Identification of quinoline-chalcones and heterocyclic chalcone-appended quinolines as broad-spectrum pharmacological agents

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.

Identification of potent BRD4-BD1 inhibitors using classical and steered molecular dynamics based free energy analysis

In the present work a combination of traditional and steered molecular dynamics based techniques were employed to identify potential inhibitors against the human BRD4 protein (BRD4- BD1); an established drug target for multiple illnesses including various malignancies. Quinoline derivatives that were synthesized in-house were tested for their potential as new BRD4-BD1 inhibitors. Initially molecular docking experiments were performed to determine the binding poses of BRD4-BD1 inhibitors. To learn more about the thermodynamics of inhibitor binding to the BRD4-BD1 active site, the Molecular Mechanics Poisson-Boltzmann Surface Area (MM-PBSA) free energy calculations were conducted afterwards. The findings of the MM-PBSA analysis were further reinforced by performing steered umbrella sampling simulations which revealed crucial details about the binding/unbinding process of the most potent quinoline derivatives at the BRD4-BD1 active site. We report a novel quinoline derivative which can be developed into a fully functional BRD4-BD1 inhibitor after experimental validation. The identified compound (4 g) shows better properties than the standard BRD4-BD1 inhibitors considered in the study. The study also highlights the crucial role of Gln78, Phe79, Trp81, Pro82, Phe83, Gln84, Gln85, Val87, Leu92, Leu94, Tyr97, Met105, Cys136, Asn140, Ile146 and Met149 in inhibitor binding. The study provides a possible lead candidate and key amino acids involved in inhibitor recognition and binding at the active site of BRD4-BD1 protein. The findings might be of significance to medicinal chemists involved in the development of potent BRD4-BD1 inhibitors.

Synthesis and Pharmacological Activities of Chalcone and Its Derivatives Bearing N-Heterocyclic Scaffolds: A Review

The incorporation of heterocyclic moieties into the standard chemical structure with a biologically active scaffold has become of crucial practice for the construction of pharmacologically potent candidates in the drug arena. Currently, numerous kinds of chalcones and their derivatives have been synthesized using the incorporation of heterocyclic scaffolds, especially chalcones bearing heterocyclic moieties that display improved efficiency and potential for drug production in pharmaceutical sectors. The current Review focuses on recent advances in the synthetic approaches and pharmacological activities such as antibacterial, antifungal, antitubercular, antioxidant, antimalarial, anticancer, anti-inflammatory, antigiardial, and antifilarial activities of chalcone derivatives incorporating N-heterocyclic moieties at either the A-ring or B-ring.

Design, synthesis, molecular dynamics simulation, MM/GBSA studies and kinesin spindle protein inhibitory evaluation of some 4-aminoquinoline hybrids

The discovery of novel chemotherapeutic agents is always challenging for researchers in industry and academia. Among the recent promising anticancer therapeutic targets, an important modulatory factor in mitosis is the expression of the kinesin family motor protein (Eg5). In terms of chemotherapy treatment, mitosis has gained significant attention due to its role as one of the biological processes that can be intervened in it. This study was undertaken to design, synthesise and evaluation of 4-aminoquinoline hybrid compounds as potential Eg5 inhibitors. Based on data collected from Malachite green and steady state ATPase assays, it has been determined that compounds such as 6c, 6d, 6g, and 6h are sensitive to Eg5 inhibition. In special mention, compounds 4 and 6c showed promising inhibitory activity in Malachite green assay with IC₅₀ values of 2.32 ± 0.23 µM and 1.97 ± 0.23 µM respectively. Compound 4 showed favourable inhibitory potential Steady state ATPase Assay with IC₅₀ value of 5.39 ± 1.39 µM. We performed molecular docking, MM/GBSA calculations, and molecular dynamic simulations to evaluate the interactions between ligands and the binding site of the kinesin spindle protein to evaluate the functional consequences of these interactions. As a result of these findings, it can be concluded that these 4-amioquinoline Schiff's base hybrids may prove to be promising candidates for development as novel inhibitors of Eg5. Further in-vivo research in this area is required.

A three-step pathway from (2-aminophenyl)chalcones to novel styrylquinoline-chalcone hybrids: synthesis and spectroscopic and structural characterization of three examples

Three new styrylquinoline-chalcone hybrids have been synthesized using a three-step pathway starting with Friedländer cyclocondensation between (2-aminophenyl)chalcones and acetone to give 2-methyl-4-styrylquinolines, followed by selective oxidation to the 2-formyl analogues, and finally Claisen-Schmidt condensation between the formyl intermediates and 1-acetylnaphthalene. All intermediates and the final products have been fully characterized by IR and 1H/13C NMR spectroscopy, and by high-resolution mass spectrometry, and the three products have been characterized by single-crystal X-ray diffraction. The molecular conformations of (E)-3-{4-[(E)-2-phenylethenyl]quinolin-2-yl}-1-(naphthalen-1-yl)prop-2-en-1-one, C30H21NO, (IVa), and (E)-3-{4-[(E)-2-(4-fluorophenyl)ethenyl]quinolin-2-yl}-1-(naphthalen-1-yl)prop-2-en-1-one, C30H20FNO, (IVb), are very similar. In each compound, the molecules are linked into a three-dimensional array by hydrogen bonds, of the C-H...O and C-H...N types in (IVa), and of the C-H...O and C-H...π types in (IVb), and by two independent π-π stacking interactions. By contrast, the conformation of the chalcone unit in (E)-3-{4-[(E)-2-(2-chlorophenyl)ethenyl]quinolin-2-yl}-1-(naphthalen-1-yl)prop-2-en-1-one, C30H20ClNO, (IVc), differs from those in (IVa) and (IVb). There are only weak hydrogen bonds in the structure of (IVc), but a single rather weak π-π stacking interaction links the molecules into chains. Comparisons are made with some related structures.

New quinoline-based triazole hybrid analogs as effective inhibitors of α-amylase and α-glucosidase: Preparation, in vitro evaluation, and molecular docking along with in silico studies

The 7-quinolinyl-bearing triazole analogs were synthesized (1d–19d) and further assessed in vitro for their inhibitory profile against α-amylase andα-glucosidase. The entire analogs showed a diverse range of activities having IC₅₀ values between 0.80 ± 0.05 µM to 40.20 ± 0.70 µM (α-amylase) and 1.20 ± 0.10 µM to 43.30 ± 0.80 µM (α-glucosidase) under the positive control of acarbose (IC₅₀ = 10.30 ± 0.20 µM) (IC₅₀ = 9.80 ± 0.20 µM) as the standard drug. Among the synthesized scaffolds, seven scaffolds 12d, 10d, 8d, 9d, 11d, 5d, and 14d showed excellent α-amylase and α-glucosidase inhibitory potentials with IC₅₀ values of 4.30 ± 0.10, 2.10 ± 0.10, 1.80 ± 0.10, 1.50 ± 0.10, 0.80 ± 0.05, 5.30 ± 0.20, and 6.40 ± 0.30 µM (against α-amylase) and 3.30 ± 0.10, 2.40 ± 0.10, 1.20 ± 0.10, 1.90 ± 0.10, 8.80 ± 0.20, 7.30 ± 0.40, and 5.50 ± 0.10 µM (against α-glucosidase), respectively, while the remaining 12 scaffolds 19d, 8d, 17d, 16d, 15d, 7d, 4d, 3d, 1d, 2d, 13d and 6 d showed less α-amylase and α-glucosidase inhibitory potentials than standard acarbose but still found to be active. Structure–activity connection studies also showed that scaffolds with electron-withdrawing groups like -Cl, -NO₂, and -F linked to the phenyl ring had higher inhibitory potentials for -amylase and -glucosidase than scaffolds with -OCH₃, -Br, and -CH₃ moieties. In order to better understand their binding sites, the powerful scaffolds 11d and 9d were also subjected to molecular docking studies. The results showed that these powerful analogs provide a number of important interactions with the active sites of both of these targeted enzymes, including conventional hydrogen bonding, pi–pi stacking, pi–sulfur, pi–anion, pi–pi, pi–sigma, T-shaped, and halogen (fluorine). Furthermore, various techniques (spectroscopic), including 1H, ¹³C-NMR, and HREI-MS mass, were used to explore the correct structure of newly afforded hybrid scaffolds based on quinoline-bearing triazole ring.