Green and rapid and instrumental one-pot method for the synthesis of imidazolines having potential anti-SARS-CoV-2 main protease activity.

The Severe Acute Respiratory Syndrome CoronaVirus 2 (SARS-CoV-2) is responsible for ongoing epidemics in humans and some other mammals and has been declared a public health emergency of international concern. In this project, several small non-peptide molecules were synthesized to inhibit the major proteinase (Mpro) of SARS-CoV-2 using rational strategies of drug design and medicinal chemistry. Mpro is a key enzyme of coronaviruses and plays an essential role in mediating viral replication and transcription in human lung epithelial and stem cells, making it an attractive drug target for SARS-CoV. The antiviral potential of imidazoline derivatives as inhibitors of (SARS-CoV-2) Mpro was evaluated using in-silico techniques such as molecular docking simulation, molecular dynamics (MD), and ADMET prediction. The docking scores of these imidazoline derivatives were compared to that of the N3 crystal inhibitor and showed that most of these compounds, particularly compound E07, interacted satisfactorily in the active site of the coronavirus and strongly interacted with the residues (Met 165, Gln 166, Met 165, His 41, and Gln 189). Furthermore, the results were confirmed by MD simulations after exposure to long-term MD simulations and ADMET predictions.

Antiviral Effects of Asian Natural Products Targeting SARS, MERS, and COVID-19

Viral diseases initiated by Coronavirus (CoV) have become the major public health problems worldwide in the last two decades. The recent emergence of the deadly COVID-19 due to SARS-CoV-2 has created unprecedented pandemic situations around the globe making the need for antiviral molecules to treat it. Encountering the health conditions of the patients with synthetic molecules has shown some unpredictable results, including side effects. To face this complex situa-tion, natural products can be good sources of enormous treatment options with fewer side effects. Wide diversity, easy availability, and a good number of scientific researches on Asian origin natural products can be a great tool to meet this critical situation. This paper reviews the currently available Asian natural products with potential antiviral effects on CoV. It includes the potential natural products of whole plant extract, partial plant extract, isolated pure compounds, and isolated pure set of compounds. Besides, the available information of in vitro and in silico from very recent pa-pers are also summarized for the ease of future research. As a rapid search for a potential anti-CoV therapy is undergoing, Asian natural products will provide promising results but still, there are many challenges in front of us, including the robust in vitro assay to confirm the antiviral property, toxicity analysis, and fulfillment of regulatory needs. The use of appropriate natural products with the potential for a safe and more effective anti-CoV property requires multidisciplinary research with preclinical and clinical researchers, which will improve their clinical applications.Copyright © 2021 Bentham Science Publishers.

Screening of honey bee pollen constituents against COVID-19: an emerging hot spot in targeting SARS-CoV-2-ACE-2 interaction.

The attachment of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike to angiotensin-converting enzyme 2 (ACE-2) leads the cell fusion process, so spike blockade may be a promising therapy combating COVID-19. Bee pollen bioflavonoids with intrinsic bioactivities are of outmost importance to block SARS-CoV-2-ACE-2 interaction. Herein, we conducted a molecular docking assessment through natural phenolics/non-phenolics of pollen to investigate their affinity against SARS-CoV-2 spike. Finally, kaempferol 3-neohesperidoside 7-O-rhamnoside (compound a), quercetin 7-rhamnoside (compound b), delphinidin-3-O-(6-p-coumaroyl) glucoside (compound c), and luteolin-7-O-6″-malonylglucoside (compound d) showed the lowest binding affinity of -8.1, -7.7, -7.3 and -6.7 kcal/mol. The docking procedure was validated using protein-protein interactions between ACE-2 and SARS-CoV-2 RBD via HADDOCK webserver. MD simulations were fulfilled to investigate different ligands' effects on protein movements. Collectively, compound a may possess the potency to disturb the binding of SARS-CoV-2 spike-ACE-2, which can be on the call for further in vitro and in vivo study to investigate its antiviral potential against SARS-CoV-2.

In Silico Screening of Drugs That Target Different Forms of E Protein for Potential Treatment of COVID-19.

Recently the E protein of SARS-CoV-2 has become a very important target in the potential treatment of COVID-19 since it is known to regulate different stages of the viral cycle. There is biochemical evidence that E protein exists in two forms, as monomer and homopentamer. An in silico screening analysis was carried out employing 5852 ligands (from Zinc databases), and performing an ADMET analysis, remaining a set of 2155 compounds. Furthermore, docking analysis was performed on specific sites and different forms of the E protein. From this study we could identify that the following ligands showed the highest binding affinity: nilotinib, dutasteride, irinotecan, saquinavir and alectinib. We carried out some molecular dynamics simulations and free energy MM-PBSA calculations of the protein-ligand complexes (with the mentioned ligands). Of worthy interest is that saquinavir, nilotinib and alectinib are also considered as a promising multitarget ligand because it seems to inhibit three targets, which play an important role in the viral cycle. On the other side, saquinavir was shown to be able to bind to E protein both in its monomeric as well as pentameric forms. Finally, further experimental assays are needed to probe our hypothesis derived from in silico studies.

In Silico Evaluation of Natural Flavonoids as a Potential Inhibitor of Coronavirus Disease.

The recent coronavirus disease (COVID-19) outbreak in Wuhan, China, has led to millions of infections and the death of approximately one million people. No targeted therapeutics are currently available, and only a few efficient treatment options are accessible. Many researchers are investigating active compounds from natural plant sources that may inhibit COVID-19 proliferation. Flavonoids are generally present in our diet, as well as traditional medicines and are effective against various diseases. Thus, here, we reviewed the potential of flavonoids against crucial proteins involved in the coronavirus infectious cycle. The fundamentals of coronaviruses, the structures of SARS-CoV-2, and the mechanism of its entry into the host's body have also been discussed. In silico studies have been successfully employed to study the interaction of flavonoids against COVID-19 Mpro, spike protein PLpro, and other interactive sites for its possible inhibition. Recent studies showed that many flavonoids such as hesperidin, amentoflavone, rutin, diosmin, apiin, and many other flavonoids have a higher affinity with Mpro and lower binding energy than currently used drugs such as hydroxylchloroquine, nelfinavir, ritonavir, and lopinavir. Thus, these compounds can be developed as specific therapeutic agents against COVID-19, but need further in vitro and in vivo studies to validate these compounds and pave the way for drug discovery.

Designing of Thiazolidinones for COVID-19 and its Allied Diseases: An In silico Evaluation.

In silico studies in terms of density functional theory (DFT), molecular docking, and ADMET (absorption, distribution, metabolism, excretion and toxicity) were performed for 55 thiazolidinones compounds derived from different amines and aldehydes. DFT is a computational quantum mechanical modeling method used to predict the various properties of the compounds. Different parameters such as Electronegativity (x), Chemical Hardness (ŋ), Chemical Potential (µ), Ionization potential (IP), and Electron Affinity (EA), etc. were calculated by Koopmans theorem. The compounds were docked with Molecular Operating Environment (MOE) software using already reported PDB files of BChE, AChE, and α-glucosidase. To analyze the Spike Glycoprotein of SARS-Cov-2 and heterocyclic compounds, molecular interactions study was carried out between Spike Glycoprotein of SARS-Cov-2 (6VXX) and 55 synthetic heterocyclic compounds. It was performed by the utilization of PyRx Virtual Screening Tool and AutoDock Vina based virtual environment was used in PyRx. Maximum binding affinity was observed with compound A7 which was -8.7 kcal/mol and then with A5 which was -8.5 respectively. In the case of the AChE enzyme, B5 has a maximum docking score of -12.9027 kcal/mol while C7 depicted the maximum score for the BChE enzyme with a value of -8.6971 kcal/mol. The docking studies revealed that C6 compound has maximum binding capacity toward glucosidase (-14.8735 kcal/mol). ADMET properties of under consideration compounds were determined by Swiss online-based software which concluded that these molecules have a drug-like properties and having no violation.

Deciphering the Potential of Pre and Pro-Vitamin D of Mushrooms against Mpro and PLpro Proteases of COVID-19: An In Silico Approach.

Vitamin D's role in combating the SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2), the virus causing COVID-19, has been established in unveiling viable inhibitors of COVID-19. The current study investigated the role of pre and pro-vitamin D bioactives from edible mushrooms against Mpro and PLpro proteases of SARS-CoV-2 by computational experiments. The bioactives of mushrooms, specifically ergosterol (provitamin D2), 7-dehydrocholesterol (provitamin-D3), 22,23-dihydroergocalciferol (provitamin-D4), cholecalciferol (vitamin-D3), and ergocalciferol (vitamin D2) were screened against Mpro and PLpro. Molecular docking analyses of the generated bioactive protease complexes unravelled the differential docking energies, which ranged from -7.5 kcal/mol to -4.5 kcal/mol. Ergosterol exhibited the lowest binding energy (-7.5 kcal/mol) against Mpro and PLpro (-5.9 kcal/mol). The Molecular Mechanics Poisson-Boltzmann Surface Area (MMPBSA) and MD simulation analyses indicated that the generated complexes were stable, thus affirming the putative binding of the bioactives to viral proteases. Considering the pivotal role of vitamin D bioactives, their direct interactions against SARS-CoV-2 proteases highlight the promising role of bioactives present in mushrooms as potent nutraceuticals against COVID-19.

Molecular Docking and Computational Exploration of Isolated Drugs from Daphne Species Against COVID-19

The SARS-CoV-2 has initiated in Wuhan city of China and then extend all around the world as a health emergency. It begins a new research area to produce potential drugs using data-driven approaches to identify potential therapies for the treatment of the virus. This is the time to develop specific antiviral drugs using molecular docking, quantum chemical approaches, and natural products. The protease inhibitors that constitute plant derivatives may become highly efficient to cure virus-prompted illnesses. A systematic study of isolated phytochemicals was executed then frontier molecular orbitals, docking score, molecular descriptors, and active sites were compared with favipiravir, dexamethasone, redeliver, and hydroxychloroquine which are being used against COVID19 nowadays. This is the first study on the phytochemicals of Daphne species to explore their anti-SARS-CoV-2 behavior by molecular docking and quantum chemical methods.

Phytochemicals present in Indian ginseng possess potential to inhibit SARS-CoV-2 virulence: A molecular docking and MD simulation study.

Coronaviruses are deadly and contagious pathogens that affects people in different ways. Researchers have increased their efforts in the development of antiviral agents against coronavirus targeting Mpro protein (main protease) as an effective drug target. The present study explores the inhibitory potential of characteristic and non-characteristic Withania somnifera (Indian ginseng) phytochemicals (n ≈ 100) against SARS-Cov-2 Mpro protein. Molecular docking studies revealed that certain W. somnifera compounds exhibit superior binding potential (-6.16 to -12.27 kcal/mol) compared to the standard inhibitors (-2.55 to -6.16 kcal/mol) including nelfinavir and lopinavir. The non-characteristic compounds (quercetin-3-rutinoside-7-glucoside, rutin and isochlorogenic acid B) exhibited higher inhibitory potential in comparison to characteristic W. somnifera compounds withanolide and withanone. Molecular dynamics (MD) simulation studies of the complex for 100 ns confirm favorable and stable binding of the lead molecule. The MMPBSA calculation of the last 10 ns of the protein-ligand complex trajectory exhibited stable binding of quercetin-3-rutinoside-7-glucoside at the active site of SARS-Cov-2 Mpro. Taken together, the study demonstrates that the non-characteristic compounds present in W. somnifera possess enhanced potential to bind SARS-Cov-2 Mpro active site. We further recommend in vitro and in vivo experimentation to validate the anti-SARS-CoV-2 potential of these lead molecules.

Recent efforts for drug identification from phytochemicals against SARS-CoV-2: Exploration of the chemical space to identify druggable leads.

Nature, which remains a central drug discovery pool, is always looked upon to find a putative druggable lead. The natural products and phytochemical derived from plants are essential during a global health crisis. This class represents one of the most practical and promising approaches to decrease pandemic's intensity owing to their therapeutic potential. The present manuscript is therefore kept forth to give the researchers updated information on undergoing research in allied areas of natural product-based drug discovery, particularly for Covid-19 disease. The study briefly shreds evidence from in vitro and in silico researches done so far to find a lead molecule against Covid-19. Following this, we exhaustively explored the concept of chemical space and molecular similarity parameters for the drug discovery about the lead(s) generated from in silico-based studies. The comparison was drawn using FDA-approved anti-infective agents during 2015-2020 using key descriptors to evaluate druglike properties. The outcomes of results were further corroborated using Molecular Dynamics studies which suggested the outcomes in alignment with chemical space ranking. In a nutshell, current research work aims to provide a holistic strategic approach to drug design, keeping in view the identified phytochemicals against Covid-19.

Andrographolide as a potential inhibitor of SARS-CoV-2 main protease: an in silico approach.

SARS-CoV-2 virus which caused the global pandemic the Coronavirus Disease- 2019 (COVID-2019) has infected about 1,203,959 patients and brought forth death rate about 64,788 among 206 countries as mentioned by WHO in the month of April 2020. The clinical trials are underway for Remdesivir, an investigational anti-viral drug from Gilead Sciences. Antimalarial drugs such as Chloroquine and Hydroxychloroquine derivatives are being used in emergency cases; however, they are not suitable for patients with conditions like diabetes, hypertension and cardiac issues. The lack of availability of approved treatment for this disease calls forth the scientific community to find novel compounds with the ability to treat it. This paper evaluates the compound Andrographolide from Andrographis paniculata as a potential inhibitor of the main protease of SARS-COV-2 (Mpro) through in silico studies such as molecular docking, target analysis, toxicity prediction and ADME prediction. Andrographolide was docked successfully in the binding site of SARS-CoV-2 Mpro. Computational approaches also predicts this molecule to have good solubility, pharmacodynamics property and target accuracy. This molecule also obeys Lipinski's rule, which makes it a promising compound to pursue further biochemical and cell based assays to explore its potential for use against COVID-19.Communicated by Ramaswamy H. Sarma.