A series of hybrid of triazoloquinoxaline-chalcone derivatives 7a-k were designed, synthesized, fully characterized, and evaluated for their cytotoxic activity against three target cell lines: human breast adenocarcinoma (MCF-7), human colon carcinoma (HCT-116), and human hepatocellular carcinoma (HEPG-2). The preliminary results showed that some of these chalcones like 7b-c, and 7e-g exhibited significant antiproliferative effects against most of the cell lines, with selective or non-selective behavior, indicated by IC50 values in the 1.65 to 34.28 µM range. In order to investigate the mechanistic aspects of these active compounds, EGFR TK and tubulin inhibitory activities were measured as further biological assays. The EGFR TK assay results revealed that the derivatives 7a-c, 7e, and 7g could inhibit the EGFR TK in the submicromolar range (0.093 to 0.661 µM). Moreover, an antitubulin polymerization effect was noted for the active derivatives compared to the reference drug colchicine, with compounds 7e and 7g displaying 14.7 and 8.4 micromolar activity, respectively. Furthermore, a molecular docking study was carried out to explain the observed effects and the binding modes of these chalcones with the EGFR TK and tubulin targets.

https://www.mdpi.com/1420-3049/23/1/48/pdf

Design, Synthesis and Cytotoxic Evaluation of Novel Chalcone Derivatives Bearing Triazolo[4,3-a]-quinoxaline Moieties as Potent Anticancer Agents with Dual EGFR Kinase and Tubulin Polymerization Inhibitory Effects

Natural products are a source of many novel compounds with biological activity for the discovery of new pesticides and pharmaceuticals. Quinoxaline is a fused N-heterocycle in many natural products and synthetic compounds, and seven novel quinoxaline derivatives were designed and synthesized via three steps. Pesticidal activities of title quinoxaline derivatives were bioassayed. Most of these compounds had herbicidal, fungicidal, and insecticidal activities. The compounds 2-(6-methoxy-2-oxo-3-phenylquinoxalin-1(2H)-yl)acetonitrile (3f) and 1-allyl-6-methoxy-3-phenylquinoxalin-2(1H)-one (3g) were the most active herbicides and fungicides. Mode-of-action studies indicated that 3f is a protoprophyrinogen oxidase-inhibiting herbicide. Compound 3f also possessed broad-spectrum fungicidal activity against the plant pathogen Colletotrichum species. Some of these compounds also had insecticidal activity. Molecular docking and DFT analysis can potentially be used to design more active compounds.

Synthesis and Pesticidal Activities of New Quinoxalines

Epigenetic dysfunction has been widely implicated in several diseases especially cancers thus highlights the therapeutic potential for chemical interventions in this field. With rapid development of computational methodologies and high-performance computational resources, computer-aided drug design has emerged as a promising strategy to speed up epigenetic drug discovery. Herein, we make a brief overview of major computational methods reported in the literature including druggability prediction, virtual screening, homology modeling, scaffold hopping, pharmacophore modeling, molecular dynamics simulations, quantum chemistry calculation, and 3D quantitative structure activity relationship that have been successfully applied in the design and discovery of epi-drugs and epi-probes. Finally, we discuss about major limitations of current virtual drug design strategies in epigenetics drug discovery and future directions in this field.

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Computer-Aided Drug Design in Epigenetics

Alzheimer's disease (AD), one of the main causes of aged dementia, is a progressive and degenerative neurological disorder characterized by loss of cognition and memory. Although the symptomatic treatment of AD, particularly acetylcholinesterase inhibitors (AChEIs) based on the 'cholinergic hypothesis', has been successful in clinic, at present there is no cure for this disease. In this study, we designed compounds carrying benzimidazole and triazole rings on the same chemical skeleton so as to investigate their potential acetylcholinesterase and butyrylcholinesterase activity. Furthermore, molecular modeling study was performed to determine the binding mode of the best inhibitor to the AChE. Among them, compounds 3d and 3h, which featured 3,4-dihydroxy substitution at the phenyl ring and 5(6)-chloro substitution at the benzimidazole ring were found to be potent inhibitors of AChE. The inhibition kinetics of the two most active derivatives 3d and 3h were further studied. The kinetic displayed increasing slope and increasing intercept, which is consistent with a mixed inhibition. The IC50 and Ki values of 3d are 31.9 ± 0.1 nM and 26.2 nM, respectively. Compound 3h exhibited IC50 of 29.5 ± 1.2 nM and Ki of 24.8 nM. The above data compared favorably with data for donepezil (21.8 ± 0.9 nM) the reference compound in our study.

https://www.mdpi.com/1420-3049/24/5/861/pdf

Synthesis and AChE-Inhibitory Activity of New Benzimidazole Derivatives.

Urea transporter A (UT-A) isoforms encoded by the Slc14a2 gene are expressed in kidney tubule epithelial cells, where they facilitate urinary concentration. UT-A1 inhibition is predicted to produce a unique salt-sparing diuretic action in edema and hyponatremia. Here we report the discovery of 1,2,4-triazoloquinoxalines and the analysis of 37 synthesized analogues. The most potent compound, 8ay, containing 1,2,4-triazolo[4,3-a]quinoxaline-substituted benzenesulfonamide linked by an aryl ether, rapidly and reversibly inhibited UT-A1 urea transport by a noncompetitive mechanism with IC50 ≈ 150 nM; the IC50 was ∼2 μM for the related urea transporter UT-B encoded by the Slc14a1 gene. Molecular modeling suggested a putative binding site on the UT-A1 cytoplasmic domain. In vitro metabolism showing quinoxaline ring oxidation prompted the synthesis of metabolically stable 7,8-difluoroquinoxaline analogue 8bl, which when administered to rats produced marked diuresis and reduced urinary osmolality. 8bl has substant...

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Nanomolar-Potency 1,2,4-Triazoloquinoxaline Inhibitors of the Kidney Urea Transporter UT-A1.

Discovery of novel [1,2,4]triazolo[4,3-a]quinoxaline aminophenyl derivatives as BET inhibitors for cancer treatment.

Novel tacrine-pyridinium hybrid reactivators of organophosphorus-inhibited acetylcholinesterase: Synthesis, molecular docking, and in vitro reactivation study.

Jooyun Lee

Papers

Discovery of novel [1,2,4]triazolo[4,3-a]quinoxaline aminophenyl derivatives as BET inhibitors for cancer treatment.

Novel tacrine-pyridinium hybrid reactivators of organophosphorus-inhibited acetylcholinesterase: Synthesis, molecular docking, and in vitro reactivation study.