Synthesis, Docking Study of Some Novel Chromeno[4',3'-B]Pyrano[6,5-D]Pyrimidine Derivatives Against Covid-19 Main Protease (MPRO) (6LU7, 6M03).

AIMS: In this work, some new chromeno[4',3'-b]pyrano[6,5-d]pyrimidines,3-amino and 3-methyl-5-aryl-4-imino-5(H)-chromeno[4',3'-b]pyrano[6,5-d]pyrimidine-6-ones derivatives were synthesized. BACKGROUND: Chromenopyrimidines have attracted significant attention recently because of their activities, such as antiviral and cytotoxic activity. OBJECTIVE: All synthesized compounds were characterized using IR, 1H-NMR, Mass Spectroscopy, and elemental analysis data. METHOD: Molecular docking studies were carried out to determine the inhibitory action of studied ligands against the Main Protease (6LU7, 6m03) of coronavirus (COVID-19). Moreover, the Lipinski Rule parameters were calculated for the synthesized compounds. RESULT: The result of the docking studies showed a significant inhibitory action against the Main protease (Mpro) of SARS-CoV-2, and the binding energy (ΔG) values of the ligands against the protein (6LU7, 6M03) are -7.8 to -9.9 Kcal/mole. CONCLUSION: It may conclude that some ligands were likely to be considered lead-like against the main protease of SARS-CoV-2.

Ferrocenoyl-substituted quinolinone and coumarin as organometallic inhibitors of SARS-CoV-2 3CLpro main protease.

The 3-chymotrypsin-like protease 3CLpro from severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is a potential target for antiviral drug development. In this work, three organometallic ferrocene-modified quinolinones and coumarins were compared to their benzoic acid ester analogues with regard to inhibition of 3CLpro using an HPLC-based assay with a 15mer model peptide as the substrate. In contrast to FRET-based assays, this allows direct identification of interference of buffer constituents with the inhibitors, as demonstrated by the complete abolishment of ebselen inhibitory activity in the presence of dithiothreitol as a redox protectant. The presence of the organometallic ferrocene moiety significantly increased the stability of the title compounds towards hydrolysis. Among the studied compounds, 4-ferrocenyloxy-1-methyl-quinol-2-one was identified as the most stable and potent inhibitor candidate. IC50 values determined for ebselen and this sandwich complex compound are (0.40 ± 0.07) and (2.32 ± 0.21) µM, respectively.

Therapeutic role of columbianadin in human disorders: Medicinal importance, biological properties and analytical aspects

Introduction: Herbal medicines have been used for the treatment of human disorders and associated secondary complications since a very early age. Herbal medicines are composed with a variety of medicinal plants and their derived products. Coumarin class phytochemicals have an important role in medicine due to its anti-coagulant, anti-cancer, anti-HIV and anti-inflammatory activity. Herbal medicines have been gaining popularity in the modern system of medicine mainly due to its safety and efficacy. Columbianadin is an active phytochemical of Angelica pubescens and Heracleum candolleanum. Columbianadin have analgesic, anti-inflammatory, calcium-channel blocking properties and platelet aggregation inhibitory potential. Method(s): Present work described the medicinal importance and pharmacological activities of columbianadin in medicine supported by their traditional medicinal application and pharmacological activities. Scientific data of columbianadin has been collected from PubMed, Google Scholar, Google, Scopus, and Science Direct. However, scientific data of columbianadin published in Journals, books and scientific report have also been collected in the present paper. Analytical data of columbianadin have also been described to know the significance of analytical techniques for the isolation, and identification of columbianadin. Result(s): Scientific data of columbianadin signified the biological importance and therapeutic potential of columbianadin in medicine. Scientific data of columbianadin revealed their biological potential against inflammation, neuropathic pain, cancer, hepatic complications, and immune system disorders. However, biological effectiveness of columbianadin on blood-brain barrier permeability, body tissue, channels and platelet has also been discussed in the present work. Moreover, its therapeutic effectiveness against nematodes has been also summarized in this work. Analytical data for the isolation and identification of columbianadin in different samples has also been presented in this work. Discussion(s): Present work signified the biological importance and therapeutic potential of columbianadin in medicine, which could be used for the treatment of human disorders and associated secondary complications.Copyright © 2022 The Author(s)

Screening of Natural Antivirals Against the COVID-19 Pandemic-A Compilation of Updates

Coronavirus disease 2019 (COVID-19), named by WHO, is a real public health disaster of the third millennium. This highly contagious viral disease has infected the world population and is now a global pandemic. This acute respiratory distress syndrome (ARDS) has severe complica-tions like pneumonitis, respiratory failure, shock, multiorgan failure, and death. Well-defined FDA-approved synthetic is not yet available. Case management strategies like lockdown, use of masks and sanitizers, social distancing, and repurposing of antiviral drugs were initially undertaken to cope with this pandemic. Different broad-spectrum antiviral drugs are being repurposed as one of the treatment modalities. The global vaccination programme with the newly launched COVID-19 vac-cines, Covishield, covaxin, sputnik V, etc., is an ongoing process. Simultaneously, significant research is being carried out in search of natural antivirals and evaluating the potency of food bioac-tives to aid naturistic protection against the coronavirus. This mini-review has compiled the latest updates on the screening and evidence-based mechanistic evaluation of phytochemicals and food bioactives as non-pharmacological adjuvant aid in COVID pandemics.Copyright © 2023 Bentham Science Publishers.

GlPS1 overexpression accumulates coumarin secondary metabolites in transgenic Arabidopsis.

The dried root of Glehnia littoralis is a traditional Chinese herbal medicine mainly used to treat lung diseases and plays an important role in fighting coronavirus disease 2019 pneumonia in China. This study focused on the key enzyme gene GlPS1 for furanocoumarin synthesis in G. littoralis. In the 35S:GlPS1 transgenic Arabidopsis study, the Arabidopsis thaliana-overexpressing GlPS1 gene was more salt-tolerant than Arabidopsis in the blank group. Metabolomics analysis showed 30 differential metabolites in Arabidopsis, which overexpressed the GlPS1 gene. Twelve coumarin compounds were significantly upregulated, and six of these coumarin compounds were not detected in the blank group. Among these differential coumarin metabolites, isopimpinellin and aesculetin have been annotated by the Kyoto Encyclopedia of Genes and Genomes and isopimpinellin was not detected in the blank group. Through structural comparison, imperatorin was formed by dehydration and condensation of zanthotoxol and a molecule of isoprenol, and the difference between them was only one isoprene. Results showed that the GlPS1 gene positively regulated the synthesis of coumarin metabolites in A. thaliana and at the same time improved the salt tolerance of A. thaliana. Supplementary Information: The online version contains supplementary material available at 10.1007/s11240-022-02427-w.

Molecular modeling and simulations of some antiviral drugs, benzylisoquinoline alkaloid, and coumarin molecules to investigate the effects on Mpro main viral protease inhibition.

Background: SARS-CoV-2 is a deadly viral disease and uncounted deaths occurs since its first appearance in the year 2019. The antiviral drugs, benzylisoquinoline alkaloids, and coumarin molecules were searched using different online engines for drug repurposing with SARS-CoV-2 and to investigate the effects on main viral protease (Mpro) upon their bindings. Methods: A database composed of antiviral drugs, benzylisoquinoline alkaloids, and Coumarin molecules was screened through a molecular docking strategy to uncover the interactions of collected molecules with SARS-CoV-2 Mpro. Further, molecular dynamics simulations (MDS) were implemented for 100 ns to calculate the stability of the best complexed molecular scaffold with Mpro. The conformations of the simulated complexes were investigated by using principal component analysis (PCA) and Gibbs energy landscape (FEL) and DSSP together. Next, free binding energy (ΔGbind) was calculated using the mmpbsa method. Results: Molecular docking simulations demonstrate 17 molecules exhibited better binding affinity out of 99 molecules present in the database with the viral protease Mpro, followed ADMET properties and were documented. The Coumarin-EM04 molecular scaffold exhibited interactions with catalytical dyad HIS41, CYS145, and neighboring amino acids SER165 and GLN189 in the catalytical site. The crucial factor RMSD was calculated to determine the orientations of Coumarin-EM04. The Coumarin-EM04 complexed with Mpro was found stable in the binding site during MDS. Furthermore, the free energy binding ΔGbind of Coumarin-EM04 was found to be -187.471 ± 2.230 kJ/mol, and for Remdesivir ΔGbind was -171.926 ± 2.237 kJ/mol with SARS-CoV-2 Mpro. Conclusion: In this study, we identify potent molecules that exhibit interactions with catalytical dyad HIS41 and CYS145 amino acids and unravel Coumarin-EM04 exhibited ΔGbind higher than Remdesivir against Mpro and thus may serve better antiviral agent against SARS-CoV-2.

DFT and In-silico Investigations along with In-vitro Antitumor and Antimicrobial Assessments of Pharmacological Molecules.

BACKGROUND: Molecules, bearing an active methylene bridge, are deemed to be one of the most fruitful and remarkable precursors that have been incorporated in the synthetic strategy of an assortment of bioactive compounds. OBJECTIVE: The reactive methylene derivatives have been endowed with multiple reactions, which target biological and medicinal applications and are resultant from their structural multiplicity and discrete reactivity. METHODS: The present report endeavors to synthesize, characterize, and in-vitro evaluate several novel propanoic acid, coumarin, and pyrazole derivatives as antimicrobial and antiproliferative agents. The in-silico molecular docking, physicochemical, pharmacokinetic/ADMET, bioactivity, and drug likeness predictions were conducted for all the synthesized compounds. RESULTS: The highest docking score is -9.9 and -8.3 kcal/mol respectively for compound 9 (azo-coumarin) and 13 (acrylic acid derivative) with the target proteins E. coli topoisomerase II, DNA gyrase subunit B and PI3K p110α domain, respectively. Moreover, this study predicts the synthesized molecules that may inhibit the novel COVID-19, obtained through virtual screenings only, where compounds 9, 13, 14, 17, and 19 came to the limelight with good docking scores i.e more than 8 Kcal/mol. Safety profiling of the most potent compound 9 was utilized against normal cell line and hemolytic effect on RBCs. CONCLUSION: The in-silico ADMET studies of the synthesized compounds revealed moderate to good drug likeness, high gastro intestinal (GI) absorption, inhibits the Cytochrome CYP2C19 and CYP2C9 and all the derivatives possess non-cancerous nature. The in-vitro screening demonstrated that several of the novel molecules are promising drug candidates. The density function theory (DFT) theoretical calculations were performed to calculate the energy levels of the FMOs and their energy gabs, dipole moment as well as the molecular electrostatic potential. Such parameters along with the physicochemical parameters could be good tool to confirm the biological activity.

A novel coumarin-triazole-thiophene hybrid: synthesis, characterization, ADMET prediction, molecular docking and molecular dynamics studies with a series of SARS-CoV-2 proteins.

Synthesis, characterization and theoretical studies of a novel coumarin-triazole-thiophene hybrid 4-(((4-ethyl-5-(thiophen-2-yl)-4H-1,2,4-triazol-3-yl)thio)methyl)-6,7-dimethyl-2H-chromen-2-one (1), which was fabricated from 4-ethyl-5-(thiophen-2-yl)-4H-1,2,4-triazole-3-thiol and 4-(chloromethyl)-6,7-dimethyl-2H-chromen-2-one, are reported. The resulting compound was characterized by microanalysis, IR, 1H, and 13C APT NMR spectroscopy. The DFT calculations examined the structure and electronic properties of 1 in gas phase. Its reactivity descriptors and molecular electrostatic potential revealed the reactivity and the reactive centers of 1. ADMET properties of 1 were evaluated using the respective online tools. It was established that 1 exhibit positive gastrointestinal absorption properties and negative human blood-brain barrier penetration. The Toxicity Model Report revealed that 1 belongs to toxicity class 4. Molecular docking was additionally applied to study the interaction of 1 with some SARS-CoV-2 proteins. It was established that the title compound is active against all the applied proteins with the most efficient interaction with Papain-like protease (PLpro). The interaction of 1 with the applied proteins was also studied using molecular dynamics simulations. Graphical abstract: A novel coumarin-triazole-thiophene hybrid 4-(((4-ethyl-5-(thiophen-2-yl)-4H-1,2,4-triazol-3-yl)thio)methyl)-6,7-dimethyl-2H-chromen-2-one (1) is reported. The structure and electronic properties of 1 were examined by the DFT calculations. ADMET properties of 1 were also evaluated. Molecular docking and molecular dynamics simulations were applied to study interactions of 1 with a series of the SARS-CoV-2 proteins. Supplementary Information: The online version contains supplementary material available at 10.1007/s12039-022-02127-0.

Coumarin-based combined computational study to design novel drugs against Candida albicans.

Candida species cause the most prevalent fungal illness, candidiasis. Candida albicans is known to cause bloodstream infections. This species is a commensal bacterium, but it can cause hospital-acquired diseases, particularly in COVID-19 patients with impaired immune systems. Candida infections have increased in patients with acute respiratory distress syndrome. Coumarins are both naturally occurring and synthetically produced. In this study, the biological activity of 40 coumarin derivatives was used to create a three-dimensional quantitative structure activity relationship (3D-QSAR) model. The training and test minimum inhibitory concentration values of C. albicans active compounds were split, and a regression model based on statistical data was established. This model served as a foundation for the creation of coumarin derivative QSARs. This is a unique way to create new therapeutic compounds for various ailments. We constructed novel structural coumarin derivatives using the derived QSAR model, and the models were confirmed using molecular docking and molecular dynamics simulation.

Composition decipherment of Ficus pumila var. awkeotsang and its potential on COVID-19 symptom amelioration and in silico prediction of SARS-CoV-2 interference

The jelly from achenes of Ficus pumila var. awkeotsang (FPAA) is a famous beverage ingredient in Taiwan. In this work, ficumarin (1), a new compound was obtained from its twigs (FPAT) and elucidated with comprehensive spectroscopic data. The biosynthetic origin was proposed from the p-coumaroyl-CoA pathway. Alloxanthoxyletin, betulinic acid, and catechin were identified as the major and active constituents responsible for relieving neutrophilic inflammation by FPAT. Among them, the most potent alloxanthoxyletin was found to interact with PRO350 and GLU377 of human INOSOX. Further, Nrf2 activating capacity of the FPAT fraction and its coumarins was confirmed. With the analysis of LC-MS/MS data and feature-based molecular networking, coumarins were found as the dominant and responsible components. Notably, alloxanthoxyletin increased Nrf2 expression by up to 816.8 +/- 58% due to the interacting with the VAL561, THR560 and VAL420 residues of 5FNQ protein. COVID-19 Docking Server simulation indicated that pyranocoumarins would promisingly interfere with the life cycle of SARS-CoV-2. FPAT was proven to exert. Copyright © 2022 Taiwan Food and Drug Administration.

IDENTIFICATION OF NOVEL COUMARIN BASED COMPOUNDS AS POTENTIAL INHIBITORS OF THE 3-CHYMOTRYPSIN-LIKE MAIN PROTEASE OF SARS-COV-2 USING DFT, MOLECULAR DOCKING AND MOLECULAR DYNAMICS SIMULATION STUDIES

SARS-CoV-2 is the pandemic disease-causing agent COVID-19 with high infection rates. Despite the progress made in vaccine development, there is an urgent need for the identification of antiviral compounds that can tackle better the different phases of SARS-CoV-2. The main protease (Mpro or 3CLpro) of SARS-CoV-2 has a crucial role in viral replication and transcription. In this study, an in silico method was executed to elucidate the inhibitory potential of the synthesized 6-tert-octyl and 6-8-ditert-butyl coumarin compounds against the major protease of SARS-CoV-2 by comprehensive molecular docking and density functional theory (DFT), ADMET properties and molecular dynamics simulation approaches. Both compounds shown favorable interactions with the 3CLpro of the virus. From DFT calculations, HOMO-LUMO values and global descriptors indicated promising results for these compounds. Furthermore, molecular dynamics studies revealed that these ligand-receptor complexes remain stable during simulations and both compounds showed considerably high binding affinity to the main SARS-CoV-2 protease. The results of the study suggest that the coumarin compounds 6-tert-octyl and 6-8-ditert-butyl could be considered as promising scaffolds for the development of potential COVID-19 inhibitors after further studies.

The role of DOACs in anticoagulant treatment in a tertiary Hospital of Thessaloniki, Greece

Introduction: Low molecular weight heparins are used extensively in anticoagulant therapy, due to their safer profile, in comparison to other anticoagulants. Direct Oral AntiCogulants (DOACs) have been initiated in anticoagulant therapy as a safer treatment choice than coumarin derivatives. Objectives: The aim of this study was to investigate the use of oral and injectable anticoagulants, and especially the place of DOACs in anticoagulant treatment, in a tertiary Hospital of Thessaloniki, Greece. Methods: The data were collected by investigating prescriptions from the Hospital Pharmacy of a tertiary Hospital in Thessaloniki, Greece. Prescriptions of oral and injectable anticoagulants for hospitalized patients were collected during the period from June to September 2021. The consumption of the following oral and injectable anticoagulants was recorded in DDDs: acenocumarol, rivaroxaban, apixaban, dabigatran, heparin, enoxaparin, tinzaparin, bemiparin and fondaparinux. Results: The total amount of anticoagulants used was 53,041 DDDs, of which 97,9% were injectable anticoagulants whereas 2,1% were oral anticoagulants. DOACs represented the 1,8% of the anticoagulants used. The consumption of injectable anticoagulants for the hospitalized patients was 51,936 DDDs, of which 63.5% was enoxaparin, 18.5% was tinzaparin, 6.3% was heparin, 6.1% was bemiparin, and 5.6% was fondaparinux. The consumption of acenocumarol was 176 DDDs and the consumption of DOACs was 929 DDDs, with the percentage of rivaroxaban, apixaban, and dabigatran being 46%, 45% and 9% respectively. Indications with the highest prevalence for patients on enoxaparin was COVID 19, heart failure, stroke, angina pectoris, malignancy. Indications with the highest prevalence for patients on tinzaparin was COVID 19, malignancy, stroke. Indications with the highest prevalence for patients on bemiparin was malignancy, COVID 19, aortic valve disease, stroke. Heart failure, stroke and atrial fibrillation were the indications with highest prevalence in patients on DOACs. Acenocumarol was used mainly for heart failure, stroke and aortic valve stenosis. Conclusion: Injectable anticoagulants, and mainly low molecular weight heparins were the treatment of choice in hospitalized patients. Oral anticoagulants represented only a very small proportion (2,1%) of the anticoagulants used. DOACs have replaced coumarin derivatives, representing the 86% of oral anticoagulants in clinical use. Nevertheless, the percentage of DOACs was very low (1.8%) in the total consumption of anticoagulants, with rivaroxaban and apixaban being the most commonly used DOACs. Injectable anticoagulants, especially enoxaparin, are preferred by the clinicians as a safer choice for managing high risk thrombosis in hospitalized patients. DOACs, Direct Oral AntiCogulants, anticoagulants, NOACs.

Ayurveda and Siddha systems polyherbal formulations to treat COVID-19 caused by SARS-CoV-2 and brief insight on application of Molecular Docking and SWISS Target prediction tools to study efficacy of active molecules

Ayurveda and Siddha systems are the two ancient medical systems originated in India more than 4000 years ago had given many formulary and treatment methods against influenza like infections. Kabasura churan from Siddha system and Maha sudharshan churan from the Ayurvedic system are the two major formulations along with many other individual herbs mentioned in the texts to treat Influenza like infections. Kabasura churan and Maha Sudarshan churan both have antipyretic, analgesic and anti-inflammatory effects. Both formulations were prepared according to Siddha and Ayurvedic texts. Herbs mentioned in both formulations like Turmeric, Tulsi (Basil), Kalmegh (Andrographis), Black Pepper, Liquorice (Mulethi), and Dronapushpi (Leucas) etc., had direct antiviral effect. Herbs like Aswagandha, Ginger, Guduchi (Tinospora), Kulanjan (Galangal) etc., had immunomodulatory and anti-inflammatory effect. Active compounds from different herbs were selected to study their antiviral activity through molecular docking algorithm. Application of modern of tools like Bioinformatics and Highthroughput screening methods can predict the efficacy of the ancient documented formulations and can be compared as per their literature. Compounds like curcumin, Glycyrrhizin, Ursolic acid, Quercetin, Andrographolide, Coumarins etc. were showed polyspecific activity like inhibition of Spike protein, Furin, Main Protease (Mpro) and Papain like Proteases (PLpro). Thus we propose use of Kabasura churan and Maha Sudharshan churan as alternative complementary medicine as a palliative treatment against COVID-19 caused by SARS-CoV-2 by conducting proper Randomized Clinical Trials.

Ayurvedic antiviral agents: Overview of medicinal plants perspective

In recent years, it has been reported that many herbal plants contain antiviral agents which combat a human disease that is caused by pathogenic viruses. The natural products which are obtained from plants as antiviral agents against viruses have gone through researches to check the efficacy and potentials of the herbal products in the prevention of viral disorders. On the basis of randomized controlled studies and in-vivo studies, and in-vitro studies, some agents are utilized all across the globe. Progressively numerous studies on therapy of antivirals have been increased. Though, efficacy remains disputable for antiviral drugs that are employed for viral disorders. The viral diseases are challenging for the health of people around the world cause significant increase in mortality and enhance crises. There are many synthetic antiviral drugs that have a large number of side effects and have narrow therapeutic window range, while in the other hand herbal formulations have minimized side effects. The advantages of herbal formulation over synthetic drugs encourage us to devise and expand new herbal moieties against the emerging viral infections. The medicinal plants contain phytochemicals that have antiviral properties. In this paper, the activity of antiviral agents from medicinal plants which have importance in Ayurveda, are discussed along with their source.

Therapeutic potential of plant secondary metabolites in treatment of respiratory viral diseases: A review

Respiratory viral infections are a major public health concern because of their global occurrence, ease of spread and considerable morbidity and mortality. Medical treatments for viral respiratory diseases primarily involve providing relief from symptoms like pain and discomfort rather than treating the infection. Very few antiviral medications have been approved with restrictive usage, high cost, unwanted side effects and limited availability. Plants with their unique metabolite composition and high remedial values offer unique preventive and therapeutic efficacy in treatment of viral infections. The present review is focused on the types and mode of action of plant secondary metabolites that have been used successfully ί in the treatment of infections caused by respiratory viruses like Influenza, SARS, MERS, RSV etc. Plant metabolites such as phenolics, alkaloids, terpenoids and oligosaccharides inhibit attachment and entry of the virus. Others such as flavonoids, viz quercetin and baicalein, alkaloids viz sanguinarine, berberine and emetine, specific lipids and fatty acids prevent viral replication and protein synthesis. These metabolites have the potential to be used as lead molecules that can be optimized to develop potent drugs for effectively combating pandemics caused by respiratory viruses.

Isolation and In Silico SARS-CoV-2 Main Protease Inhibition Potential of Jusan Coumarin, a New Dicoumarin from Artemisia glauca.

A new dicoumarin, jusan coumarin, (1), has been isolated from Artemisia glauca aerial parts. The chemical structure of jusan coumarin was estimated, by 1D, 2D NMR as well as HR-Ms spectroscopic methods, to be 7-hydroxy-6-methoxy-3-[(2-oxo-2H-chromen-6-yl)oxy]-2H-chromen-2-one. As the first time to be introduced in nature, its potential against SARS-CoV-2 has been estimated using various in silico methods. Molecular similarity and fingerprints experiments have been utilized for 1 against nine co-crystallized ligands of COVID-19 vital proteins. The results declared a great similarity between Jusan Coumarin and X77, the ligand of COVID-19 main protease (PDB ID: 6W63), Mpro. To authenticate the obtained outputs, a DFT experiment was achieved to confirm the similarity of X77 and 1. Consequently, 1 was docked against Mpro. The results clarified that 1 bonded in a correct way inside Mpro active site, with a binding energy of -18.45 kcal/mol. Furthermore, the ADMET and toxicity profiles of 1 were evaluated and showed the safety of 1 and its likeness to be a drug. Finally, to confirm the binding and understand the thermodynamic characters between 1 and Mpro, several molecular dynamics (MD) simulations studies have been administered. Additionally, the known coumarin derivative, 7-isopentenyloxycoumarin (2), has been isolated as well as ß-sitosterol (3).

Molecular docking and dynamic simulations study for repurposing of multitarget coumarins against SARS-CoV-2 main protease, papain-like protease and RNA-dependent RNA polymerase

Proteases and RNA-Dependent RNA polymerase, major enzymes which are essential targets involved in the life and replication of SARS-CoV-2. This study aims at in silico examination of the potential ability of coumarins and their derivatives to inhibit the replication of SARS-Cov-2 through multiple targets, including the main protease, papain-like protease and RNA-Dependent RNA polymerase. Several coumarins as biologically active compounds were studied, including coumarin antibiotics and some naturally reported antiviral coumarins. Aminocoumarin antibiotics, especially coumermycin, showed a high potential to bind to the enzymes' active site, causing possible inhibition and termination of viral life. They demonstrate the ability to bind to residues essential for triggering the crucial cascades within the viral cell. Molecular dynamics simulations for 50 ns supported these data pointing out the formation of rigid, stable Coumermycin/enzyme complexes. These findings strongly suggest the possible use of Coumermycin, Clorobiocin or Novobiocin in the fight against COVID-19, but biological evidence is still required to support such suggestions.

Synthetic Coumarin Derivatives as SARS-CoV-2 Major Protease Inhibitors: Design, Synthesis, Bioevaluation and Molecular Docking

Major protease enzyme of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2 M-pro) is one of the key enzymes of viral replication which amuses many scientists as a promising drug target. Nonetheless, few studies reported new synthetic small molecule inhibitors of the M-pro but many were repurposing drugs such as chloroquine or predicting the activity based on in silico results. This study had the privilege of synthesizing new coumarin-based derivatives with possible M-pro inhibition based on the previously reported ligand-based pharmacophore model. Compound 3 showed comparable M-pro inhibitory activity to chloroquine with IC50 15.0 and 13.1 mu g/mL, respectively. Moreover, compounds 4 b, 4 d, 5 b, 5 c, 5 e and 5 g managed to inhibit the M-pro enzymatic activity by more than 50.0 % at 100 mu M among which 5 g showed 63.9 % inhibition and IC50 25.8 mu g/mL. The binding conformations of the promising compounds were illustrated using molecular docking as well as their drug-likeness and ADMET properties. A pharmacophore model was generated using the compounds with more than 50.0 % M-pro inhibition to annotate the essential moieties for enzyme binding. All compounds were fully characterized using the conventional spectroscopic and microanalyses methods.

Therapeutic Journey and Recent Advances in the Synthesis of Coumarin Derivatives.

BACKGROUND: Coumarin is an oxygen-containing compound in medicinal chemistry. Coumarin plays an important role in both natural systems like plants and synthetic medicinal applications as drug molecules. Many structurally different coumarin compounds have been found to possess a wide range of similarities with the vital molecular targets in terms of their pharmacological action and small modifications in their structures, resulting in significant changes in their biological activities. OBJECTIVE: This review provides detailed information regarding the studies focused on the recent advances in various pharmacological aspects of coumarins. METHODS: Various oxygen-containing heterocyclic compounds represent remarkable biological significance. The fused aromatic oxygen-heterocyclic nucleus can change its electron density, thus altering the chemical, physical and biological properties, respectively, due to its multiple binding modes with the receptors, which play a crucial role in the pharmacological screening of drugs. Several heterocyclic compounds have been synthesized which have their nuclei derived from various plants and animals. In coumarins, the benzene ring is fused with a pyrone nucleus which provides stability to the nucleus. Coumarins have shown a wide range of pharmacological activities, such as anti-tumor, anticoagulant, anti-inflammatory, anti-oxidant, antiviral, antimalarial, anti-HIV, antimicrobial, etc. Results: Reactive oxygen species, like superoxide anion, hydroxyl radical, and hydrogen peroxide, are a type of unstable molecule containing oxygen, which reacts with other molecules in the cell during metabolism; however, when the number of reactive oxygen species increases, it may lead to cytotoxicity, thereby damaging the biological macromolecules. Hydroxyl Radical (OH) is a strong oxidizing agent and it is responsible for the cytotoxicity caused by oxygen in different plants, animals, and other microbes. Coumarin is the oldest and effective compound having antimicrobial, anti-inflammatory, antioxidant, antidepressant, analgesic, anticonvulsant activities, etc. Naturally existing coumarin compounds act against SARS-CoV-2 by preventing viral replication and targeting the active site against the Mpro target protein. CONCLUSION: This review highlights the different biological activities of coumarin derivatives. In this review, we provide an updated summary of the researches which are related to recent advances in biological activities of coumarins analogs and their most recent activities against COVID -19. Natural compounds act as a rich resource for novel drug development against various SARS-CoV-2 viral strains and viruses, like herpes simplex virus, influenza virus, human immunodeficiency virus, hepatitis B and C viruses, middle east respiratory syndrome, and severe acute respiratory syndrome.

Synthesis and Biological Evaluation of Harmirins, Novel Harmine-Coumarin Hybrids as Potential Anticancer Agents.

As cancer remains one of the major health burdens worldwide, novel agents, due to the development of resistance, are needed. In this work, we designed and synthesized harmirins, which are hybrid compounds comprising harmine and coumarin scaffolds, evaluated their antiproliferative activity, and conducted cell localization and cell cycle analysis experiments. Harmirins were prepared from the corresponding alkynes and azides under mild reaction conditions using Cu(I) catalyzed azide-alkyne cycloaddition, leading to the formation of the 1H-1,2,3-triazole ring. Antiproliferative activity of harmirins was evaluated in vitro against four human cancer cell lines (MCF-7, HCT116, SW620, and HepG2) and one human non-cancer cell line (HEK293T). The most pronounced activities were exerted against MCF-7 and HCT116 cell lines (IC50 in the single-digit micromolar range), while the most selective harmirins were 5b and 12b, substituted at C-3 and O-7 of the ß-carboline core and bearing methyl substituent at position 6 of the coumarin ring (SIs > 7.2). Further experiments demonstrated that harmirin 12b is localized exclusively in the cytoplasm. In addition, it induced a strong G1 arrest and reduced the percentage of cells in the S phase, suggesting that it might exert its antiproliferative activity through inhibition of DNA synthesis, rather than DNA damage. In conclusion, harmirin 12b is a novel harmine and coumarin hybrid with significant antiproliferative activity and warrants further evaluation as a potential anticancer agent.