Hetero-annulated coumarins as new AChE/BuChE inhibitors: synthesis and biological evaluation

Novel quinazoline-chromene hybrids as anticancer agents: Synthesis, biological activity, molecular docking, dynamics and ADME studies

In this study, new quinazoline-chromene hybrid compounds were synthesized. The cytotoxic effects on cell viability of the hybrid compounds were tested against A549 human lung adenocarcinoma and BEAS-2B healthy bronchial epithelial cell lines in vitro. In addition, the ability of the active compounds to inhibit cell migration was tested. Molecular docking studies were performed to evaluate the ligand-protein interactions, and molecular dynamics simulations were performed to determine the interactions and stability of ligand-protein complexes. In silico absorption, distribution, metabolism, and excretion (ADME) studies were conducted to estimate the drug-likeness of the compounds. Compounds 4 (IC50  = 51.2 µM) and 5 (IC50  = 44.2 µM) were found to be the most active agents against A549 cells. They are found to be more selective against A549 cells than the reference drug doxorubicin. They also have the ability to significantly inhibit cell migration. They have the best docking scores against epidermal growth factor receptor (EGFR) (-11.300 and -11.226 kcal/mol) and vascular endothelial growth factor receptor 2 (VEGFR2) (-10.987 and -11.247 kcal/mol), respectively. In MD simulations, compounds 4 and 5 have strong hydrogen bond interactions above 80% of simulation times and showed a low ligand root mean square deviation (RMSD) around 2 Å. According to the ADME analysis, compounds 4 and 5 exhibit excellent drug-likeness and pharmacokinetic characteristics.

An Overview of Coumarin as a Versatile and Readily Accessible Scaffold with Broad-Ranging Biological Activities

Privileged structures have been widely used as an effective template for the research and discovery of high value chemicals. Coumarin is a simple scaffold widespread in Nature and it can be found in a considerable number of plants as well as in some fungi and bacteria. In the last years, these natural compounds have been gaining an increasing attention from the scientific community for their wide range of biological activities, mainly due to their ability to interact with diverse enzymes and receptors in living organisms. In addition, coumarin nucleus has proved to be easily synthetized and decorated, giving the possibility of designing new coumarin-based compounds and investigating their potential in the treatment of various diseases. The versatility of coumarin scaffold finds applications not only in medicinal chemistry but also in the agrochemical field as well as in the cosmetic and fragrances industry. This review is intended to be a critical overview on coumarins, comprehensive of natural sources, metabolites, biological evaluations and synthetic approaches.

15-Hydroxygermacranolides as Sources of Structural Diversity: Synthesis of Sesquiterpene Lactones by Cyclization and Rearrangement Reactions. Experimental and DFT Study

A study on the electrophile-induced rearrangement of two 15-hydroxygermacranolides, salonitenolide and artemisiifolin, was carried out. These compounds underwent electrophilic intramolecular cyclizations or acid-mediated rearrangements to give sesquiterpene lactones with different skeletons such as eudesmanolides, guaianolides, amorphanolides, or other germacranolides. The cyclization that gives guaianolides can be considered a biomimetic route to this type of sesquiterpene lactones. The use of acetone as a solvent changes the reactivity of the two starting germacranolides to the acid catalysts, with a 4,15-diol acetonide being the main product obtained. The δ-amorphenolide obtained by intramolecular cyclization of this acetonide is a valuable intermediate for accessing the antimalarials artemisinin and its derivatives. Mechanistic proposals for the transformations are raised, and to provide support them, quantum chemical calculations [DFT B3LYP/6-31+G(d,p) level] were undertaken.

New tacrine-derived AChE/BuChE inhibitors: Synthesis and biological evaluation of 5-amino-2-phenyl-4H-pyrano[2,3-b]quinoline-3-carboxylates

A series of poly-functionalized tacrine-derived compounds namely 5-amino-2-phenyl-4H-pyrano[2,3-b]quinoline-3-carboxylates were designed and synthesized as cholinesterases inhibitors. The in vitro inhibition assay against AChE and BuChE demonstrated that most of compounds had potent AChE inhibitory with reserving potential of BuChE inhibition. Among them, compound 6i bearing a 4-(3-bromophenyl) moiety showed the most potent activity against AChE/BuChE (IC₅₀s values of 0.069 and 1.35 μM, respectively). The anti-AChE activity of 6i was five times more than that of tacrine. The SAR study revealed that chloro/bromo substituent at ortho or meta position of the 4-phenyl ring can improve the anticholinesterase activity.