Synthesis, molecular docking studies and biological evaluation of potent coumarin–carbonodithioate hybrids via microwave irradiation

Novel 3-phenyl-1- (alkylphenyl)-9-oxa-4-azaphenanthren-10-ones as inhibitors of some enzymes: synthesis, characterization, biological evaluation and molecular docking studies

A series of novel 3-phenyl-1-(alkylphenyl)-9-oxa-4-azaphenanthren-10-ones and (E)-1-phenyl-3-(aryl)prop-2-en-1-ones were synthesized and characterized by IR, 1H NMR, 13C spectroscopy and elemental analysis. The synthesized Compounds 5a-f were subjected to molecular docking simulation with three proteins, namely, tyrosyl-tRNA synthetase, heme oxygenase 1 and acetylcholinesterase to evaluate the antibacterial, antioxidant and acetylcholinesterase inhibition, respectively. Moreover, the docked poses of all compounds inside the proteins were subjected to further dynamic simulation through the calculation of the binding free energy using MM-GBSA analysis. Compound 5d exhibits high potential inhibition against antibacterial, antioxidant and acetylcholinesterase activities. Compounds 3d, 3f, 5a and 5d recorded an important scavenging activity in DPPH and ABTS assays. Investigation of the anti-acetylcholinesterase activity of the synthesized compounds showed that Compounds 5a and 3d are the most potent inhibitors against AchE, with percent inhibition values of 38 and 30%, respectively.Communicated by Ramaswamy H. Sarma.

Molecular Insights into Coumarin Analogues as Antimicrobial Agents: Recent Developments in Drug Discovery

Simple Summary

Coumarins are a large family of benzopyrones, and more than 1300 coumarins have been reported to date. Natural, as well as synthetic, coumarins have demonstrated a diverse activity spectrum. On the other hand, the demands of the current health scenario witnessing morbidity and mortality due to microbial infections and multidrug-resistant bacterial strains, the well-reported phytochemical coumarin can be of interest. Some of the well-reported coumarin analogues as antimicrobial agents include β-lactum derivatives, coumarin-based 1,2,3-triazole compounds, the miconazole analogue, coumarin-substituted pyrazole hybrids, pyranocoumarin, coumarin−sulphonamide hybrids, pyranocoumarins, coumarin−sulphonamide derivatives, chromenylpyrazoles candidates, 3-amidocoumarins analogues, uracil−coumarin hybrids, indolinedione−coumarin hybrids, coumarin−imidazole hybrids, coumarin-fused pyrazolones and methyl thiazole derivatives, coumarin−theophylline hybrids, etc. In the present review, several methods for the synthesis of coumarin derivatives as antimicrobial agents are reported, along with structure−activity relationship (SAR) studies focusing on the developments reported since 2016.

Abstract

A major global health risk has been witnessed with the development of drug-resistant bacteria and multidrug-resistant pathogens linked to significant mortality. Coumarins are heterocyclic compounds belonging to the benzophenone class enriched in different plants. Coumarins and their derivatives have a wide range of biological activity, including antibacterial, anticoagulant, antioxidant, anti-inflammatory, antiviral, antitumour, and enzyme inhibitory effects. In the past few years, attempts have been reported towards the optimization, synthesis, and evaluation of novel coumarin analogues as antimicrobial agents. Several coumarin-based antibiotic hybrids have been developed, and the majority of them were reported to exhibit potential antibacterial effects. In the present work, studies reported from 2016 to 2020 about antimicrobial coumarin analogues are the focus. The diverse biological spectrum of coumarins can be attributed to their free radical scavenging abilities. In addition to various synthetic strategies developed, some of the structural features include a heterocyclic ring with electron-withdrawing/donating groups conjugated with the coumarin nucleus. The suggested structure−activity relationship (SAR) can provide insight into how coumarin hybrids can be rationally improved against multidrug-resistant bacteria. The present work demonstrates molecular insights for coumarin derivatives having antimicrobial properties from the recent past. The detailed SAR outcomes will benefit towards leading optimization during the discovery and development of novel antimicrobial therapeutics.

Pharmacological report of recently designed multifunctional coumarin and coumarin-heterocycle derivatives

Coumarin is a naturally available molecule and has been identified as a potent pharmacophore due to its pharmacological activity. Because of this, coumarin has been exploited synthetically to prepare a wide range of derivatives. In fact, most coumarin derivatives have been found to be less toxic, which is the most essential property for a drug molecule. Such molecules are being prepared for therapeutic use as broad-spectrum pharmacological agents. Microbial diseases including viral diseases have become very common and are responsible for many deaths worldwide. In particular, microbial drug resistance is a problem that needs to be tackled in an effective manner. Also, for Alzheimer's disease, which affects most elderly persons, no efficient chemotherapy exists. In addition, although diabetes, a metabolic syndrome, can be treated with many drugs, there is no complete cure. Thus, more potent antidiabetic agents are required for the management of diabetes. Likewise, for the treatment of a wide range of ailments caused by microbes, genetic factors, or lifestyle-related factors, an efficient drug regimen is needed. In view of this, coumarin derivatives are designed and evaluated. Here, coumarin derivatives that have been reported recently are compiled, classified and evaluated critically. This study briefly takes the structure-activity relationship into consideration and suggests the next suitable step. With a focus on the most potent molecules, the pharmacological activity of the evaluated molecules is described.

Medicinal applications of coumarins bearing azetidinone and thiazolidinone moieties

Coumarins (2H-chromen-2-ones), also known as benzopyran-2-ones, are a family of naturally occurring heterocyclic ring systems that contain a lactone moiety. Coumarins exhibit a wide range of well-studied pharmacological properties. Over the last few decades, as a result of advances in diverse oriented synthetic routes, physicochemical properties and numerous biological activities, coumarins have become globally studied molecules from various synthetic and medicinal chemists. Recently, several bioactive coumarins bearing azetidinone and thiazolidinone moieties have been found to display a range of therapeutic characteristics, including antimicrobial, anticancer, antidiabetic and anti-inflammatory properties. This review offers a brief description of the synthetic methodologies, known bioactivity and structure-activity relationships of coumarins bearing azetidinones and thiazolidinones.

Effect of organic solvents on solvatochromic, fluorescence, and electrochemical properties of synthesized thiazolylcoumarin derivatives

In this present investigation, thiazolylcoumarin derivatives (5a-5k) were synthesized from thiosemicarbazide, ethyl acetoacetate, and naphthaldehyde through a multistep route. The formation of thiazolylcoumarin derivatives with bioactive scaffolds was confirmed through nuclear magnetic resonance spectroscopy. A solvatochromic study of synthesized thiazolylcoumarin derivatives was carried out using ultraviolet-visible methods for dimethylformamide (DMF), ethyl acetate, and ethanol solvents. The redox behaviour of as-synthesized thiazolylcoumarin derivatives (5a-5k) was examined in dimethyl sulphoxide by conducting an electrochemical study. Fluorescence properties of thiazolylcoumarin derivatives were studied in DMF, ethanol, and ethyl acetate to visualize the solvent effect on the emitting ability of thiazolylcoumarin derivatives.

In silico molecular docking studies and MM/GBSA analysis of coumarin-carbonodithioate hybrid derivatives divulge the anticancer potential against breast cancer

Background

There are many biomarkers associated with breast cancer. Higher expression of PIK3CA (Phosphoinositide 3-kinase Cα), in its upregulated form, is associated with Hr+ and Her2− breast cancer; therefore, many drugs were synthesized against this protein to treat breast cancer patients. FDA recently approved that the drug alpelisib also inhibits PI3KCα (PDB ID-5DXT) in BC patients with Hr+ and Her2−. In present study, we have exploited fourteen coumarin-carbonodithioate derivatives and alpelisib against this protein along with eighteen others which are responsible for causing BC through computational analysis. We have used Schrödinger Maestro 11.2 version for our in silico docking study, and to calculate relative binding energies of ligands, we used prime MM-GBSA module.

Result

Docking study revealed that among all fourteen compounds, 2f, 2a, 2d, and 2e showed the highest G score than the alpelisib and coumarin against PI3KCα with − 9.3, − 9.0, − 9.0 and − 9.1 kcal/mol respectively, along with individual G score of alpelisib (− 8.9) and coumarin (− 7.9). Prime MM-GBSA analysis gave the relative binding energies of alpelisib, 2f, and 2e with − 19.94864535, − 18.63076296 and − 13.07341286 kcal/mol sequentially.

Conclusion

This study provides an insight into the coumarin-carbonodithioate derivatives that could act as inhibitors of PI3KCα like alpelisib. Further prime MM-GBSA study revealed ligand binding energies and ligands strain energies.

In vitro and in silico analysis of L. donovani enoyl acyl carrier protein reductase - A possible drug target

The emergence of increased resistance to the available drugs has created a situation that demands to find out more specific molecular drug targets for Leishmaniasis. The enoyl acyl carrier protein reductase (ENR), a regulatory enzyme in type II fatty acid synthesis, was confirmed as a novel drug target and triclosan as its specific inhibitor in many microorganisms. In this study, the triclosan was tested for the leishmanicidal property against Leishmania donovani (L. donovani) and the results of in vitro and ex vivo drug assays on promastigotes and amastigotes showed that triclosan possessed antileishmanial activity with a half minimal inhibitory concentration (IC₅₀) of 30 µM. Consequently, adopting in silico approach, we have tested the triclosan's ability to bind with the L. donovani enoyl acyl carrier protein reductase (LdENR). The 3D structure of LdENR was modelled, triclosan and cofactors were docked in LdENR model and molecular dynamic simulations were performed to observe the protein-ligands interactions, stability, compactness and binding energy calculation of the ligands-LdENR complexes. The observation showed that triclosan stably interacted with LdENR in presence of both the cofactors (NADPH and NADH), however, simulation results favor NADH as a preferred co-factor for LdENR. These results support that the reduction of L. donovani growth in the in vitro and ex vivo drug assays may be due to the interaction of triclosan with LdENR, which should be confirmed through enzymatic assays. The results of this study suggest that LdENR could be a potential drug target and triclosan as a lead for Leishmaniasis.Communicated by Ramaswamy H. Sarma.

Monocarbonyl Curcumin-Based Molecular Hybrids as Potent Antibacterial Agents

Keeping in view various pharmacological attributes of curcumin, coumarin, and isatin derivatives, triazole-tethered monocarbonyl curcumin-coumarin and curcumin-isatin molecular hybrids have been synthesized and evaluated for their antibacterial potential against Gram-positive (Enterococcus faecalis and Staphylococcus aureus) and Gram-negative (Pseudomonas aeruginosa and Escherichia coli) human pathogenic bacterial strains. Among all hybrid molecules, A-4 and B-38 showed the most potent antibacterial activity with inhibition zones of 29 and 31 mm along with MIC values of 12.50 and 6.25 μg/mL, respectively. Structure-activity relationship that emerged from biological data revealed that the two-carbon alkyl chain between triazole and coumarin/isatin moiety is well tolerable for the activity. Bromo substitution at the fifth position of isatin, para-cholo substitution in the case of curcumin-isatin, and para-methoxy in the case of curcumin-coumarin hybrids on ring A of curcumin are most suitable groups for the antibacterial activity. Various types of binding interactions of A-4 and B-38 within the active site of dihydrofolate reductase (DHFR) of S. aureus are also streamlined by molecular modeling studies, suggesting their capability in completely blocking DHFR.

Design, Synthesis, Antimicrobial Evaluation, and Molecular Modeling Studies of Novel Indolinedione-Coumarin Molecular Hybrids

Keeping in view various pharmacological attributes of indole and coumarin derivatives, a new series of indolindione-coumarin molecular hybrids was rationally designed and synthesized. All synthesized hybrid molecules were evaluated for their antimicrobial potential against Gram-negative bacterial strains (Escherichia coli and Salmonella enterica), Gram-positive bacterial strains (Staphylococcus aureus and Mycobacterium smegmatis), and four fungal strains (Candida albicans, Alternaria mali, Penicillium sp., and Fusarium oxysporum) by using the agar gel diffusion method. Among all synthetics, compounds K-1 and K-2 were found to be the best antimicrobial agents with the minimum inhibitory concentration values of 30 and 312 μg/mL, against Penicillium sp. and S. aureus, respectively. The biological data revealed some interesting facts about the structure-activity relationship which state that the electronic environment on the indolinedione moiety and carbon chain length between indolinedione and triazole moieties considerably affect the antimicrobial potential of the synthesized hybrids. Various types of binding interactions of K-2 within the active site of S. aureus dihydrofolate reductase were also streamlined by molecular modeling studies, which revealed the possible mechanism for potent antibacterial activity of the compound.

Microwave assisted synthesis of coumarin-purine derivatives: An approach to in vitro anti-oxidant, DNA cleavage, crystal structure, DFT studies and Hirshfeld surface analysis

An easy and efficient microwave-assisted protocol has been developed for the synthesis of coumarin-purine hybrids (3a-3j). The newly constructed 1,3-dimethyl-7-((substituted)-2-oxo-2H-chromen-4-yl)methyl)-1H-purine-2,6(3H,7H)-dione derivatives were evaluated for their in vitro antioxidant activity by DPPH free radical-scavenging ability assay and DNA cleavage by using calf thymus. The compound 3i, shows the most excellent DPPH scavenging activity with a –OH substitution at C7 of coumarin ring. In addition, the structure of compound 3f, has been elucidated using single crystal X-ray diffraction technique. Theoretical calculations (DFT) were carried out using Gaussian09 program package and B3LYP correlation function. Full geometry optimization were carried out using 6-311G++(d, p) basis set and the frontier orbital energy were presented. Hirshfeld surface analysis was used for the intermolecular interactions in the crystal structure. The experimental result of the compound 3f has been compared with the theoretical results and it was found that the experimental data are in a good agreement with the calculated values.

Synthesis of some novel quinazolin-4(3H)-one hybrid molecules as potent urease inhibitors

A new series of quinazolinone hybrid molecules containing coumarin, furan, 1,2,4-triazole and 1,2,4-thiadiazole rings was designed, synthesized, and screened for their urease inhibition activities. All newly synthesized compounds showed outstanding urease inhibitory potentials with IC₅₀ values ranging between 1.26 ± 0.07 and 7.35 ± 0.31 μg/mL. Among the series, coumarin derivatives (10a-d) exhibited the best inhibitory effect against urease in the range of IC₅₀  = 1.26 ± 0.07 to 1.82 ± 0.10 μg/mL, when compared to standard urease inhibitors such as acetohydroxamic acid and thiourea (IC₅₀  = 21.05 ± 0.96 and 15.08 ± 0.71 μg/mL, respectively). Molecular docking studies were also performed to analyze the binding mode of compound 10b, and supported the experimental results.