas, glioblastomas, and a triple-negative breast cancer (TNBC) cell line, elucidating their mode of action against TNBC. Bipyraloxifene maintained a mechanism based on caspase-mediated apoptosis but exhibited significantly higher activity and selectivity compared to the original drug, particularly evident in triple-negative stem-like MDA-MB-231 cells.

Construction of 5-Fluorouracil and Gallium Corrole Conjugates for Enhanced Photodynamic Therapy

Molecular hybridization is a well-established strategy for developing new drugs. In the pursuit of promising photosensitizers (PSs) with enhanced photodynamic therapy (PDT) efficiency, a series of novel 5-fluorouracil (5FU) gallium corrole conjugates (1-Ga-4-Ga) were designed and synthesized by hybridizing a chemotherapeutic drug and PSs. Their photodynamic antitumor activity was also evaluated. The most active complex (2-Ga) possesses a low IC50 value of 0.185 μM and a phototoxic index of 541 against HepG2 cells. Additionally, the 5FU-gallium corrole conjugate (2-Ga) exhibited a synergistic increase in cytotoxicity under irradiation. Excitedly, treatment of HepG2 tumor-bearing mice with 2-Ga under irradiation could completely ablate tumors without harming normal tissues. 2-Ga-mediated PDT could disrupt mitochondrial function, cause cell cycle arrest in the sub-G1 phase, and activate the cell apoptosis pathway by upregulating the cleaved PARP expression and the Bax/Bcl-2 ratios. This work provides a useful strategy for the design of new corrole-based chemo-photodynamic therapy drugs.

Novel hybrid thiazoles, bis-thiazoles linked to azo-sulfamethoxazole: Synthesis, docking, and antimicrobial activity

The reaction of sulfamethoxazolehydrazonoyl chloride with thiosemicarbazones, bis-thiosemicarbazones, or 4-amino-3-mercapto-1,2,4-triazole in dioxane in the presence of triethylamine as a basic catalyst at reflux resulted in the regioselective synthesis of thiazoles and bis-thiazoles linked to azo-sulfamethoxazole as novel hybrid molecules. The structures of the new compounds were confirmed using a range of spectra. Each compound's antibacterial properties were evaluated using the agar well-diffusion technique, and most of them demonstrated significant potency. In silico investigations revealed that the described compounds had strong interactions with the binding sites of MurE ligase, tyrosyl-tRNA synthetase, and dihydropteroate synthase, demonstrating inhibitory activity.

Carvacrol and Thymol Hybrids: Potential Anticancer and Antibacterial Therapeutics

Cancer is ranked among lethal diseases globally, and the increasing number of cancer cases and deaths results from limited access to effective therapeutics. The use of plant-based medicine has been gaining interest from several researchers. Carvacrol and its isomeric compound, thymol, are plant-based extracts that possess several biological activities, such as antimalarial, anticancer, antifungal, and antibacterial. However, their efficacy is compromised by their poor bioavailability. Thus, medicinal scientists have explored the synthesis of hybrid compounds containing their pharmacophores to enhance their therapeutic efficacy and improve their bioavailability. Hence, this review is a comprehensive report on hybrid compounds containing carvacrol and its isomer, thymol, with potent anticancer and antibacterial agents reported between 2020 and 2024. Furthermore, their structural activity relationship (SAR) and recommended future strategies to further enhance their therapeutic effects will be discussed.

Novel hybrid compounds of sclareol and doxorubicin as potential anticancer nanotherapy for glioblastoma

Two novel hybrid compounds, CON1 and CON2, have been developed by combining sclareol (SC) and doxorubicin (DOX) into a single molecular entity. These hybrid compounds have a 1:1 molar ratio of covalently linked SC and DOX. They have demonstrated promising anticancer properties, especially in glioblastoma cells, and have also shown potential in treating multidrug-resistant (MDR) cancer cells that express the P-glycoprotein (P-gp) membrane transporter. CON1 and CON2 form nanoparticles, as confirmed by Zetasizer, transmission electron microscopy (TEM), and chemical modeling. TEM also showed that CON1 and CON2 can be found in glioblastoma cells, specifically in the cytoplasm, different organelles, nucleus, and nucleolus. To examine the anticancer properties, the U87 glioblastoma cell line, and its corresponding multidrug-resistant U87-TxR cell line, as well as patient-derived astrocytoma grade 3 cells (ASC), were used, while normal human lung fibroblasts were used to determine the selectivity. CON1 and CON2 exhibited better resistance and selectivity profiles than DOX, showing less cytotoxicity, as evidenced by real-time cell analysis, DNA damage determination, cell death induction, mitochondrial respiration, and mitochondrial membrane depolarization studies. Cell cycle analysis and the β-galactosidase activity assay suggested that glioblastoma cells die by senescence following CON1 treatment. Overall, CON1 and CON2 showed great potential as they have better anticancer features than DOX. They are promising candidates for additional preclinical and clinical studies on glioblastoma.

Molecular Docking, Synthesis, and Characterization of Furanyl-Pyrazolyl Acetamide and 2,4-Thiazolidinyl-Furan-3-Carboxamide Derivatives as Neuroinflammatory Protective Agents

Microglia are key immune cells in the brain that maintain homeostasis and defend against immune threats. Targeting the dysfunctional microglia is one of the most promising approaches to inhibit neuroinflammation. In the current study, a diverse series of molecular hybrids were designed and screened through molecular docking against two neuroinflammatory targets, namely HMGB1 (2LY4) and HMGB1 Box A (4QR9) proteins. Based on the outcomes of docking scores fifteen compounds; ten furanyl-pyrazolyl acetamides 11(a-j), and five 2,4-thiazolidinyl-furan-3-carboxamide 15(a-e) derivatives were selected for further synthesis, followed by biological evaluation. The selected compounds, 11(a-j) and 15(a-e) were successfully synthesized with moderate to good yields, and structures were confirmed by IR, NMR, and mass spectra. The in-vitro cytotoxicity was evaluated on microglial cells namely BV-2, N-9, HMO6, leukemic HAP1, and human fibroblast cells. Further western-blot analysis revealed that 11h, 11f, 11c, 11j, 15d, 15c, 15e, and 15b compounds significantly suppressed anti-inflammatory markers such as TNF-α, IL-1, IL-6, and Bcl-2. All derivatives were moderate in potency compared to reference doxorubicin and could potentially act as novel anti-neuroinflammatory agents. This study can act as a beacon for further research in the application of furan-pyrazole and furan-2,4-thiazolidinediones as lead moieties for anti-neuroinflammatory and related diseases.

Potentials and future perspectives of multi-target drugs in cancer treatment: the next generation anti-cancer agents

Cancer is a major public health problem worldwide with more than an estimated 19.3 million new cases in 2020. The occurrence rises dramatically with age, and the overall risk accumulation is combined with the tendency for cellular repair mechanisms to be less effective in older individuals. Conventional cancer treatments, such as radiotherapy, surgery, and chemotherapy, have been used for decades to combat cancer. However, the emergence of novel fields of cancer research has led to the exploration of innovative treatment approaches focused on immunotherapy, epigenetic therapy, targeted therapy, multi-omics, and also multi-target therapy. The hypothesis was based on that drugs designed to act against individual targets cannot usually battle multigenic diseases like cancer. Multi-target therapies, either in combination or sequential order, have been recommended to combat acquired and intrinsic resistance to anti-cancer treatments. Several studies focused on multi-targeting treatments due to their advantages include; overcoming clonal heterogeneity, lower risk of multi-drug resistance (MDR), decreased drug toxicity, and thereby lower side effects. In this study, we'll discuss about multi-target drugs, their benefits in improving cancer treatments, and recent advances in the field of multi-targeted drugs. Also, we will study the research that performed clinical trials using multi-target therapeutic agents for cancer treatment.

Hybrid pharmacophore design and synthesis of donepezil-inspired aurone derivative salts as multifunctional acetylcholinesterase inhibitors

Flavonoids, a ubiquitous group of plant polyphenols, are well-known for their beneficial effects on human health. Their phenylchromane skeletons have structural similarities to donepezil [the US FDA-approved drug used to treat Alzheimer's disease (AD)]. The objective of this study was to design and synthesize valuable agents derived from flavonoids for relieving the symptoms of AD. A variety of flavonoid derivative salts incorporating benzylpyridinium units were synthesized and several of them remarkedly inhibited acetylcholinesterase (AChE) activity in vitro. Additionally, aurone derivative salts protected against cell death resulting from t-BHP exposure in rat pheochromocytoma PC12 cells and slightly promoted neurite outgrowth. Furthermore, they potently suppressed the aggregation of amyloid-β (Aβ1-42). Our findings highlight the effectiveness of donepezil-inspired aurone derivative salts as multipotent candidates for AD.

Exploring acetaminophen prodrugs and hybrids: a review

This critical review highlights the advances in developing new molecules for treating pain syndrome, an important issue for human health. Acetaminophen (APAP, known as paracetamol) and nonsteroidal anti-inflammatory drugs (NSAIDs) are commonly used in clinical practice despite their adverse effects. Research is being conducted to develop innovative drugs with improved pharmaceutical properties to mitigate these effects. A more practical way to achieve that is to study well-known and time-tested drugs in their molecular combinations. Accordingly, the present work explores APAP and their combined chemical entities, i.e., prodrugs (soft drugs), codrugs (mutual prodrugs), and hybrids. Due to their molecular structure, APAP prodrugs or codrugs could be considered merged or conjugated hybrids; all these names are very fluid terms. This article proposed a structural classification of these entities to better analyze their advances. So, the following: carrier-linked O-modified APAP, -linked N-modified APAP derivatives (prodrugs), and direct- and spacer-N,O-linked APAP hybrids (codrugs) are the central parts of this review and are examined, especially ester and amide NSAID-APAP molecules. The C-linked APAP and nitric oxide (NO)-releasing APAP hybrids were also briefly discussed. Prime examples of APAP-based drugs such as propacetamol, benorylate, acetaminosalol, nitroparacetamol, and agent JNJ-10450232 weave well into this classification. The proposed classification is the first and original, giving a better understanding of the SAR studies for new pain relievers research and the design development for the analgesic APAP-(or NSAID)-based compounds.

Hybrid Heterocycles: Ag(I)-Catalyzed C-C/C-N/C-O Coupled Cascade Dual Cyclization to Valuable Indolo-4H-indolones and Indolo-4H-chromenes

Herein, we report a highly efficient Ag(I)-catalyzed indolyzation with Friedel-Crafts alkylation through a cascade cyclization strategy for accessing valuable hybrid heterocycles for the first time. This general strategy consists of forming four C-C/C-N/C-O bonds toward dual annulation reactions of 2-alkynylanilines with methyl benzoate-2-carboxaldehydes and aromatic amines, as well as with salicylaldehydes and malononitrile. Variably substituted new indolo-4H-phthalimidines and indolo-4H-chromenes were synthesized with excellent yields (85-93%) under mild reaction conditions.

Synthesis of Novel Diphenyl Ether-Based Bis-Heterocycles as Novel Hybrid Molecules via Michael and Other Cyclocondensation Reactions

Molecular hybridization is a technique used in drug creation that involves combining the pharmacophoric moieties of multiple bioactive compounds to create a new hybrid molecule with better affinity and effectiveness. In this regard, we created unique hybrid molecules out of diphenyl ether-linked fused pyrans and other heterocycles. The Michael reaction of 4,4'-oxydibenzaldehyde with malononitrile and various active methylene derivatives, as well as enaminone derivatives, produced the matching bis-fused pyrans and fused pyridines, both connected to a diphenyl ether moiety. Furthermore, the acid-catalyzed reaction of 4,4'-oxydibenzaldehyde with dimedone or β-naphthol produced the corresponding new bis(hexahydro-1H-xanthene-1,8-dione) and bis(14H-dibenzo[a,j]xanthene). The processes by which the target products are formed were also examined.

Effect of Hydroxytyrosol Derivatives of Donepezil on the Activity of Enzymes Involved in Neurodegenerative Diseases and Oxidative Damage

Monoamine oxidase and xanthine oxidase inhibitors represent useful multi-target drugs for the prevention, attenuation, and treatment of oxidative damage and neurodegenerative disorders. Chimeric molecules, constituted by naturally derived compounds linked to drugs, represent lead compounds to be explored for the discovery of new synthetic drugs acting as enzyme inhibitors. We have previously reported that seven hydroxytyrosol-donepezil hybrid compounds play a protective role in an in vitro neuronal cell model of Alzheimer's disease. In this work, we analyzed the effects exerted by the hybrid compounds on the activity of monoamine oxidase A (MAO-A) and B (MAO-B), as well as on xanthine oxidase (XO), enzymes involved in both neurodegenerative disorders and oxidative stress. The results pointed to the identification, among the compounds tested, of selective inhibitors between the two classes of enzymes. While the 4-hydroxy-3-methoxyphenethyl 1-benzylpiperidine-4-carboxylate- (HT3) and the 4-hydroxyphenethyl 1-benzylpiperidine-4-carboxylate- donepezil derivatives (HT4) represented the best inhibitors of MAO-A, with a scarce effect on MAO-B, they were almost ineffective on XO. On the other hand, the 4,5-dihydroxy-2-nitrophenethyl 1-benzylpiperidine-4-carboxylate donepezil derivative (HT2), the least efficient MAO inhibitor, acted like the best XO inhibitor. Therefore, the differential enzymatic targets identified among the hybrid compounds synthesized enhance the possible applications of these polyphenol-donepezil hybrids in neurodegenerative disorders and oxidative stress.

Multifunctional Cationic Hyperbranched Polyaminoglycosides that Target Multiple Mediators for Severe Abdominal Trauma Management

Trauma and its associated complications, including dysregulated inflammatory responses, severe infection, and disseminated intravascular coagulation (DIC), continue to pose lethal threats worldwide. Following injury, cell-free nucleic acids (cfNAs), categorized as damage-associated molecular patterns (DAMPs), are released from dying or dead cells, triggering local and systemic inflammatory responses and coagulation abnormalities that worsen disease progression. Harnessing cfNA scavenging strategies with biomaterials has emerged as a promising approach for treating posttrauma systemic inflammation. In this study, the effectiveness of cationic hyperbranched polyaminoglycosides derived from tobramycin (HPT) and disulfide-included HPT (ss-HPT) in scavenging cfNAs to mitigate posttrauma inflammation and hypercoagulation is investigated. Both cationic polymers demonstrate the ability to suppress DAMP-induced toll-like receptor (TLR) activation, inflammatory cytokine secretion, and hypercoagulation by efficiently scavenging cfNAs. Additionally, HPT and ss-HPT exhibit potent antibacterial efficacy attributed to the presence of tobramycin in their chemical composition. Furthermore, HPT and ss-HPT exhibit favorable modulatory effects on inflammation and therapeutic outcomes in a cecal ligation puncture (CLP) mouse abdominal trauma model. Notably, in vivo studies reveal that ss-HPT displayed high accumulation and retention in injured organs of traumatized mice while maintaining a higher biodegradation rate in healthy mice, contrasting with findings for HPT. Thus, functionalized ss-HPT, a bioreducible polyaminoglycoside, holds promise as an effective option to enhance therapeutic outcomes for trauma patients by alleviating posttrauma inflammation and coagulation complications.

Ciprofloxacin and Norfloxacin Hybrid Compounds: Potential Anticancer Agents

BACKGROUND

The concept of utilizing drug repurposing/repositioning in the development of hybrid molecules is an important strategy in drug discovery. Fluoroquinolones, a class of antibiotics, have been reported to exhibit anticancer activities. Although anticancer drug development is achieving some positive outcomes, there is still a need to develop new and effective anticancer drugs. Some limitations associated with most of the available anticancer drugs are drug resistance and toxicity, poor bio-distribution, poor solubility, and lack of specificity, thereby reducing their therapeutic outcomes.

OBJECTIVES

Fluoroquinolones, a known class of antibiotics, have been explored by hybridizing them with other pharmacophores and evaluating their anticancer activity in silico and in vitro. Hence, this review provides an update on new anticancer drugs containing fluoroquinolones moiety, Ciprofloxacin and Norfloxacin between 2020 and 2023, their structural relationship activity, and the future strategies to develop potent chemotherapeutic agents.

METHODS

Fluoroquinolones were mostly hybridized via the N-4 of the piperazine ring on position C-7 with known pharmacophores characterized, followed by biological studies to evaluate their anticancer activity.

RESULTS

The hybrid molecules displayed promising and interesting anticancer activities. Factors such as the nature of the linker, the presence of electron-withdrawing groups, nature, and position of the substituents influenced the anticancer activity of the synthesized compounds.

CONCLUSION

The hybrids were selective towards some cancer cells. However, further in vivo studies are needed to fully understand their mode of action.

Novel 8-Methoxycoumarin-3-Carboxamides with potent anticancer activity against liver cancer via targeting caspase-3/7 and β-tubulin polymerization

In the present study, we explored the potential of coumarin-based compounds, known for their potent anticancer properties, by designing and synthesizing a novel category of 8-methoxycoumarin-3-carboxamides. Our aim was to investigate their antiproliferative activity against liver cancer cells. Toward this, we developed a versatile synthetic approach to produce a series of 8-methoxycoumarin-3-carboxamide analogues with meticulous structural features. Assessment of their antiproliferative activity demonstrated their significant inhibitory effects on the growth of HepG2 cells, a widely studied liver cancer cell line. Among screened compounds, compound 5 exhibited the most potent antiproliferative activity among the screened compounds (IC50 = 0.9 µM), outperforming the anticancer drug staurosporine (IC50 = 8.4 µM), while showing minimal impact on normal cells. The flow cytometric analysis revealed that compound 5 induces cell cycle arrest during the G1/S phase and triggers apoptosis in HepG2 cells by increasing the percentage of cells arrested in the G2/M and pre-G1 phases. Annexin V-FITC/PI screening further supported the induction of apoptosis without significant necrosis. Further, compound 5 exhibited the ability to activate caspase3/7 protein and substantially inhibited β-tubulin polymerization activity in HepG2 cells. Finally, molecular modelling analysis further affirmed the high binding affinity of compound 5 toward the active cavity of β-tubulin protein, suggesting its mechanistic involvement. Collectively, our findings highlight the therapeutic potential of the presented class of coumarin analogues, especially compound 5, as promising candidates for the development of effective anti-hepatocellular carcinoma agents.

Design, synthesis, anti-inflammatory evaluation, and molecular modelling of new coumarin-based analogs combined curcumin and other heterocycles as potential TNF-α production inhibitors via upregulating Nrf2/HO-1, downregulating AKT/mTOR signalling pathways and downregulating NF-κB in LPS induced macrophages

Persistent inflammation contributes to various inflammatory conditions. Inflammation-related diseases may be treated by inhibiting pro-inflammatory mediators and cytokines. Curcumin and coumarin derivatives can target signalling pathways and cellular factors to address immune-related and inflammatory ailments. This study involved designing and synthesising three series of coumarin-based analogs that incorporated curcumin and other heterocycles. These analogs were evaluated for their potential as anti-inflammatory agents in LPS-induced macrophages. Among the fourteen synthesised coumarin derivatives, compound 14b, which contained 3,4-dimethoxybenzylidene hydrazinyl, demonstrated the highest anti-inflammatory activity with an EC50 value of 5.32 μM. The anti-inflammatory effects of 14b were achieved by modulating signalling pathways like AKT/mTOR and Nrf2/HO-1, and downregulating NF-kβ, resulting in reduced production of pro-inflammatory cytokines such as IL-6, IL-1β, and TNF-α. The modelling studies revealed that 14b and dexamethasone bind to the same TNF-α pocket, suggesting that 14b has potential as a therapeutic agent superior to dexamethasone for TNF-α.

Novel Scaffolds Based on Bis-thiazole Connected to Quinoxaline or Thienothiophene through 2-Phenoxy-N-arylacetamide Groups as New Hybrid Molecules: Synthesis, Antibacterial Activity, and Molecular Docking Investigations

The resistance of microorganisms to antimicrobials has endangered the health of many people across the world. Overcoming the resistance problem will require the invention of molecules with a new mechanism of action so that no cross-resistance with existing therapies occurs. Because of their powerful antibacterial activity against a wide spectrum of Gram-positive and Gram-negative bacterial strains, heterocyclic compounds are appealing candidates for medicinal chemists. In this regard, as unique hybrid compounds, we synthesized a novel family of bis-thiazoles linked to quinoxaline or thienothiophene via the 2-phenoxy-N-arylacetamide moiety. The target compounds were synthesized by reacting the relevant bis(α-haloketones) with the corresponding thiosemicarbazones in EtOH at reflux with a few drops of TEA. Under comparable reaction conditions, the isomeric bis(thiazoles) were synthesized by reacting the appropriate bis(thiosemicarbazone) with the respective α-haloketones. The structures of the novel compounds were confirmed using elements and spectral data. All of the synthesized compounds were tested for antibacterial activity in vitro. With an inhibitory zone width of 12 mm, compound 12a had the same activity as the reference medication tobramycin against Staphylococcus aureus. Compound 12b showed 20 mg/mL as a minimum inhibitory concentration (MIC) against Bacillus subtilis. Some of the synthesized compounds were tested via molecular docking against two bacterial proteins (dihydrofolate reductase and tyrosyl-tRNA synthetase).

Silver-Catalyzed Cascade Radical Bicyclization Reaction: An Atom- and Step-Economical Strategy Accessing γ-Lactam Containing Isoquinolinediones

An efficient and convenient method for the cascade radical bicyclization of N-phenyl-4-pentenamides with N-methyl-N-methacryloylbenzamides under silver-catalyzed conditions is described. Based on this newly developed strategy, a variety of valuable γ-lactam containing isoquinolinediones can be effectively synthesized in one step within 0.5 h, during which two C-C bonds, one C-N bond, and two new N-heterocycles were formed concurrently. With N-aryl allyl carbamates, similar 2-oxazolidinone substituted isoquinolinedione compounds can likewise be produced. The approach demonstrates wide functional group compatibility, high step- and atom-economy, and the ability to be scaled up to gram quantities in a satisfactory yield. It marks the first instance of introducing γ-lactams into isoquinoline-1,3(2H,4H)-diones to construct linked hybrid drug-like molecules, thereby making this strategy highly attractive to drug discovery.

Chlorambucil-Bearing Hybrid Molecules in the Development of Potential Anticancer Agents

Increasing cases of cancer have been a primary concern in recent decades. Developing new chemotherapeutics is challenging and has been faced with limitations, such as multidrug resistance, poor specificity, selectivity, and toxicity. The aforementioned factors contribute to treatment failure. Hybrid compounds have features that can overcome the limitations mentioned above. Chlorambucil, an anticancer drug that is used to treat prostate and breast cancer, suffers from poor aqueous solubility and specificity, a short half-life, and severe side effects, including anaemia and bone marrow suppression. It compromises the immune system, resulting in treatment failure. Hence, its combination with other pharmacophores has been reported to result in effective anticancer agents with fewer side effects and high therapeutic outcomes. Furthermore, this review gives an update (2010 to date) on the developments of chlorambucil hybrid compounds with anticancer activity, and the structure-activity relationship (SAR), and also highlights future strategies for developing novel anticancer agents.

Novel Thiazolidine-2,4-dione-trimethoxybenzene-thiazole Hybrids as Human Topoisomerases Inhibitors

Cancer is a complex and heterogeneous disease and is still one of the leading causes of morbidity and mortality worldwide, mostly as the population ages. Despite the encouraging advances made over the years in chemotherapy, the development of new compounds for cancer treatments is an urgent priority. In recent years, the design and chemical synthesis of several innovative hybrid molecules, which bring different pharmacophores on the same scaffold, have attracted the interest of many researchers. Following this strategy, we designed and synthetized a series of new hybrid compounds that contain three pharmacophores, namely trimethoxybenzene, thiazolidinedione and thiazole, and tested their anticancer properties on two breast cancer (MCF-7 and MDA-MB-231) cell lines and one melanoma (A2058) cell line. The most active compounds were particularly effective against the MCF-7 cells and did not affect the viability of the normal MCF-10A cells. Docking simulations indicated the human Topoisomerases I and II (hTopos I and II) as possible targets of these compounds, the inhibitory activity of which was demonstrated by the mean of direct enzymatic assays. Particularly, compound 7e was proved to inhibit both the hTopo I and II, whereas compounds 7c,d blocked only the hTopo II. Finally, compound 7e was responsible for MCF-7 cell death by apoptosis. The reported results are promising for the further design and synthesis of other analogues potentially active as anticancer tools.

Evaluation of Antimicrobial Activities against Various E. coli Strains of a Novel Hybrid Peptide-LENART01

Finding the ideal antimicrobial drug with improved efficacy and a safety profile that eliminates antibiotic resistance caused by pathogens remains a difficult task. Indeed, there is an urgent need for innovation in the design and development of a microbial inhibitor. Given that many promising antimicrobial peptides with excellent broad-spectrum antibacterial properties are secreted by some frog species (e.g., bombesins, opioids, temporins, etc.), our goal was to identify the antimicrobial properties of amphibian-derived dermorphin and ranatensin peptides, which were combined to produce a hybrid compound. This new chimera (named LENART01) was tested for its antimicrobial activity against E. coli strains K12 and R1-R4, which are characterized by differences in lipopolysaccharide (LPS) core oligosaccharide structure. The results showed that LENART01 had superior activity against the R2 and R4 strains compared with the effects of the clinically available antibiotics ciprofloxacin or bleomycin (MIC values). Importantly, the inhibitory effect was not concentration dependent; however, LENART01 showed a time- and dose-dependent hemolytic effect in hemolytic assays.

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.

Divergent synthesis of two types of indolizines from pyridine-2-acetonitrile, (hetero)arylglyoxal, and TMSCN

Herein we describe the divergent synthesis of two types of indolizines via construction of the pyrrole moiety from pyridine-2-acetonitriles, arylglyoxals, and TMSCN. While one-pot three-component coupling provided 2-aryl-3-aminoindolizines via an unusual fragmentation process, a sequential two-step assembly protocol with these starting materials allowed efficient access to a wide range of new 2-acyl-3-aminoindolizines through an aldol condensation-Michael addition-cycloisomerization process. The subsequent manipulation of 2-acyl-3-aminoindolizines enabled direct access to novel polycyclic N-fused heteroaromatic skeletons.

Synergistic or antagonistic antioxidant combinations - a case study exploring flavonoid-nitroxide hybrids

Neurodegenerative diseases impose a considerable medical and public health burden on populations throughout the world. Oxidative stress, an imbalance in pro-oxidant/antioxidant homeostasis that leads to the generation of reactive oxygen species (ROS), has been implicated in the progression of a number of neurodegenerative diseases. The manipulation of ROS levels may represent a promising treatment option to slow down neurodegeneration, although adequate potency of treatments has not yet been achieved. Using a hybrid pharmacology approach, free radical nitroxide antioxidants were hybridised with a class of natural antioxidants, flavonoids, to form a potential multitargeted antioxidant. Modification of the Baker-Venkataraman reaction achieved the flavonoid-nitroxide hybrids (6-9) in modest yields. Antioxidant evaluation of the hybrids by cyclic voltammetry showed both redox functionalities were still active, with little influence on oxidation potential. Assessment of the peroxyl radical scavenging ability through an ORAC assay showed reduced antioxidant activity of the hybrids compared to their individual components. It was hypothesized that the presence of the phenol in the hybrids creates a more acidic medium which does not favour regeneration of the nitroxide from the corresponding oxammonium cation, disturbing the typical catalytic cycle of peroxyl radical scavenging by nitroxides. This work highlights the potential intricacies involved with drug hybridization as a strategy for new therapeutic development.