Quinoline-imidazole/benzimidazole derivatives as dual-/multi-targeting hybrids inhibitors with anticancer and antimicrobial activity

Pd(II) complexes bearing NNS pincer ligands: unveiling potent cytotoxicity against breast and pancreatic cancer

The continuously increasing rate of breast cancer is one of the major threats to female health worldwide. Recently, palladium complexes have emerged as impressive candidates with effective biocompatibility and anticancer activities. Hence, in the present study, we report a new series of palladium complexes bearing NNS pincer ligands for cytotoxicity studies. The reaction of thiophenol/4-chlorothiophenol/4-methylthiophenol/4-methoxythiophenol with 2-bromo-N-quinolin-8-yl-acetamide in the presence of sodium hydroxide in ethanol at 80 °C gave [C9H6N-NH-C(O)-CH2-S-Ar] [Ar = C6H5 (L1), C6H4Cl-4 (L2), C6H4Me-4 (L3), and C6H4-OMe-4 (L4)]. The corresponding reaction of L1-L4 with Na2PdCl4 in methanol at room temperature for 3 h resulted in complexes [(L1-H)PdCl] (C1), [(L2-H)PdCl] (C2), [(L3-H)PdCl] (C3), and [(L4-H)PdCl] (C4). All new compounds have been characterized by spectroscopic analyses. The structures of complexes C1, C3, and C4 have also been determined from single-crystal X-ray diffraction data. The cytotoxicities of L1-L4 and C1-C4 have been investigated for breast cancer 4T1 and pancreatic cancer MIA-PaCa-2 cells. The IC50 values for complexes C2 and C3 were observed to be comparable to or higher than those of cisplatin. The stressed morphology and cell death of cancerous cells were successfully observed through cellular morphology analysis and the assessment of cytoskeleton damage.

New insides into chimeric and hybrid azines derivatives with antifungal activity

During the last decades, five or six member rings azaheterocycles compounds appear to be an extremely valuable source of antifungal agents. Their use seems to be a very attractive solution in antifungal therapy and to overcome antifungal resistance in agriculture. The present review highlights the main results obtained in the field of hybrid and chimeric azine (especially pyridine, quinoline, phenanthroline, bypyridine, naphthyridine and their fused derivatives) derivatives presented in scientific literature from the last 10 years, with emphasis on antifungal activity of the mentioned compounds. A special attention was played to hybrid and chimeric azole-azine class, having in view the high antifungal potential of azoles.

Critical view on antimicrobial, antibiofilm and cytotoxic activities of quinazolin-4(3H)-one derived schiff bases and their Cu(II) complexes

A series of nine 2,3-disubstituted-quinazolin-4(3H)-one derived Schiff bases and their three Cu(II) complexes was prepared and tested for their antimicrobial activities against reference strains Staphylococcus aureus ATCC 29213 and Enterococcus faecalis ATCC 29212 and resistant clinical isolates of methicillin-resistant S. aureus (MRSA) and vancomycin-resistant E. faecalis (VRE). All the substances were tested in vitro against Mycobacterium tuberculosis H37Ra ATCC 25177, M. kansasii DSM 44162 and M. smegmatis ATCC 700084. While anti-enterococcal and antimycobacterial activities were insignificant, 3-[(E)-(2-hydroxy-5-nitrobenzylidene)amino]-2-(2-hydroxy-5-nitrophenyl)-2,3-dihydroquinazolin-4(1H)-one (SB3) and its Cu(II) complex (SB3-Cu) demonstrated bacteriostatic antistaphylococcal activity. In addition, both compounds, as well as the other two prepared complexes, showed antibiofilm activity, which resulted in a reduction of biofilm formation and eradication of mature S. aureus biofilm by 80% even at concentrations lower than the values of their minimum inhibitory concentrations. In addition, the compounds were tested for their cytotoxic effect on the human monocytic leukemia cell line THP-1. The antileukemic efficiency was improved by the preparation of Cu(II) complexes from the corresponding non-chelated Schiff base ligands.

Nitrogen-fused Heterocycles: Empowering Anticancer Drug Discovery

The worldwide impact of cancer is further compounded by the constraints of current anticancer medications, which frequently exhibit a lack of selectivity, raise safety apprehensions, result in significant adverse reactions, and encounter resistance mechanisms. The current situation highlights the pressing need to develop novel and more precise anticancer agents that prioritize safety and target specificity. Remarkably, more than 85% of drugs with physiological activity contain heterocyclic structures or at least one heteroatom. Nitrogen-containing heterocycles hold a significant position among these compounds, emerging as the most prevalent framework within the realm of heterocyclic chemistry. This article explores the medicinal chemistry behind these molecules, highlighting their potential as game-changing possibilities for anticancer medication development. The analysis highlights the inherent structural variety in nitrogen-containing heterocycles, revealing their potential to be customized for creating personalized anticancer medications. It also emphasizes the importance of computational techniques and studies on the relationships between structure and activity, providing a road map for rational medication design and optimization. Nitrogen- containing heterocycles are a promising new area of study in the fight against cancer, and this review summarises the state of the field so far. By utilizing their inherent characteristics and exploiting cooperative scientific investigations, these heterocyclic substances exhibit potential at the forefront of pioneering therapeutic approaches in combating the multifaceted obstacles posed by cancer.

Hybrids Diazine: Recent Advancements in Modern Antimicrobial Therapy

Nowadays, antimicrobial therapies have become a very challenging issue because of a large diversity of reasons such as antimicrobial resistance, over consumption and misuse of antimicrobial agents, etc. A modern, actual and very useful approach in antimicrobial therapy is represented by the use of hybrid drugs, especially combined five and six-membered ring azaheterocycles. In this review, we present an overview of the recent advanced data from the last five years in the field of hybrid diazine compounds with antimicrobial activity. In this respect, we highlight here essential data concerning the synthesis and antimicrobial activity of the main classes of diazine hybrids: pyridazine, pyrimidine, pyrazine, and their fused derivatives.

A Comprehensive Review on Potential Molecular Drug Targets for the Management of Alzheimer's Disease

Alzheimer's disease (AD) is an onset and incurable neurodegenerative disorder that has been linked to various genetic, environmental, and lifestyle factors. Recent research has revealed several potential targets for drug development, such as the prevention of Aβ production and removal, prevention of tau hyperphosphorylation, and keeping neurons alive. Drugs that target numerous ADrelated variables have been developed, and early results are encouraging. This review provides a concise map of the different receptor signaling pathways associated with Alzheimer's Disease, as well as insight into drug design based on these pathways. It discusses the molecular mechanisms of AD pathogenesis, such as oxidative stress, aging, Aβ turnover, thiol groups, and mitochondrial activities, and their role in the disease. It also reviews the potential drug targets, in vivo active agents, and docking studies done in AD and provides prospects for future drug development. This review intends to provide more clarity on the molecular processes that occur in Alzheimer's patient's brains, which can be of use in diagnosing and preventing the condition.

The Effective Synthesis of New Benzoquinoline Derivatives as Small Molecules with Anticancer Activity

In this study, some novel benzo[c]quinoline derivatives were synthesized, their structural characteristics were described, and their in vitro anticancer efficacy was investigated. The synthesis involves an initial quaternization of the nitrogen atom from benzo[c]quinoline and then a [3+2] dipolar cycloaddition reaction of the in situ formed ylide. The effectiveness of synthesis using traditional thermal heating (TH) compared to microwave (MW) and ultrasound (US) irradiation was investigated in detail. The setup of a reaction under MW or US irradiation offers a number of additional benefits: higher yields, a reduction in the amount of solvent used compared to TH, a reduction in the reaction time from hours to minutes, and a reduction in the amount of energy consumed. The structure of all the obtained compounds was proved by several spectral techniques (FTIR, HRMS, and NMR). All benzo[c]quinoline derivatives (quaternary salts and cycloadducts) along with ten other benzo[f]quinoline derivatives (quaternary salts and cycloadducts), previously obtained, were tested in an in vitro single-dose anticancer experiment. The results demonstrated that the cycloadducts 5a-c and 6a-c exhibit stronger anticancer activity than quaternary salts 3a-c. The most active compound is compound 5a, with anticancer activity on most of the cell lines studied, while the second most active compound is 6c, showing significant lethality for the SR leukemia cell line (17%). Structure-activity relationship (SAR) correlations are also included in the study.

Synthesis and in-vitro anti-proliferative with antimicrobial activity of new coumarin containing heterocycles hybrids

A series of new coumarin-N-heterocyclic hybrids, coumarin-quinolines 7a-e, coumarin-acridines 10b,c and coumarin-neocryptolepines 13b,c were synthesized and evaluated for their anticancer and antimicrobial activities. The structures of all synthesized hybrids were confirmed by FT-IR, 1H-NMR, 13C-NMR, and MS spectrometry. The anti-proliferative activity of hybrids 7a-e, 10c and 13c were bio-evaluated using MTT-assay against colon (CaCo-2), lung (A549), breast (MDA-MB-231), and hepatocellular carcinoma (HepG-2) human cancer cell lines using doxorubicin as a reference drug. The results demonstrated that, all hybrids displayed moderate to good anti-proliferative activity against the cell lines. The most active hybrids were 7a-d and 10c against CaCo-2 cancer cell line with IC50: 57.1, 52.78, 57.29, 51.95 and 56.74 µM, and selectivity index 1.38, 1.76, 2.6, 1.96 and 0.77; respectively. While, 7a,d were potent against A549 cancer cell line with IC50: 51.72, 54.8 µM and selectivity index 1.5, 0.67; respectively. Moreover, 7c showed the most potency against MDA-MB-231 cancer cell line with IC50: 50.96 µM and selectivity index 2.20. Interestingly, docking results revealed that binding energy of the current compounds showed marked affinity values ranging from -6.54 to -5.56 kcal with interactions with the reported key amino acid SER 79. Furthermore, the antimicrobial activity of the synthesized hybrids 7a-e, 10b,c, 13b and 13c were evaluated against Gram-positive and Gram-negative bacterial and fungal strains. The hybrids 10b, 13b, 10c, and 13c exhibited broad-spectrum antibacterial activity against E.coli, S. mutans, and S. aureus with MIC from 3.2 to 66 µM, this hybrids also displayed antifungal activity against C. albicans with MIC values ranging from 0.0011 to 29.5 µM. In-silico investigation of the pharmacokinetic properties indicated that tested hybrids had high GI absorption, low Blood Brain Barrier (BBB) permeability in addition to cell membrane penetrability.

Deciphering the Mechanism of MRSA Targeting Copper(II) Complexes of NN2 Pincer-Type Ligands

WHO lists AMR as one of the top ten global public health issues. Therefore, constant effort is needed to develop more efficient antimicrobial drugs. As a result, earth-abundant transition-metal complexes have emerged as an excellent solution. In this regard, new aminoquinoline-based copper(II) pincer complexes 1-3 were designed, synthesized, and characterized by modern spectroscopic techniques. It is worth mentioning that, at the highest concentration (1024 μg/mL) of complexes (1-3), the hemolysis was found to be <15%, implying their less toxicity. Further, the complexes effectively interfered with the growth of Gram positive MRSA and the fungus Candida albicans. Among them, complex 2 was promising (MIC = 16 μg/mL) against MRSA, which was better than the known antibacterial drug kanamycin (64 μg/mL) under identical conditions. The Alamar blue cell viability test and the MBC/MFC identified by spot assay were in accordance with MIC values. Moreover, the insilico studies explained the most probable mechanism of action as inhibition of cell wall biosynthesis and dysfunction of antibiotic sensing proteins. Similarly, the antifungal action might be due to the cell surface adhesion protein dysfunction by the complexes. Furthermore, we are expecting to draw these compounds for clinical applications.

Recent advances in triazoles as tyrosinase inhibitors

The tyrosinase enzyme, which is widely found in microorganisms, animals and plants, has a significant position in melanogenesis, plays an important role in undesirable browning of fruits and vegetables, antibiotic resistance, skin pigment formation, sclerotization of cuticle, neurodegeneration, etc. Therefore, with the wide potential application fields of tyrosinase in food, agriculture, cosmetics and pharmaceutical industries, which has become the target enzyme for the development of therapeutic agents such as antibrowning, anticancer, antibacterial, skin whitening, insecticides, etc., a large number of synthetic tyrosinase inhibitors have been widely reported in recent years. The triazole ring, which has a broad spectrum of biological action, is of increasing interest in the synthesis of new tyrosinase inhibitors. In this review, tyrosinase inhibition effects, structure-activity relationships, enzyme inhibition kinetics and mechanisms of action of 1,2,3- or 1,2,4-triazole derivatives were investigated. The data gathered is anticipated to supply rational guidance and an influential strategy for the development of novel, potent and safe tyrosinase inhibitors for better practical application in the future.

Ultrasound assisted synthesis of hybrid quinoline anchored with 4-R-benzenesulfonamide moiety with potential antimicrobial activity

We present in this paper a direct and efficient study regarding synthesis and spectral characterization of three series of hybrid quinoline anchored with 4-R-benzenesulfonamide moiety, with potential antimicrobial activity, by using ultrasound (US) irradiation and conventional methods (CV). The synthesis pathway is efficient and direct, in two steps: an initial N-acylation of 8-aminoquinoline followed by metal complexation with variously M2+ metals (Cd2+, Co2+, Cu2+, Ni2+, Pd2+, Zn2+). For both type of reactions, N-acylation and complexation, under US irradiations the synthesis have some undeniable advantages: the most relevant being the higher yields, a dramatically decrease for reaction time (with about 150 (one hundred fifty) folds for complexation) comparative with conventional methods (CV) (therefore the spent energy decrease in the same way), a decrease of the amount of used solvents. Taking into account the above considerations these reactions setup could be appreciated as eco-friendly. The structures of the obtained hybrid quinoline - sulfonamide complexes (HQBSM) were determined by elemental analysis and by using spectral investigations: FT-IR, NMR experiments, and X-ray diffraction (in three cases). The FT-IR and NMR spectra of complexes show a similar spectroscopic pattern for all complexes and fully confirm the proposed structures. The X-ray spectra analyses prove without doubts the structure of metal complexes, indicating that their structure depends essentially by two factors: the nature of metal and the nature of sulfonamide-quinoline moieties. Complexes containing 4-methoxy-benzoyl moiety and Zn2+ (e.g. 6a) are tetra-coordinated while in the Ni2+ complex (e.g. 6e) the metallic ion forms a distorted square-based bi-pyramid. In the complexes containing 4-nitro-benzoyl moiety and Cd2+ (e.g. 5d) the metallic ion forms a triangular bipyramid. The antibacterial and antifungal assay reveal that only hybrid HQBSM complex (4e) (with 4-chlorophenyl moiety and Ni2+ in molecule) have a significant antibacterial activity.

Novel 1,2,3-Triazole-Containing Quinoline-Benzimidazole Hybrids: Synthesis, Antiproliferative Activity, In Silico ADME Predictions, and Docking

The newly synthesized quinoline-benzimidazole hybrids containing two types of triazole-methyl-phenoxy linkers were characterized via NMR and elemental analysis. Additional derivatization was achieved by introducing bromine at the C-2 position of the phenoxy core. These novel hybrids were tested for their effects on the growth of the non-tumor cell line MRC-5 (human fetal lung fibroblasts), leukemia and lymphoma cell lines: Hut78, THP-1 and HL-60, and carcinoma cell lines: HeLa and CaCo-2. The results obtained, presented as the concentration that achieves 50% inhibition of cell growth (IC50 value), show that the compounds tested affect tumor cell growth differently depending on the cell line and the dose applied (IC50 ranged from 0.2 to >100 µM). The quinoline-benzimidazole hybrids tested, including 7-chloro-4-(4-{[4-(5-methoxy-1H-1,3-benzo[d]imidazol-2-yl)phenoxy]methyl}-1H-1,2,3-triazol-1-yl)quinoline 9c, 2-(3-bromo-4-{[1-(7-chloroquinolin-4-yl)-1H-1,2,3-triazol-4-yl]methoxy}phenyl)-N-propyl-1H-benzo[d]imidazol-5-carboximidamide trihydrochloride 10e, 2-{4-[(1-{2-[(7-chloroquinolin-4-yl)amino]ethyl}-1H-1,2,3-triazol-4-yl)methoxy]phenyl}-N-propyl-1H-benzo[d]imidazol-5-carboximidamide trihydrochloride 14e and 2-{3-bromo-4-[(1-{2-[(7-chloroquinolin-4-yl)amino]ethyl}-1H-1,2,3-triazol-4-yl)methoxy]phenyl}-N-propyl-1H-benzo[d]imidazol-5-carboximidamide trihydrochloride 15e, arrested the cell cycle of lymphoma (HuT78) cells. The calculated ADMET properties showed that the synthesized compounds violated at most two of Lipinski's rules, making them potential drug candidates, but mainly for parenteral use due to low gastrointestinal absorption. The quinoline-benzimidazole hybrid 14e, which was shown to be a potent and selective inhibitor of lymphoma cell line growth, obtained the highest binding energy (-140.44 kcal/mol), by docking to the TAO2 kinase domain (PDB: 2GCD).

Novel antimicrobial iodo-dihydro-pyrrole-2-one compounds

Aim: A series of new hybrid molecules with two iodine atoms on the sides were synthesized. Methods: A one-pot, two-component method with trifluoroacetic acid as an effective catalyst to obtain dihydro-pyrrol-2-one compounds was developed. Short reaction times, a cheap catalyst, high yields and clean work-up are benefits of this method. Results: The chemical structures of the newly synthesized compounds were verified through spectroscopic techniques. Their antimicrobial activity against Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans was tested in vitro. Conclusion: NC- and OH- radicals confer broad-spectrum antimicrobial activity, including against Gram-positive and Gram-negative bacteria and yeasts. Compounds 3g >7 and >9 were most active on the two bacterial species, while 3l >9 and >3i were most active against the fungal strain.

Anti-proliferative activity of nitroquinolone fused acylhydrazones as non-small cell human lung cancer agents

A new series of 8-nitroquinolone-based aromatic heterocyclic acyl hydrazones have been synthesised and characterised through various spectroscopic techniques. They were theoretically examined for molecular docking with various proteins related to the apoptosis of the non-small cell lung cancer cell line A549. The results indicate that the possible modes of interaction of all the synthesised compounds are compatible for use as anti-proliferative drugs. Also, the drug-likeness of the compounds was examined through theoretical ADMET analysis, which indicated good gastrointestinal absorption as well as low toxicity. Selected compounds were evaluated for their in vitro anti-cancer activity using A549, MCF-7 and HeLa cell lines through an MTT assay to determine cytotoxicity. Compounds 3c, 3a and 11c exhibited significant cytotoxicity towards A549 cells in the order of 3c (15.3 ± 0.7) > 3a (15.8 ± 0.1) > 11c (17.1 ± 0.2), whereas all the compounds show insignificant toxicity on normal human embryonic kidney cells up to a concentration of 200 μM. The best compounds among the series (3c and 11c) were chosen for further detection of apoptosis through fluorescence microscopic techniques using AO/EtBr and DAPI. The reduced DNA synthesis during the cell cycle was also investigated through flow cytometric techniques. The results indicate that the compounds possess significant anticancer properties due to the activation of the mitochondrial mediated intrinsic pathway.

Benzoquinoline Derivatives: An Attractive Approach to Newly Small Molecules with Anticancer Activity

This study presents the synthesis, structural characterization, and in vitro evaluation of anticancer activity of some newly benzo[f]quinoline derivatives. The synthesis is facile and efficient, involving two steps: quaternization of nitrogen heterocycle followed by a [3+2] dipolar cycloaddition reaction. The synthesized compounds were characterized by FTIR, NMR, and X-ray diffraction on monocrystal in the case of compounds 6c and 7c. An in vitro single-dose anticancer assay of eighteen benzo[f]quinoline compounds, quaternary salts, and cycloadducts, was performed. The results showed that the most active compounds were quaternary salts 3d and 3f with aromatic R substituents. Quaternary salt 3d revealed non-selective activity against all types of cancer cells, while salt 3f exhibited a highly selective activity against leukemia cells. Compound 3d also presented remarkable cytotoxic efficiency against four distinct types of cancer cells-namely, non-small cell lung cancer HOP-92, melanoma LOX IMVI, melanoma SK-MEL-5, and breast cancer MDA-MB-468. Compound 3f was selected for five-dose screening. The study also includes SAR correlations.