Hybrid molecules with a dual mode of action: dream or reality?

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

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

In silico molecular modeling and in vitro biological screening of novel benzimidazole-based piperazine derivatives as potential acetylcholinesterase and butyrylcholinesterase inhibitors

New series of benzimidazole incorporating piperazine moieties in single molecular framework has been reported. The structures of the synthesized derivatives were assigned by 1H-NMR, 13C-NMR, and HR-MS techniques. The hybrid derivatives were evaluated for their acetylcholinesterase and butyrylcholinesterase inhibition effect. All the synthesized analogs showed good to moderate inhibitory effect ranging from IC50 value 0.20 ± 0.01 µM to 0.50 ± 0.10 µM for acetylcholinesterase and from IC50 value 0.25 ± 0.01 µM to 0.70 ± 0.10 µM for butyrylcholinesterase except one that showed least potency with IC50 value 1.05 ± 0.1 µM and 1.20 ± 0.1 µM. The differences in inhibitory potential of synthesized compounds were due to the nature and position of substitution attached to the main ring. Additionally, molecular docking study was carried out for most active in order to explore the binding interactions established by ligand (active compounds) with the active residues of targeted AChE & BuChE enzyme.

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.

Novel coumarin-piperazine-2(5H)-furanone hybrids as potential anti-lung cancer agents: Synthesis, biological evaluation and molecular docking studies

Novel coumarin-piperazine-2(5H)-furanone hybrids 5a-l were efficiently synthesized by introducing a furanone scaffold into coumarin using piperazine as a linker. The cytotoxicity of all hybrids 5a-l were evaluated by MTT assay on human lung cancer A549 cells and normal human lung fibroblast WI-38 cells with cytarabine (CAR) as a positive control. Hybrid 5l (IC50 = 11.28 μM) was the most toxic to A549 cells, 18-fold more toxic than the reference CAR (IC50 = 202.57 μM). Moreover, hybrid 5l (IC50 = 411.93 μM) was less toxic to WI-38 cells, with a much higher selectivity (5l, SI ≈ 37, WI-38/A549) than CAR (SI ≈ 2). Structure-activity relationship analysis showed that both the cytotoxicity against A549 cells and selectivity (WI-38/A549) were greatly improved when the bornyl group was incorporated in the hybrids (5c, 5f, 5i and 5l). Further, hybrid 5l was more toxic and selective against four types of human lung cancer cells (A549, Calu-1, PC-9 and H460; IC50 = 5.72-45.46 μM; SI ≈ 9-72) than three other types of human cancer cells (SK-BR-3, 786-O and SK-OV-3, IC50 = 39.07-130.82 μM; SI ≈ 0-2), showing remarkable specificity. In particular, hybrid 5l (IC50 = 5.72 μM) showed the highest cytotoxicity against H460 cells with the highest selectivity of up to 72 (WI-38/H460). Flow cytometric analysis showed that hybrid 5l induced apoptosis in H460 cells in a concentration-dependent manner. Molecular docking studies revealed a high binding affinity of hybrid 5l with CDK2 protein. Hybrid 5l is expected to be a leading candidate for anti-lung cancer agents.

Antimalarial and antioxidant activities of novel artesunate-ellagic acid hybrid compound in vitro and in vivo

Introduction: Emergence of drug resistant strains of Plasmodium species has necessitated the search for novel antimalarials with unique mechanisms of action. Synthesis of hybrid compounds has been one approach to tackling this challenge. In this study, the synthesis of artesunate-ellagic acid hybrid compound (EA31) from ellagic acid and artesunate and its evaluation for antimalarial and antioxidant activities using in vitro and in vivo models were carried out. Method: EA31 was synthesized from artesunate and ellagic acid. The activities of the hybrid compound against Plasmodium falciparum W2 and P. berghei NK65 were evaluated, and its antioxidant activities were also determined. Results: The results revealed that EA31 was more active against P. falciparum W2 (chloroquine resistant) clone and less cytotoxic to buffalo green monkey kidney cell line compared to artesunate. EA31 was also active against Plasmodium berghei NK65 in vivo. The results revealed inhibition of β-hematin formation as one of the mechanisms of action of EA31. EA31 also exhibited antioxidant activities. Conclusion: The results revealed that EA31 may exert dual action of killing malaria parasite and mopping the reactive oxygen species that mediate the secondary complications of malaria.

Synthesis, Biological Properties, and Molecular Docking Study of Novel 1,2,3-Triazole-8-quinolinol Hybrids

A new series of 1,2,3-triazole-8-quinolinol hybrids were synthesized in good yields using monosubstituted acetonitriles and 5-azidomethyl-8-quinolinol as the starting reagents via a one-step protocol. The structures of 1,2,3-triazole-8-quinolinol hybrids were characterized by nuclear magnetic resonance (1H and 13C NMR) spectroscopy and elemental analysis. Antibacterial activity in vitro of all the synthesized hybrids was investigated against Escherichia coli (E. coli), Xanthomonas fragariae (X. fragariae), Staphylococcus aureus (S. aureus), and Bacillus subtilis (B. subtilis) applying the methods of disk diffusion and minimal inhibition concentration (MIC). Hybrid 7 exhibited excellent antibacterial capacity, with an MIC value of 10 μg/mL against S. aureus and 20 μg/mL against B. subtilis, E. coli, and X. fragariae, which were comparable to those that of the standard antibiotic nitroxoline. A structure-activity relationship (SAR) study of 1,2,3-triazole-8-quinolinol hybrids showed that introducing electron-donating substituents in the 1,2,3-triazole ring at the 4-position is important for activity. Quantum chemical calculations have been undertaken to employ the Gaussian software in the B3LYP, HF, and M062X basis sets using 3-21g, 6-31g, and SDD levels to further explain linkages within the antibacterial findings. Furthermore, molecular docking investigations were also conducted to investigate the binding affinities as well as the interactions of some hybrids with the target proteins. An absorption, distribution, metabolism, excretion, and toxicity (ADME/T) investigation was carried out to scrutinize the viability of employing the 1,2,3-triazole-8-quinolinol hybrids as medicines.

Pseudo-Natural Products: Expanding chemical and biological space by surpassing natural constraints

This review explores the recent advancements in the design and synthesis of pseudo-natural products (pseudo-NPs) by employing innovative principles and strategies, heralding a transformative era in chemistry and biology. Pseudo-NPs, produced through in silico fragmentation and the de novo recombination of natural product fragments, reveal compounds endowed with distinct biological activities. Their advantage lies in transcending natural product structures, fostering diverse possibilities. Research in this area over the past decade has yielded unconventional combinations of natural product fragments, leading to the identification of novel compounds possessing unique scaffolds and biological significance, thereby contributing to the discovery of new therapeutics. The pseudo-NPs exert potent biological effects through various signaling pathways. In chemical biology and medicinal chemistry, designing pseudo-NPs is an important strategy, harnessing molecular hybridization and bioinspired synthesis to generate diverse compounds with remarkable biological activities, underscoring their immense potential in drug discovery and development.

In vitro and in vivo antiplasmodial activity of a synthetic dihydroartemisinin-eosin B hybrid

With the inexorable prevalence and spread of drug-resistant malaria strains, many efforts have been made to find alternative chemotherapeutic agents. In this regard, scientists have developed the concept of hybridization of two or more active pharmacophores into a single chemical compound, resulting in "antimalarial hybrids." The aim of this study was planned based on the highly synergistic effect of the physical hybrid of dihydroartemisinin (DHA) with eosin B (EB). Therefore, a chemical hybrid of the two compounds (DHA-EB) was synthesized, and its antimalarial activity was investigated in vitro and in vivo. The drug hybrid was fabricated through a propionyl ester linker between DHA and EB. The antiplasmodial activity of the new hybrid was tested in vitro on the blood stages of Plasmodium falciparum (chloroquine-sensitive, 3D7 strain) and also evaluated in vivo by Peters' standard test in mice infected with Plasmodium berghei. The hybrid compound was also assessed for in vivo toxicity. Among all the compounds studied, a DHA-EB hybrid showed an appropriate inhibition percentage (53%) was at a very low dose (0.65 nM). The highest in vivo antimalarial activity until the 9th day was related to DHA-EB in a low dose (0.5 mg/kg). Also, the most survival rate was observed in the test group of hybrid compound at a dose of 1.5 mg/kg for 22 days. No external changes were identified in the toxicity assay. The weight of internal organs of treated animals and that of controls indicated nontoxicity of DHA-EB even after 60 days of consumption. In vitro and in vivo studies substantiated that DHA-EB hybrid has the potential for developing as a safe antimalarial drug.

Compounds Consisting of Quinazoline, Ibuprofen, and Amino Acids with Cytotoxic and Anti-Inflammatory Effects

In this research work, a series of 16 quinazoline derivatives bearing ibuprofen and an amino acid were designed as inhibitors of epidermal growth factor receptor tyrosine kinase domain (EGFR-TKD) and cyclooxygenase-2 (COX-2) with the intention of presenting dual action in their biological behavior. The designed compounds were synthesized and assessed for cytotoxicity on epithelial cancer cells lines (AGS, A-431, MCF-7, MDA-MB-231) and epithelial non-tumorigenic cell line (HaCaT). From this evaluation, derivative 6 was observed to exhibit higher cytotoxic potency (IC50) than gefitinib (reference drug) on three cancer cell lines (0.034 μM in A-431, 2.67 μM in MCF-7, and 3.64 μM in AGS) without showing activity on the non-tumorigenic cell line (>100 μM). Furthermore, assessment of EGFR-TKD inhibition by 6 showed a discreet difference compared to gefitinib. Additionally, 6 was used to conduct an in vivo anti-inflammatory assay using the 12-O-tetradecanoylphorbol-3-acetate (TPA) method, and it was shown to be 5 times more potent than ibuprofen. Molecular dynamics studies of EGFR-TKD revealed interactions between compound 6 and M793. On the other hand, one significant interaction was observed for COX-2, involving S531. The RMSD graph indicated that the ligand remained stable in 50 ns.

Triggering Breast Cancer Apoptosis via Cyclin-Dependent Kinase Inhibition and DNA Damage by Novel Pyrimidinone and 1,2,4-Triazolo[4,3-a]pyrimidinone Derivatives

Combinations of apoptotic inducers are common clinical practice in breast cancer. However, their efficacy is limited by the heterogeneous pharmacokinetic profiles. An advantageous alternative is merging their molecular entities in hybrid multitargeted scaffolds exhibiting synergistic activities and uniform distribution. Herein, we report apoptotic inducers simultaneously targeting DNA and CDK-2 (cyclin-dependent kinase-2) inspired by studies revealing that CDK-2 inhibition sensitizes breast cancer to DNA-damaging agents. Accordingly, rationally substituted pyrimidines and triazolopyrimidines were synthesized and assayed by MTT against MCF-7, MDA-MB231, and Wi-38 cells compared to doxorubicin. The N-(4-amino-2-((2-hydrazinyl-2-oxoethyl)thio)-6-oxo-1,6-dihydropyrimidin-5-yl)acetamide 5 and its p-nitrophenylhydrazone 8 were the study hits against MCF-7 (IC50 = 0.050 and 0.146 μM) and MDA-MB231 (IC50 = 0.826 and 0.583 μM), induced DNA damage at 10.64 and 30.03 nM, and inhibited CDK-2 (IC50 = 0.172 and 0.189 μM). 5 induced MCF-7 apoptosis by 46.75% and disrupted cell cycle during S phase. Docking and MD simulations postulated their stable key interactions.

Skeletal editing of pyridines through atom-pair swap from CN to CC

Skeletal editing is a straightforward synthetic strategy for precise substitution or rearrangement of atoms in core ring structures of complex molecules; it enables quick diversification of compounds that is not possible by applying peripheral editing strategies. Previously reported skeletal editing of common arenes mainly relies on carbene- or nitrene-type insertion reactions or rearrangements. Although powerful, efficient and applicable to late-stage heteroarene core structure modification, these strategies cannot be used for skeletal editing of pyridines. Here we report the direct skeletal editing of pyridines through atom-pair swap from CN to CC to generate benzenes and naphthalenes in a modular fashion. Specifically, we use sequential dearomatization, cycloaddition and rearomatizing retrocycloaddition reactions in a one-pot sequence to transform the parent pyridines into benzenes and naphthalenes bearing diversified substituents at specific sites, as defined by the cycloaddition reaction components. Applications to late-stage skeletal diversification of pyridine cores in several drugs are demonstrated.

Disclosure of cinnamic acid/4,9-diaminoacridine conjugates as multi-stage antiplasmodial hits

4,9-diaminoacridines with reported antiplasmodial activity were coupled to different trans-cinnamic acids, delivering a new series of conjugates inspired by the covalent bitherapy concept. The new compounds were more potent than primaquine against hepatic stages of Plasmodium berghei, although this was accompanied by cytotoxic effects on Huh-7 hepatocytes. Relevantly, the conjugates displayed nanomolar activities against blood stage P. falciparum parasites, with no evidence of hemolytic effects below 100 µM. Moreover, the new compounds were at least 25-fold more potent than primaquine against P. falciparum gametocytes. Thus, the new antiplasmodial hits disclosed herein emerge as valuable templates for the development of multi-stage antiplasmodial drug candidates.

The first-in-class pyrazole-based dual InhA-VEGFR inhibitors towards integrated antitubercular host-directed therapy

Several facets of the host response to tuberculosis have been tapped for clinical investigation, especially targeting angiogenesis mediated by VEGF signaling from infected macrophages. Herein, we rationalized combining the antiangiogenic effects of VEGFR-2 blockade with direct antitubercular InhA inhibition in single hybrid dual inhibitors as advantageous alternatives to the multidrug regimens. Inspired by expanded triclosans, the ether ligation of triclosan was replaced by rationalized linkers to assemble the VEGFR-2 inhibitors thematic scaffold. Accordingly, new series of 3-(p-chlorophenyl)-1-phenylpyrazole derivatives tethered to substituted ureas and their isosteres were synthesized, evaluated against Mycobacterium tuberculosis virulent cell line H37Rv, and assessed for their InhA inhibitory activities. The urea derivatives 8d and 8g exhibited the most promising antitubercular activity (MIC = 6.25 µg/mL) surpassing triclosan (MIC = 20 µg/mL) with potential InhA inhibition, thus identified as the study hits. Interestingly, both compounds inhibited VEGFR-2 at nanomolar IC50 (15.27 and 24.12 nM, respectively). Docking and molecular dynamics simulations presumed that 8d and 8g could bind to their molecular targets InhA and VEGFR-2 posing essential stable interactions shared by the reference inhibitors triclosan and sorafenib. Finally, practical LogP, Lipinski's parameters and in silico ADMET calculations highlighted their drug-likeness as novel leads in the arsenal against TB.

Synthesis, antitumor evaluation and computational study of thiazolidinone derivatives of dehydroabietic acid-based B ring-fused-thiazole

In an attempt to search for new natural product-based antitumor agents, a series of novel thiazolidinone derivatives of dehydroabietic acid-based B ring-fused-thiazole were designed and synthesized. The primary antitumor tests showed that compounds 5 m exhibited almost the best inhibitory activity against the tested cancer cells. The computational study suggested NOTCH1, IGF1R, TLR4, and KDR were the core targets of the title compounds, and the IC50 of SCC9 and Cal27 is strong correlation with the binding ability of TLR4 and compounds.

Synthesis of Novel Triazine-Based Chalcones and 8,9-dihydro-7H-pyrimido[4,5-b][1,4]diazepines as Potential Leads in the Search of Anticancer, Antibacterial and Antifungal Agents

This study presents the synthesis of four series of novel hybrid chalcones (20,21)a-g and (23,24)a-g and six series of 1,3,5-triazine-based pyrimido[4,5-b][1,4]diazepines (28-33)a-g and the evaluation of their anticancer, antibacterial, antifungal, and cytotoxic properties. Chalcones 20b,d, 21a,b,d, 23a,d-g, 24a-g and the pyrimido[4,5-b][1,4]diazepines 29e,g, 30g, 31a,b,e-g, 33a,b,e-g exhibited outstanding anticancer activity against a panel of 60 cancer cell lines with GI50 values between 0.01 and 100 μM and LC50 values in the range of 4.09 μM to >100 μM, several of such derivatives showing higher activity than the standard drug 5-fluorouracil (5-FU). On the other hand, among the synthesized compounds, the best antibacterial properties against N. gonorrhoeae, S. aureus (ATCC 43300), and M. tuberculosis were exhibited by the pyrimido[4,5-b][1,4]diazepines (MICs: 0.25-62.5 µg/mL). The antifungal activity studies showed that triazinylamino-chalcone 29e and triazinyloxy-chalcone 31g were the most active compounds against T. rubrum and T. mentagrophytes and A. fumigatus, respectively (MICs = 62.5 μg/mL). Hemolytic activity studies and in silico toxicity analysis demonstrated that most of the compounds are safe.

Curcumin hybrid molecules for the treatment of Alzheimer's disease: Structure and pharmacological activities

Alzheimer's disease (AD) is the most common neurodegenerative disease among the elderly. Contemporary treatments can only relieve symptoms but fail to delay disease progression. Curcumin is a naturally derived compound that has demonstrated significant therapeutic effects in AD treatment. Recently, molecular hybridization has been utilized to combine the pharmacophoric groups present in curcumin with those of other AD drugs, resulting in a series of novel compounds that enhance the therapeutic efficacy through multiple mechanisms. In this review, we firstly provide a concise summary of various pathogenetic hypotheses of AD and the mechanism of action of curcumin in AD, as well as the concept of molecular hybridization. Subsequently, we focus on the recent development of hybrid molecules derived from curcumin, summarizing their structures and pharmacological activities, including cholinesterase inhibitory activity, Aβ aggregation inhibitory activity, antioxidant activity, and other activities. The structure-activity relationships were further discussed.

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).

Synthesis and antibacterial activity of FST and its effects on inflammatory response and intestinal barrier function in mice infected with Escherichia coli O78

Pathogenic Escherichia coli (E. coli) can cause intestinal diseases in humans and livestock, damage the intestinal barrier, increase systemic inflammation, and seriously threaten human health and the development of animal husbandry. In this study, we designed and synthesized a novel conjugate florfenicol sulfathiazole (FST) based on drug combination principles, and investigated its antibacterial activity in vitro and its protective effect on inflammatory response and intestinal barrier function in E. coli O78-infected mice in vivo. The results showed that FST had superior antibacterial properties and minimal cytotoxicity compared with its prodrugs as florfenicol and sulfathiazole. FST protected mice from lethal E. coli infection, reduced clinical signs of inflammation, reduced weight loss, alleviated intestinal structural damage. FST decreased the expression of inflammatory cytokines IL-1β, IL-6, TNF-α, and increased the expression of claudin-1, Occludin, and ZO-1 in the jejunum, improved the intestinal barrier function, and promoted the absorption of nutrients. FST also inhibited the expression of TLR4, MyD88, p-p65, and p-p38 in the jejunum. The study may lay the foundation for the development of FST as new drugs for intestinal inflammation and injury in enteric pathogen infection.

An overview on the antimalarial activity of 1,2,4-trioxanes, 1,2,4-trioxolanes and 1,2,4,5-tetraoxanes

The demand for novel, fast-acting, and effective antimalarial medications is increasing exponentially. Multidrug resistant forms of malarial parasites, which are rapidly spreading, pose a serious threat to global health. Drug resistance has been addressed using a variety of strategies, such as targeted therapies, the hybrid drug idea, the development of advanced analogues of pre-existing drugs, and the hybrid model of resistant strains control mechanisms. Additionally, the demand for discovering new potent drugs grows due to the prolonged life cycle of conventional therapy brought on by the emergence of resistant strains and ongoing changes in existing therapies. The 1,2,4-trioxane ring system in artemisinin (ART) is the most significant endoperoxide structural scaffold and is thought to be the key pharmacophoric moiety required for the pharmacodynamic potential of endoperoxide-based antimalarials. Several derivatives of artemisinin have also been found as potential treatments for multidrug-resistant strain in this area. Many 1,2,4-trioxanes, 1,2,4-trioxolanes, and 1,2,4,5-tetraoxanes derivatives have been synthesised as a result, and many of these have shown promise antimalarial activity both in vivo and in vitro against Plasmodium parasites. As a consequence, efforts to develop a functionally straight-forward, less expensive, and vastly more effective synthetic pathway to trioxanes continue. This study aims to give a thorough examination of the biological properties and mode of action of endoperoxide compounds derived from 1,2,4-trioxane-based functional scaffolds. The present system of 1,2,4-trioxane, 1,2,4-trioxolane, and 1,2,4,5-tetraoxane compounds and dimers with potentially antimalarial activity will be highlighted in this systematic review (January 1963-December 2022).

An updated review of chemical compounds with anti-Toxoplasma gondii activity

The opportunistic apicomplexan parasite Toxoplasma gondii is the etiologic agent for toxoplasmosis, which can infect a widespread range of hosts, particularly humans and warm-blooded animals. The present chemotherapy to treat or prevent toxoplasmosis is deficient and is based on diverse drugs such as atovaquone, trimethoprim, spiramycine, which are effective in acute toxoplasmosis. Therefore, a safe chemotherapy is required for toxoplasmosis considering that its responsible agent, T. gondii, provokes severe illness and death in pregnant women and immunodeficient patients. A certain disadvantage of the available treatments is the lack of effectiveness against the tissue cyst of the parasite. A safe chemotherapy to combat toxoplasmosis should be based on the metabolic differences between the parasite and the mammalian host. This article covers different relevant molecular targets to combat this disease including the isoprenoid pathway (farnesyl diphosphate synthase, squalene synthase), dihydrofolate reductase, calcium-dependent protein kinases, histone deacetylase, mitochondrial electron transport chain, etc.

Development of trisubstituted thiophene-3-arboxamide selenide derivatives as novel EGFR kinase inhibitors with cytotoxic activity

Overexpression of EGFR is one of the eminent oncogenic drivers detected in the development of several human cancers. The increasing incidences of mutation-based resistance in the tyrosine kinase domain call upon the need for the development of a newer class of small-molecule TK inhibitors. Accordingly, a new series of symmetrical trisubstituted thiophene-3-carboxamide selenide derivatives was developed via the hybridization of complementary pharmacophores. Most of the compounds showed a modest to excellent antiproliferative action at 20 μM concentration. The utmost antiproliferative activity was portrayed by compound 16e on the selected cancer cell lines with IC50 < 9 μM, the lowest being 3.20 ± 0.12 μM in the HCT116 cell line. Further, it also displayed an impressive EGFR kinase inhibition with an IC50 value of 94.44 ± 2.22 nM concentration. As a corollary of the reported EGFR inhibition, the nature, energy, and stability of the binding interactions were contemplated via in silico studies.

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

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

Synthesis, Antimalarial, Antileishmanial, and Cytotoxicity Activities and Preliminary In Silico ADMET Studies of 2-(7-Chloroquinolin-4-ylamino)ethyl Benzoate Derivatives

A series of heterocyclic chloroquine hybrids, containing a chain of two carbon atoms at position four of the quinolinic chain and acting as a link between quinoline and several benzoyl groups, is synthesized and screened in vitro as an inhibitor of β-hematin formation and in vivo for its antimalarial activity against chloroquine-sensitive strains of Plasmodium berghei ANKA in this study. The compounds significantly reduced haeme crystallization, with IC50 values < 10 µM. The values were comparable to chloroquine's, with an IC50 of 1.50 ± 0.01 µM. The compounds 4c and 4e prolonged the average survival time of the infected mice to 16.7 ± 2.16 and 14.4 ± 1.20 days, respectively. We also studied the effect of the compounds 4b, 4c, and 4e on another important human parasite, Leishmania mexicana, which is responsible for cutaneous leishmaniasis, demonstrating a potential leishmanicidal effect against promasigotes, with an IC50 < 10 µM. Concerning the possible mechanism of action of these compounds on Lesihmania mexicana, we performed experiments demonstrating that these three compounds could induce the collapse of the parasite mitochondrial electrochemical membrane potential (Δφ). The in vitro cytotoxicity assays against mammalian cancerous and noncancerous human cell lines showed that the studied compounds exhibit low cytotoxic effects. The ADME/Tox analysis predicted moderate lipophilicity values, low unbound fraction values, and a poor distribution for these compounds. Therefore, moderate bioavailability was expected. We calculated other molecular descriptors, such as the topological polar surface area, according to Veber's rules, and except for 2 and 4i, the rest of the compounds violated this descriptor, demonstrating the low antimalarial activity of our compounds in vivo.

Battling colorectal cancer via s-triazine-based MMP-10/13 inhibitors armed with electrophilic warheads for concomitant ferroptosis induction; the first-in-class dual-acting agents

There is an increasing interest in halting CRC by combining ferroptosis with other forms of tumor cell death. However, ferroptosis induction is seldom studied in tandem with inhibiting MMPs. A combination that is expected to enhance the therapeutic outcome based on mechanistic ferroptosis studies highlighting the interplay with MMPs, especially MMP-13 associated with CRC metastasis and poor prognosis. Herein, we report new hybrid triazines capable of simultaneous MMP-10/13 inhibition and ferroptosis induction bridging the gap between their anticancer potentials. The MMP-10/13 inhibitory component of the scaffold was based on the non-hydroxamate model inhibitors. s-Triazine was rationalized as the core inspired by altretamine, an FDA-approved ferroptosis inducer. The ferroptosis pharmacophores were then installed as Michael acceptors via triazole-based spacers. The electrophilic reactivity was tuned by incorporating cyano and/or substituted phenyl groups influencing their electronic and steric properties and enriching the SAR study. Initial screening revealed the outstanding cytotoxicity profiles of the nitrophenyl-tethered chalcone 5e and the cyanoacrylohydrazides bearing p-fluorophenyl 9b and p-bromophenyl 9d appendages. 9b and 9d surpassed NNGH against MMP-10 and -13, especially 9d (IC50 = 0.16 μM). Ferroptosis studies proved that 9d depleted GSH in HCT-116 cells by a relative fold decrement of 0.81 with modest direct GPX4 inhibition, thus inducing lipid peroxidation, the hallmark of ferroptosis, by 1.32 relative fold increment. Docking presumed that 9d could bind to the MMP-10 S1' pocket and active site His221, extend through the MMP-13 hydrophobic pocket, and interact covalently with the GPX4 catalytic selenocysteine. 9d complexed with ferrous oxide nanoparticles was 7.5 folds more cytotoxic than its free precursor against HCT-116 cells. The complex-induced intracellular iron overload, depleted GSH with a relative fold decrement of 0.12, consequently triggering lipid peroxidation and ferroptosis by a 3.94 relative fold increment. Collectively, 9d could be a lead for tuning MMPs selectivity and ferroptosis induction potential to maximize the benefit of such a combination.

Dual Role of TiO(acac)2 as a Reagent and an Activator/Catalyst: A Study on the Solvent Dependent Product Formation

The dual operation of a chemical species in synthetic chemistry is an intriguing and relatively unexplored phenomenon. The application of such a species is expected to reduce the use of multiple reaction partners and catalysts/activators. Herein, we report a simple and easy-to-use protocol for the twin application of TiO(acac)2 , as a reagent and an activator to synthesize β-enamino ketones with amines in acetonitrile. The same early transition metal precursor when employed in N,N-dimethylformamide with the amines, resulted in the formation of the substituted amides. Both reactions were explored with various substrates to check the viability of the present protocol. Moreover, experimental studies were conducted to understand the mechanism of both reactions.

Dihydroartemisinin-Ursodeoxycholic Bile Acid Hybrids in the Fight against SARS-CoV-2

Here, we propose the molecular hybridization of dihydroartemisinin (DHA) and ursodeoxycholic bile acid (UDCA), approved drugs, for the preparation of antiviral agents against SARS-CoV-2. DHA and UDCA were selected on the basis of their recently demonstrated in vitro activity against SARS-CoV-2. A selection of DHA-UDCA-based hybrids obtained by varying the nature of the linkage and the bile acid conjugation point as well as unconjugated DHA and UDCA were tested in vitro for cytotoxicity and anti-SARS-CoV-2 activity on Vero E6 and Calu-3 human lung cells. The hybrid DHA-t-UDCMe, obtained by conjugation via click chemistry on a gram scale, was identified as a potential candidate for SARS-CoV-2 infection treatment due to significant reduction of viral replication, possibly involving ACE2 downregulation, no cytotoxicity, and chemical stability.

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.

Recent developments in the synthesis of hybrid antimalarial drug discovery

In this 21st century, Malaria remains a global burden and causes massive economic trouble to disease-endemic nations. The control and eradication of malaria is a major challenge that requires an urgent need to develop novel antimalarial drugs. To overcome the aforementioned situation, several researchers have given significant effort to develop hybrid antimalarial agents in the search for new antimalarial drugs. Hence, we have summarized those developments of hybrid antimalarial agents from 2017 to till date. This review illustrates the current progress in the recent synthesis of hybrid antimalarial agents along with focusing on their antimalarial evaluation to find the most potent hybrids. This present mini-review will also be useful for the scientific community for the development of new antimalarial drugs to eradicate malaria.

Novel coumarin-chalcone derivatives: Synthesis, characterization, antioxidant, cyclic voltammetry, molecular modelling and biological evaluation studies as acetylcholinesterase, α-glycosidase, and carbonic anhydrase inhibitors

In this study, a total of 12 coumarin-chalcone derivatives, 6 of which are original were synthesized. The structures of the newly synthesized compounds were elucidated by 1H NMR, 13C NMR, IR, and elemental analysis methods (7g-7l). The antioxidant potencies measured by using CUPRAC method (Trolox equivalent total antioxidant capacity) were as follows: 7j > 7i > 7c > 7d > 7k > 7l > 7f > 7h > 7e > 7g > 7a > 7b. Furthermore, the compounds were evaluated against human carbonic anhydrases I, II, acetylcholinesterase and α-glycosidase enzymes. Compounds 7c, 7e, 7g, 7i, 7j and 7l showed promising human carbonic anhydrase I inhibition compared to the standard Acetazolamide (Ki: 16.64 ± 4.72-49.82 ± 5.82 nM vs Ki: 57.64 ± 5.41 nM). In addition, all compounds exhibited strong inhibition against acetylcholinesterase and α-glycosidase. Ki values were between 2.39 ± 0.97-9.35 ± 3.95 nM (Tacrine Ki: 13.78 ± 4.36 nM) for acetylcholinesterase, and 14.49 ± 8.51-75.67 ± 26.38 nM (Acarbose Ki: 12600 ± 78.00 nM) for α-glycosidase. Binding of 7g was predicted using molecular docking and stability of the complex was confirmed with molecular dynamics simulations which shed a light on the observed activity against acetylcholinesterase. Finally, cyclic voltammetry was also used for the electrochemical characterization of the synthesized compounds.

Hybrid molecules based on an emodin scaffold. Synthesis and activity against SARS-CoV-2 and Plasmodium

Since the Covid-19 epidemic, it has been clear that the availability of small and affordable drugs that are able to efficiently control viral infections in humans is still a challenge in medicinal chemistry. The synthesis and biological activities of a series of hybrid molecules that combine an emodin moiety and other structural moieties expected to act as possible synergistic pharmacophores in a single molecule were studied. Emodin has been reported to block the entry of the SARS-CoV-2 virus into human cells and might also inhibit cytokine production, resulting in the reduction of pulmonary injury induced by SARS-CoV-2. The pharmacophore associated with emodin was either a polyamine residue (emodin-PA series), a choice driven by the fact that a natural alkyl PA like spermine and spermidine play regulatory roles in immune cell functions, or a diphenylmethylpiperazine derivative of the norchlorcyclizine series (emoxyzine series). In fact, diphenylmethylpiperazine antagonists of the H1 histamine receptor display activity against several viruses by multiple interrelated mechanisms. In the emoxyzine series, the most potent drug against SARS-CoV-2 was (R)-emoxyzine-2, with an EC50 value = 1.9 μM, which is in the same range as that of the reference drug remdesivir. However, the selectivity index was rather low, indicating that the dissociation of antiviral potency and cytotoxicity remains a challenge. In addition, since emodin was also reported to be a relatively high-affinity inhibitor of the virulence regulator FIKK kinase from the malaria parasite Plasmodium vivax, the antimalarial activity of the synthesized hybrid compounds has been evaluated. However, these molecules cannot efficiently compete with the currently used antimalarial drugs.

Evaluation of Anti-Inflammatory and Anti-Tubercular Activity of 4-Methyl-7-Substituted Coumarin Hybrids and Their Structure Activity Relationships

Four sets of previously synthesized 4-methyl-7-substituted coumarin derivatives were screened for their in vitro anti-inflammatory and anti-tubercular activities. The anti-inflammatory potential of 3a-t, 5a-o, 6a-n, and 7a-f synthesized compounds was evaluated by an anti-denaturation assay using diclofenac sodium as the reference standard. Evaluation of the anti-tuberculous activity of the mentioned compounds was performed by the Resazurin test method against four different TB strains using rifampicin and isoniazid as reference drugs. Based on the anti-inflammatory results, compounds 3o, 5f, 6c, and 7d proved to be the most active compounds in their respective series. Additionally, compounds 3k-n, 5b-d, 6d-f, 6k, 7a, and 7f were found to be the most potent anti-tuberculous agents. In fact, most of the screened compounds exhibited promising activity profiles compared to the respective standard drugs. The structure-activity connections revealed a few intriguing aspects, indicating that the presence of electron-donating and nitrogen-rich fragments boost the anti-inflammatory effects of the examined compounds. However, the presence of electron-withdrawing substituents was required to boost the anti-tubercular activity of the evaluated compounds.

Discovery of Novel Naphthoquinone-Chalcone Hybrids as Potent FGFR1 Tyrosine Kinase Inhibitors: Synthesis, Biological Evaluation, and Molecular Modeling

This work presents a flexible synthesis of 10 novel naphthoquinone-chalcone derivatives (1-10) by nucleophilic substitution of readily accessible aminochalcones and 2,3-dichloro-1,4-naphthoquinone. All compounds displayed broad-spectrum cytotoxic activities against all the tested cancer cell lines (i.e., HuCCA-1, HepG2, A549, MOLT-3, T47D, and MDA-MB-231) with IC50 values in the range of 0.81-62.06 μM, especially the four most potent compounds 1, 3, 8, and 9. The in vitro investigation on the fibroblast growth factor receptor 1 (FGFR1) inhibitory effect indicated that eight derivatives (1-2, 4-5, and 7-10) were active FGFR1 inhibitors (IC50 = 0.33-3.13 nM) with more potency than that of the known FGFR1 inhibitor, AZD4547 (IC50 = 12.17 nM). Promisingly, compounds 5 (IC50 = 0.33 ± 0.01 nM), 9 (IC50 = 0.50 ± 0.04 nM), and 7 (IC50 = 0.85 ± 0.08 nM) were the three most potent FGFR1 inhibitors. Molecular docking, molecular dynamics simulations, and MM/GBSA-based free energy calculation revealed that the key amino acid residues involved in the binding of the compounds 5, 7, and 9 and the target FGFR1 protein were similar with those of the AZD4547 (i.e., Val492, Lys514, Ile545, Val561, Ala640, and Asp641). These findings revealed that the newly synthesized naphthoquinone-chalcone scaffold is a promising structural feature for an efficient inhibition of FGFR1.

Natural product-inspired synthesis of coumarin-chalcone hybrids as potential anti-breast cancer agents

Twelve novel neo-tanshinlactone-chalcone hybrid molecules were constructed through a versatile methodology involving the Horner-Wadsworth-Emmons (HWE) olefination of 4-formyl-2H-benzo [h]chromen-2-ones and phosphonic acid diethyl esters, as the key step, and evaluated for anticancer activity against a series of four breast cancers and their related cell lines, viz. MCF-7 (ER + ve), MDA-MB-231 (ER-ve), HeLa (cervical cancer), and Ishikawa (endometrial cancer). The title compounds showed excellent to moderate in vitro anti-cancer activity in a range of 6.8-19.2 µM (IC50). Compounds 30 (IC50 = 6.8 µM and MCF-7; IC50 = 8.5 µM and MDA-MB-231) and 31 (IC50 = 14.4 µM and MCF-7; IC50 = 15.7 µM and MDA-MB-231) exhibited the best activity with compound 30 showing more potent activity than the standard drug tamoxifen. Compound 30 demonstrated a strong binding affinity with tumor necrosis factor α (TNF-α) in molecular docking studies. This is significant because TNFα is linked to MCF-7 cancer cell lines, and it enhances luminal breast cancer cell proliferation by upregulating aromatase. Additionally, virtual ADMET studies confirmed that hybrid compounds 30 and 31 met Lipinski's rule; displayed high bioavailability, excellent oral absorption, favorable albumin interactions, and strong penetration capabilities; and improved blood-brain barrier crossing. Based on the aforementioned results, compound 30 has been identified as a potential anti-breast cancer lead molecule.

Molecular Hybridization as a Strategy for Developing Artemisinin-Derived Anticancer Candidates

Artemisinin is a natural compound extracted from Artemisia species belonging to the Asteraceae family. Currently, artemisinin and its derivatives are considered among the most significant small-molecule antimalarial drugs. Artemisinin and its derivatives have also been shown to possess selective anticancer properties, however, there are several limitations and gaps in knowledge that retard their repurposing as effective anticancer agents. Hybridization resulting from a covalent combination of artemisinin with one or more active pharmacophores has emerged as a promising approach to overcome several issues. The variety of hybridization partners allows improvement in artemisinin activity by tuning the ability of conjugated artemisinin to interact with various molecule targets involved in multiple biological pathways. This review highlights the current scenario of artemisinin-derived hybrids with potential anticancer activity. The synthetic approaches to achieve the corresponding hybrids and the structure-activity relationships are discussed to facilitate further rational design of more effective candidates.

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

In this paper, we have assessed the design, synthesis, characterization, anticancer properties, toxicity, and in silico study of 8-piperazinyl caffeinyl-triazolylmethyl derivatives as new caffeine hybrid conjugates. These compounds consist of four moieties comprising 8-caffeinyl, piperazinyl, 1,2,3-triazolyl, and alkyl substituents. The synthesis of these compounds was started by bromination of caffeine to attain 8-BC, SNAr reaction with piperazine to acquire 8-PC, N-propargylation of 8-PC and finally click Huisgen cycloaddition with diverse alkyl azides. These compounds were in vitro tested against two significant cancer cell lines comprising breast cancer MCF-7 (ATCC HTB-22) and melanoma cancer A-375 (ATCC CRL-1619) cell lines and activities compared with methotrexate (MTX) as a reference drug. Anticancer assessments indicated 12j (IC50 = 323 ± 2.6) and 12k (IC50 = 175 ± 3.2) were the most potent compounds against A-375 and MCF-7 cell growth, respectively and their activities were even stronger than MTX (IC50 = 418 ± 2 for A375 and IC50 = 343 ± 3.6 for MCF-7). Toxicities were determined by screening compounds against normal cell line HEK-293 (ATCC CRL-11268) and indicated that except 12i (IC50 = 371 ± 2.3), 12j (IC50 = 418 ± 2.4), and MTX (IC50 = 199 ± 2.4), all compounds are non-toxic. Docking was conducted for 12j and 12k and determined the strong binding affinities to B-RAF kinase and hDHFR enzymes, respectively. In silico pharmacokinetic and physiochemical profiles of tested compounds were investigated which indicated that most compounds obeyed Lipinski's rule of five (RO5). The DFT study on M06-2X/6-311G (d,p) was used to indicate HOMO, LUMO, MEP, and other parameters for a better understanding of 12j and 12k reactivity. Owing to anticancer properties, toxicity, and in silico data, 12j and 12k can be proposed for further research in the future.

Nanoformulation-Based 1,2,3-Triazole Sulfonamides for Anti-Toxoplasma In Vitro Study

Toxoplasma gondii is deemed a successful parasite worldwide with a wide range of hosts. Currently, a combination of pyrimethamine and sulfadiazine serves as the first-line treatment; however, these drugs have serious adverse effects. Therefore, it is imperative to focus on new therapies that produce the desired effect with the lowest possible dose. The designation and synthesis of sulfonamide-1,2,3-triazole hybrids (3a-c) were performed to create hybrid frameworks. The newly synthesized compounds were loaded on chitosan nanoparticles (CNPs) to form nanoformulations (3a.CNP, 3b.CNP, 3c.CNP) for further in vitro investigation as an anti-Toxoplasma treatment. The current study demonstrated that all examined compounds were active against T. gondii in vitro relative to the control drug, sulfadiazine. 3c.CNP showed the best impact against T. gondii with the lowest IC50 value of 3.64 µg/mL. Using light microscopy, it was found that Vero cells treated with the three nanoformulae showed remarkable morphological improvement, and tachyzoites were rarely seen in the treated cells. Moreover, scanning and transmission electron microscopic studies confirmed the efficacy of the prepared nanoformulae on the parasites. All of them caused parasite ultrastructural damage and altered morphology, suggesting a cytopathic effect and hence confirming their promising anti-Toxoplasma activity.

Finding a Novel Chalcone-Cinnamic Acid Chimeric Compound with Antiproliferative Activity against MCF-7 Cell Line Using a Free-Wilson Type Approach

In this work, we carried out the design and synthesis of new chimeric compounds from the natural cytotoxic chalcone 2',4'-dihydroxychalcone (2',4'-DHC, A) in combination with cinnamic acids. For this purpose, a descriptive and predictive quantitative structure-activity relationship (QSAR) model was developed to study the chimeric compounds' anti-cancer activities against human breast cancer MCF-7, relying on the presence or absence of structural motifs in the chalcone structure, like in a Free-Wilson approach. For this, we used 207 chalcone derivatives with a great variety of structural modifications over the α and β rings, such as halogens (F, Cl, and Br), heterocyclic rings (piperazine, piperidine, pyridine, etc.), and hydroxyl and methoxy groups. The multilinear equation was obtained by the genetic algorithm technique, using logIC₅₀ as a dependent variable and molecular descriptors (constitutional, topological, functional group count, atom-centered fragments, and molecular properties) as independent variables, with acceptable statistical parameter values (R2 = 86.93, Q2_LMO = 82.578, Q2_BOOT = 80.436, and Q2_EXT = 80.226), which supports the predictive ability of the model. Considering the aromatic and planar nature of the chalcone and cinnamic acid cores, a structural-specific QSAR model was developed by incorporating geometrical descriptors into the previous general QSAR model, again, with acceptable parameters (R2 = 85.554, Q2_LMO = 80.534, Q2_BOOT = 78.186, and Q2_EXT = 79.41). Employing this new QSAR model over the natural parent chalcone 2',4'-DHC (A) and the chimeric compound 2'-hydroxy,4'-cinnamate chalcone (B), the predicted cytotoxic activity was achieved with values of 55.95 and 17.86 µM, respectively. Therefore, to corroborate the predicted cytotoxic activity compounds A and B were synthesized by two- and three-step reactions. The structures were confirmed by ¹H and ¹³C NMR and ESI+MS analysis and further evaluated in vitro against HepG2, Hep3B (liver), A-549 (lung), MCF-7 (breast), and CasKi (cervical) human cancer cell lines. The results showed IC₅₀ values of 11.89, 10.27, 56.75, 14.86, and 29.72 µM, respectively, for the chimeric cinnamate chalcone B. Finally, we employed B as a molecular scaffold for the generation of cinnamate candidates (C-K), which incorporated structural motifs that enhance the cytotoxic activity (pyridine ring, halogens, and methoxy groups) according to our QSAR model. ADME/tox in silico analysis showed that the synthesized compounds A and B, as well as the proposed chalcones C and G, are the best candidates with adequate drug-likeness properties. From all these results, we propose B (as a molecular scaffold) and our two QSAR models as reliable tools for the generation of anti-cancer compounds over the MCF-7 cell line.

Synthesis of ursolic acid arylidene-hydrazide hybrid compounds and investigation of their cytotoxic and antimicrobial effects

In this study, 13 new hybrid compounds (7a-m) were synthesised starting from ursolic acid, and their cytotoxic activities were investigated on the BEAS-2B and A549 cell lines. In addition, the synthesised compounds were tested against Staphylococcus aureus, Escherichia coli, and Candida albicans to determine their anti-microbial properties. The hybrid compounds that exhibited the lowest cytotoxicity against the BEAS-2B were 7k, 7b, and 7g. The cytotoxicity of the compounds against A549 was evaluated, the IC50 value of 7k, 7b, and 7g are found as 0.15 µM, 0.31 µM, and 0.26 µM, respectively. The results showed that the selectivity of 7k was 7 times higher than doxorubicin against the A549 cells. According to the antimicrobial activity studies 7c is found as the most effective compound against S. aureus. Almost all compounds showed a similar inhibition potential against E. coli and C. albicans.

New 4-(N-cinnamoylbutyl)aminoacridines as potential multi-stage antiplasmodial leads

A novel family of 4-aminoacridine derivatives was obtained by linking this heteroaromatic core to different trans-cinnamic acids. The 4-(N-cinnamoylbutyl)aminoacridines obtained exhibited in vitro activity in the low- or sub-micromolar range against (i) hepatic stages of Plasmodium berghei, (ii) erythrocytic forms of Plasmodium falciparum, and (iii) early and mature gametocytes of Plasmodium falciparum. The most active compound, having a meta-fluorocinnamoyl group linked to the acridine core, was 20- and 120-fold more potent, respectively, against the hepatic and gametocyte stages of Plasmodium infection than the reference drug, primaquine. Moreover, no cytotoxicity towards mammalian and red blood cells at the concentrations tested was observed for any of the compounds under investigation. These novel conjugates represent promising leads for the development of new multi-target antiplasmodials.

Investigation of the Antifungal and Anticancer Effects of the Novel Synthesized Thiazolidinedione by Ion-Conductance Microscopy

In connection with the emergence of new pathogenic strains of Candida, the search for more effective antifungal drugs becomes a challenge. Part of the preclinical trials of such drugs can be carried out using the innovative ion-conductance microscopy (ICM) method, whose unique characteristics make it possible to study the biophysical characteristics of biological objects with high accuracy and low invasiveness. We conducted a study of a novel synthesized thiazolidinedione's antimicrobial (for Candida spp.) and anticancer properties (on samples of the human prostate cell line PC3), and its drug toxicity (on a sample of the human kidney cell line HEK293). We used a scanning ion-conductance microscope (SICM) to obtain the topography and mechanical properties of cells and an amperometric method using Pt-nanoelectrodes to register reactive oxygen species (ROS) expression. All data and results are obtained and presented for the first time.

Cannabinoids as multifaceted compounds

Since ancient times, Cannabis and its preparations have found various applications such as for medical, recreational and industrial purposes. Subsequently the 1930s, legislation in many countries has restricted its use due to its psychotropic properties. More recently, the discovery of endocannabinoid system, including new receptors, ligands, and mediators, its role in maintaining the homeostasis of the human body and the possible implication in various physiological and pathophysiological processes has also been understood. Based on this evidence, researchers were able to develop new therapeutic targets for the treatment of various pathological disorders. For this purpose, Cannabis and cannabinoids were subjected for the evaluation of their pharmacological activities. The renewed interest in the medical use of cannabis for its potential therapeutic application has prompted legislators to take action to regulate the safe use of cannabis and products containing cannabinoids. However, each country has an enormous heterogeneity in the regulation of laws. Here, we are pleased to show a general and prevailing overview of the findings regarding cannabinoids and the multiple research fields such as chemistry, phytochemistry, pharmacology and analytics in which they are involved.

An ultrasound assisted, ionic liquid-molecular iodine synergy driven efficient green synthesis of pyrrolobenzodiazepine-triazole hybrids as potential anticancer agents

Herein, we report an efficient and eco-friendly, ultrasound assisted synthetic strategy for the construction of diversified pyrrolobenzodiazepine-triazole hybrids, which are potentially pharmaceutically important scaffolds, via a domino reaction involving intermolecular electrophilic substitution followed by intramolecular Huisgen 1,3-dipolar azide-alkyne cycloaddition. The USP of the reported protocol is the use of benign and inexpensive, recyclable molecular iodine-ionic liquid synergistic catalytic system cum reaction media for achieving the synthesis. The other salient features of this method are the use of mild reaction conditions, high yield and atom economy, operational simplicity, broad substrate scope and easy workup and purification. All the synthesized compounds were evaluated for in vitro anti-proliferative activity against various cancer cell lines. From among the synthesized title compounds, 9,9-dimethyl-8-phenyl-9H-benzo [b]pyrrolo [1,2-d][1,2,3]triazolo[5,1-g][1,4]diazepine (7) was found most to be the most active compound exhibiting IC₅₀ value of 6.60, 5.45, 7.85, 11.21, 12.24, 10.12, and 11.32 µM against MCF-7, MDA-MB-231, HeLa, SKOV-3, A549, HCT-116 and DLD-1 cell lines, respectively. Further the compounds were found to be non-toxic against normal human embryonic kidney (HEK-293) cell line.

Ru(II)-Catalyzed Synthesis of Fused Imidazo[1,2-a]pyridine-chromenones and Methylene-Tethered Bis-imidazo[1,2-a]pyridines and Regioselective O-Acetoxylation of Imidazo[1,2-a]pyridines

Herein, we disclose an unprecedented protocol via ruthenium-catalyzed annulation for the synthesis of 6H-chromeno[4',3':4,5]imidazo[1,2-a]pyridin-6-one, and functionalized 2-(3-formylimidazo[1,2-a]pyridin-2-yl)phenyl acetate has been revealed by intramolecular chelation-assisted C-H activation. Additionally, a one-pot approach for creating bis(2-phenylimidazo[1,2-a]pyridin-3-yl)methane (BIP) has been realized through ruthenium catalysis with the use of formic acid. This method was used in gram-scale synthesis of BIP and step-economical late-stage functionalization of a marketed drug, zolimidine, in good yield.

Rational Design of New Monoterpene-Containing Azoles and Their Antifungal Activity

Azole antifungals, including fluconazole, have long been the first-line antifungal agents in the fight against fungal infections. The emergence of drug-resistant strains and the associated increase in mortality from systemic mycoses has prompted the development of new agents based on azoles. We reported a synthesis of novel monoterpene-containing azoles with high antifungal activity and low cytotoxicity. These hybrids demonstrated broad-spectrum activity against all tested fungal strains, with excellent minimum inhibitory concentration (MIC) values against both fluconazole-susceptible and fluconazole-resistant strains of Candida spp. Compounds 10a and 10c with cuminyl and pinenyl fragments demonstrated up to 100 times lower MICs than fluconazole against clinical isolates. The results indicated that the monoterpene-containing azoles had much lower MICs against fluconazole-resistant clinical isolates of Candida parapsilosis than their phenyl-containing counterpart. In addition, the compounds did not exhibit cytotoxicity at active concentrations in the MTT assay, indicating potential for further development as antifungal agents.

New Hybrid Scaffolds Based on 5-FU/Curcumin: Synthesis, Cytotoxic, Antiproliferative and Pro-Apoptotic Effect

A series of 5-FU-Curcumin hybrids were synthesized, and their structures were elucidated by spectroscopic analysis. The synthesized hybrid compounds were evaluated in different colorectal cancer cell lines (SW480 and SW620) and in non-malignant cells (HaCaT and CHO-K1), to determine their chemopreventive potential. Hybrids 6a and 6d presented the best IC₅₀ value against the SW480 cell line with results of 17.37 ± 1.16 µM and 2.43 ± 0.33 µM, respectively. Similarly, compounds 6d and 6e presented IC₅₀ results of 7.51 ± 1.47 µM and 14.52 ± 1.31 µM, respectively, against the SW620 cell line. These compounds were more cytotoxic and selective than curcumin alone, the reference drug 5-fluorouracil (5-FU), and the equimolar mixture of curcumin and 5-FU. In addition, hybrids 6a and 6d (in SW480) and compounds 6d and 6e (in SW620) induced cell cycle arrest in S-phase, and, compounds 6d and 6e caused a significant increase in the sub-G0/G1 phase population in both cell lines. Hybrid 6e was also observed to induce apoptosis of SW620 cells with a respective increase in executioner caspases 3 and 7. Taken together, these results suggest that the hybrids could actively act on a colorectal cancer model, making them a privileged scaffold that could be used in future research.

Pyrazole derivatives of pyridine and naphthyridine as proapoptotic agents in cervical and breast cancer cells

Cancer is one of the leading causes of death worldwide. The increasing prevalence and resistance to chemotherapy is responsible for driving the search of novel molecules to combat this disease. In search of novel compounds with pro-apoptotic potential, pyrazolo-pyridine and pyrazolo-naphthyridine derivatives were investigated against cervical cancer (HeLa) and breast cancer (MCF-7) cells. The anti-proliferative activity was determined through the MTT assay. Potent compounds were then analyzed for their cytotoxic and apoptotic activity through a lactate dehydrogenase assay and fluorescence microscopy after propidium iodide and DAPI staining. Flow cytometry was used to determine cell cycle arrest in treated cells and pro-apoptotic effect was verified through measurement of mitochondrial membrane potential and activation of caspases. Compounds 5j and 5k were found to be most active against HeLa and MCF-7 cells, respectively. G0/G1 cell cycle arrest was observed in treated cancer cells. Morphological features of apoptosis were also confirmed, and an increased oxidative stress indicated the involvement of reactive oxygen species in apoptosis. The compound-DNA interaction studies demonstrated an intercalative mode of binding and the comet assay confirmed the DNA damaging effects. Finally, potent compounds demonstrated a decrease in mitochondrial membrane potential and increased levels of activated caspase-9 and -3/7 confirmed the induction of apoptosis in treated HeLa and MCF-7 cells. The present work concludes that the active compounds 5j and 5k may be used as lead candidates for the development of lead drug molecules against cervical and breast cancer.

Antimalarial activity assay of artesunate-3-chloro-4(4-chlorophenoxy) aniline in vitro and in mice models

The global spread of multi-drug resistant P. falciparum, P. vivax, and P. malariae strains and absence of long-term effective vaccine makes chemotherapy the mainstay of malaria control strategies in endemic settings. The Mossman's assay and the Organization for Economic Co-operation and Development (OECD), 2001 guideline 423, were used to determine the cytotoxicity and acute oral toxicity of a novel hybrid drug, artesunate-3-Chloro-4(4-chlorophenoxy) aniline (ATSA), in vitro and in vivo, respectively. A modified Desjardins method was used to screen for antiplasmodial activity using P. falciparum (3D₇ and W₂) strains in vitro. The Peter's 4-day suppressive tests (4DTs) was used to evaluate the in vivo antimalaria activity using P. berghei ANKA strain, lumefantrine resistant (LuR), and piperaquine resistant (PQR) P. berghei lines. In silico prediction of absorption, distribution, metabolism, excretion, and toxicity (ADMET) profiles was assayed using PreADMET online prediction tool. The reference drug in all experiments was artesunate (ATS). Statistical significance between ATSA's activities in treated and control mice was evaluated by one-way analysis of variance (ANOVA). Results show that inhibitory concentrations-50 (IC₅₀) of ATSA is 11.47 ± 1.3 (3D₇) and 1.45 ± 0.26 (W₂) against 4.66 ± 0.93 (3D₇) and 0.60 ± 0.15 (W₂) ng/ml of ATS with a selective index of 2180.91(3D₇) and a therapeutic index (TI) of > 71). No mortalities were observed in acute oral toxicity assays and mean weight differences for test and controls were statistically insignificant (P > 0.05). The in vivo activity of ATSA was above 40% with effective dosage-50 (ED₅₀) of 4.211, 2.601, and 3.875 mg/kg body weight against P. berghei ANKA, LuR, and PQR lines, respectively. The difference between treated and control mice was statistically significant (P < 0.05). ATSA has high intestinal absorption (HIA) > 95% and has medium human ether-a-go-go related gene (hERG) K⁺ channel inhibition risks. Preclinical and clinical studies on ATSA are recommended to evaluate its value in developing novel drugs for future management of multi-drug resistant malaria parasites.

G-Quadruplexes in c-MYC Promoter as Targets for Cancer Therapy

Cancer is a societal burden demanding innovative approaches. A major problem with the conventional chemotherapeutic agents is their strong toxicity and other side effects due to their poor selectivity. Uncontrolled proliferation of cancer cells is due to mutations, deletions, or amplifications in genes (oncogenes) encoding for proteins that regulate cell growth and division, such as transcription factors, for example, c-MYC. The direct targeting of the c-MYC protein has been attempted but so far unsuccessfully, as it lacks a definite binding site for the modulators. Meanwhile, another approach has been explored since the discovery that G-quadruplex secondary DNA structures formed in the guanine-rich sequences of the c-MYC promoter region can downregulate the transcription of this oncogene. Here, we will overview the major achievements made in the last decades towards the discovery of a new class of anticancer drugs targeting G-quadruplexes in the c-MYC promoter of cancer cells.

Therapeutic significance of molecular hybrids for breast cancer research and treatment

Worldwide, breast cancer is still a leading cause of cancer death in women. Indeed, over the years, several anti-breast cancer drugs have been developed; however, the complex heterogeneous nature of breast cancer disease reduces the applicability of conventional targeted therapies with the upsurge in side effects and multi-drug resistance. Molecular hybrids generated by a combination of two or more active pharmacophores emerged as a promising approach in recent years for the design and synthesis of anti-breast cancer drugs. The hybrid anti-breast cancer molecules are well known for their several advantages compared to the parent moiety. These hybrid forms of anti-breast cancer molecules demonstrated remarkable effects in blocking different pathways contributing to the pathogenies of breast cancer and improved specificity. In addition, these hybrids are patient compliant with reduced side effects and multi-drug resistance. The literature revealed that molecular hybrids are applied to discover and develop novel hybrids for various complex diseases. This review article highlights the recent progress (∼2018-2022) in developing molecular hybrids, including linked, merged, and fused hybrids, as promising anti-breast cancer agents. Furthermore, their design principles, biological potential, and future perspective are discussed. The provided information will lead to the development of novel anti-breast cancer hybrids with excellent pharmacological profiles in the future.

Benzoxazole-appended piperidine derivatives as novel anticancer candidates against breast cancer

Novel series of benzoxazole-appended piperidine derivatives were planned, synthesized and screened against two breast cancer cell lines. Considerable antiproliferative activity was observed for screened compounds (IC₅₀ = 33.32 ± 0.2 µM to 7.31 ± 0.43 µM and 1.66 ± 0.08 µM to 12.10 ± 0.57 µM) against MCF-7 and MDA-MB-231 cell lines respectively being more potent than doxorubicin (IC₅₀ = 8.20 ± 0.39 µM and 13.34 ± 0.63 µM respectively). Active compounds were submitted for enzyme inhibition assays when 4d and 7h demonstrated potent EGFR inhibition (0.08 ± 0.002 µM and 0.09 ± 0.002 µM respectively) compared to erlotinib (0.11 ± 0.003 µM). However, no one compound displayed effective ARO inhibition activity as tested compounds were less active than letrozole. Apoptosis inducing ability results implied that apoptosis was provoked by significant stimulation of caspase-9 protein levels (4.25-7.04-fold) upon treatment of MCF-7 cells with 4a, 7h, 9, 12e and 12f. Alternatively, MDA-MB-231 cells treated with 4d, 7a, 12b and 12c considerably increased caspase-9 levels (2.32-4.06-fold). Cell cycle arrest and annexin-V/Propidium iodide assays further confirmed apoptosis when tested compounds arrested cell cycle at various phases and demonstrated high annexin V binding affinity. Docking outcomes proved valuable binding affinities for compounds 4d and 7h to EGFR enzyme while compounds 4a and 12e, upon docking into the active site of ARO, failed to interact with heme, suggesting their inabilities to act as AIs. Therefore, these benzoxazoles can act as promising candidates exhibiting EGFR inhibition and apoptosis-promoting properties.