Korupensamine A, but not its atropisomer, korupensamine B, inhibits SARS-CoV-2 in vitro by targeting its main protease (Mpro)

By combining docking and molecular dynamics simulations, we explored a library of 65 mostly axially chiral naphthylisoquinoline alkaloids and their analogues, with most different molecular architectures and structural analogues, for their activity against SARS-CoV-2. Although natural biaryls are often regarded without consideration of their axial chirality, they can bind to protein targets in an atroposelective manner. By combining docking results with steered molecular dynamics simulations, we identified one alkaloid, korupensamine A, that atropisomer-specifically inhibited the main protease (Mpro) activity of SARS-CoV-2 significantly in comparison to the reference covalent inhibitor GC376 (IC50 = 2.52 ± 0.14 and 0.88 ± 0.15 μM, respectively) and reduced viral growth by five orders of magnitude in vitro (EC50 = 4.23 ± 1.31 μM). To investigate the binding pathway and mode of interaction of korupensamine A within the active site of the protease, we utilized Gaussian accelerated molecular dynamics simulations, which reproduced the docking pose of korupensamine A inside the active site of the enzyme. The study presents naphthylisoquinoline alkaloids as a new class of potential anti-COVID-19 agents. Graphical abstract Image 1

Korupensamine A, but not its atropisomer, korupensamine B, inhibits SARS-CoV-2 in vitro by targeting its main protease (Mpro).

By combining docking and molecular dynamics simulations, we explored a library of 65 mostly axially chiral naphthylisoquinoline alkaloids and their analogues, with most different molecular architectures and structural analogues, for their activity against SARS-CoV-2. Although natural biaryls are often regarded without consideration of their axial chirality, they can bind to protein targets in an atroposelective manner. By combining docking results with steered molecular dynamics simulations, we identified one alkaloid, korupensamine A, that atropisomer-specifically inhibited the main protease (Mpro) activity of SARS-CoV-2 significantly in comparison to the reference covalent inhibitor GC376 (IC50 = 2.52 ± 0.14 and 0.88 ± 0.15 µM, respectively) and reduced viral growth by five orders of magnitude in vitro (EC50 = 4.23 ± 1.31 µM). To investigate the binding pathway and mode of interaction of korupensamine A within the active site of the protease, we utilized Gaussian accelerated molecular dynamics simulations, which reproduced the docking pose of korupensamine A inside the active site of the enzyme. The study presents naphthylisoquinoline alkaloids as a new class of potential anti-COVID-19 agents.

Evaluation of antiviral activity of Carica papaya leaves against SARS-CoV-2 assisted by metabolomic profiling.

The COVID-19 pandemic caused a huge health crisis all over the globe. SARS-CoV-2 is the virus responsible for the disease and it is highly contagious leaving millions of confirmed infected cases and a dangerous death toll. Carica papaya is a tropical plant known for its antiviral activity since it possesses different classes of compounds that are believed to combat various viral classes. In this study, the extracts prepared from C. papaya leaves cultivated in Egypt were evaluated for their anti-SARS-CoV-2 activity using crystal violet assay and for their cytotoxicity through MTT assay. The total methanolic extract, n-hexane, ethyl acetate, and n-butanol fractions of papaya leaves were used in the study and the results revealed that the n-hexane fraction has a high anti-SARS-CoV-2 activity with an IC50 value = 1.98 µg mL-1. Moreover, it also showed a high selectivity index value = 104.7. Dereplication of the secondary metabolites in the crude methanolic extract of C. papaya leaves revealed the presence of different classes of compounds including sterols, terpenes, fatty acid, alkaloids and flavonoids that are known to possess antiviral activities against various classes of viruses. The current study was assisted by molecular docking, molecular dynamics simulation and MM-PBSA calculations for the annotated compounds against 6 SARS-CoV-2 target proteins. The results of these in silico-based investigations showed high to moderate binding on the targeted proteins. This postulation may instigate further research studies concerning the compounds responsible for this high anti-SARS-CoV-2 activity of the n-hexane fraction of C. papaya leaves.

New Halogenated Compounds from Halimeda macroloba Seaweed with Potential Inhibitory Activity against Malaria.

Malaria is one of the most important infectious diseases worldwide. The causative of the most severe forms of malaria, Plasmodium falciparum, has developed resistances against all the available antimalarial drugs. In the present study, the phytochemical investigation of the green seaweed Halimeda macroloba has afforded two new compounds 1-2, along with 4 known ones 3-6. The structures of the compounds had been confirmed using 1& 2D-NMR and HRESIMS analyses. Extensive machine-learning-supported virtual-screening suggested cytochrome-C enzyme as a potential target for compound 2. Docking, absolute-binding-free-energy (ΔGbinding) and molecular-dynamics-simulation (MDS) of compound 2 revealed the strong binding interaction of this compound with cytochrome-C. In vitro testing for crude extract and isolated compounds revealed the potential in vitro inhibitory activity of both extract and compound 2 against P. falciparum. The crude extract was able to inhibit the parasite growth with an IC50 value of 1.8 ± 0.35 µg/mL. Compound 2 also showed good inhibitory activity with an IC50 value of 3.2 ± 0.23 µg/mL. Meanwhile, compound 6 showed moderate inhibitory activity with an IC50 value of 19.3 ± 0.51 µg/mL. Accordingly, the scaffold of compound 2 can be considered as a good lead compound for the future development of new antimalarial agents.

Secondary metabolites of Livistona decipiens as potential inhibitors of SARS-CoV-2† † Electronic supplementary information (ESI) available. See https://doi.org/10.1039/d2ra01306a

In late December 2019, a pandemic coronavirus disease 2019 (COVID-19) emerged in Wuhan, China and spread all over the globe. One of the promising therapeutic techniques of viral infection is to search for enzyme inhibitors among natural phytochemicals using molecular docking to obtain leads with the least side effects. The COVID-19 virus main protease (Mpro) is considered as an attractive target due to its pivotal role in controlling viral transcription and replication. Metabolic profiling of the crude extract of Livistona decipiens Becc. (Arecaceae) leaves and fruit dereplicated twelve metabolites using LC-HRESIMS. Molecular docking simulation and in silico ADME profiling of these annotated compounds proposed that tricin is a promising lead against COVID-19 virus Mpro. The alcoholic extract was shown to inhibit SARS-CoV-2 through in vitro culture and RT-PCR testing with EC50 = 0.122 and 1.53 μg mL−1 for leaves and fruit extracts, respectively, when compared with that of the FDA-approved anti-COVID-19 remdesivir (0.002 μg mL−1). Preliminary steps were also performed including the 3CL-protease inhibition assay and cytotoxicity study. It is worthwhile to find a cheap, safe, natural source for promising anti-SARS-CoV-2 agents that can be further tested in vivo against the COVID-19 virus Mpro. This study provides scientific basis for demonstrating beneficial effects of L. decipiens application on human health during the corona pandemic. Promising natural inhibitors for COVID-19.

Secondary metabolites of Livistona decipiens as potential inhibitors of SARS-CoV-2.

In late December 2019, a pandemic coronavirus disease 2019 (COVID-19) emerged in Wuhan, China and spread all over the globe. One of the promising therapeutic techniques of viral infection is to search for enzyme inhibitors among natural phytochemicals using molecular docking to obtain leads with the least side effects. The COVID-19 virus main protease (Mpro) is considered as an attractive target due to its pivotal role in controlling viral transcription and replication. Metabolic profiling of the crude extract of Livistona decipiens Becc. (Arecaceae) leaves and fruit dereplicated twelve metabolites using LC-HRESIMS. Molecular docking simulation and in silico ADME profiling of these annotated compounds proposed that tricin is a promising lead against COVID-19 virus Mpro. The alcoholic extract was shown to inhibit SARS-CoV-2 through in vitro culture and RT-PCR testing with EC50 = 0.122 and 1.53 µg mL-1 for leaves and fruit extracts, respectively, when compared with that of the FDA-approved anti-COVID-19 remdesivir (0.002 µg mL-1). Preliminary steps were also performed including the 3CL-protease inhibition assay and cytotoxicity study. It is worthwhile to find a cheap, safe, natural source for promising anti-SARS-CoV-2 agents that can be further tested in vivo against the COVID-19 virus Mpro. This study provides scientific basis for demonstrating beneficial effects of L. decipiens application on human health during the corona pandemic.

Nature as a treasure trove of potential anti-SARS-CoV drug leads: a structural/mechanistic rationale† † Electronic supplementary information (ESI) available. See DOI: 10.1039/d0ra04199h

The novel Coronavirus disease 2019 (COVID-19) caused by SARS-CoV-2 is a potential factor for fatal illness and a tremendous concern for global public health. The COVID-19 pandemic has entered a dangerous new phase. In the context of drug discovery, the structurally-unique and chemically-diverse natural products have been valuable sources for drug leads. In this review, we report for potential candidates derived from natural sources with well-reported in vitro efficacy against SARS-CoV during the last decade. Additionally, a library of 496 phenolic metabolites was subjected to a computer-aided virtual screening against the active site of the recently reported SARS-CoV Main protease (Mpro). Analysis of physicochemical properties of these natural products has been carried out and presented for all the tested phenolic metabolites. Only three of the top candidates, viz. acetylglucopetunidin (31), isoxanthohumol (32) and ellagic acid (33), which are widely available in many edible fruits, obey both Lipinski's and Veber's rules of drug-likeness and thus possess high degrees of predicted bioavailability. These natural products are suggested as potential drug candidates for the development of anti-SARS-CoV-2 therapeutics in the near future. Potential drug candidates derived from natural sources are posed for the development of anti-SARS CoV-2 therapeutics.

Natural coumarins as potential anti-SARS-CoV-2 agents supported by docking analysis† † Electronic supplementary information (ESI) available. See DOI: 10.1039/d1ra01989a

COVID-19 is a global pandemic first identified in China, causing severe acute respiratory syndrome. One of the therapeutic strategies for combating viral infections is the search for viral spike proteins as attachment inhibitors among natural compounds using molecular docking. This review aims at shedding light on the antiviral potential of natural products belonging to the natural-products class of coumarins up to 2020. Moreover, all these compounds were filtered based on ADME analysis to determine their physicochemical properties, and the best 74 compounds were selected. Using virtual-screening methods, the selected compounds were investigated for potential inhibition of viral main protease (Mpro), viral methyltransferase (nsp16/10 complex), viral recognition binding domain (RBD) of S-protein, and human angiotensin-converting enzyme 2 (ACE2), which is the human receptor for viral S-protein targets, using molecular-docking studies. Promising potential results against SARS-CoV-2 RNA-dependent RNA polymerase (RdRp) and methyltransferase (nsp16) are presented. Potential of coumarins against Covid-19.

Aurasperone A Inhibits SARS CoV-2 In Vitro: An Integrated In Vitro and In Silico Study.

Several natural products recovered from a marine-derived Aspergillus niger were tested for their inhibitory activity against SARS CoV-2 in vitro. Aurasperone A (3) was found to inhibit SARS CoV-2 efficiently (IC50 = 12.25 µM) with comparable activity with the positive control remdesivir (IC50 = 10.11 µM). Aurasperone A exerted minimal cytotoxicity on Vero E6 cells (CC50 = 32.36 mM, SI = 2641.5) and it was found to be much safer than remdesivir (CC50 = 415.22 µM, SI = 41.07). To putatively highlight its molecular target, aurasperone A was subjected to molecular docking against several key-viral protein targets followed by a series of molecular dynamics-based in silico experiments that suggested Mpro to be its primary viral protein target. More potent anti-SARS CoV-2 Mpro inhibitors can be developed according to our findings presented in the present investigation.

Chemical Composition of the Red Sea Green Algae Ulva lactuca: Isolation and In Silico Studies of New Anti-COVID-19 Ceramides.

Coronavirus disease 2019 (COVID-19) is the disease caused by the virus SARS-CoV-2 responsible for the ongoing pandemic which has claimed the lives of millions of people. This has prompted the scientific research community to act to find treatments against the SARS-CoV-2 virus that include safe antiviral medicinal compounds. The edible green algae U. lactuca. is known to exhibit diverse biological activities such as anti-influenza virus, anti-Japanese encephalitis virus, immunomodulatory, anticoagulant, antioxidant and antibacterial activities. Herein, four new ceramides in addition to two known ones were isolated from Ulva lactuca. The isolated ceramides, including Cer-1, Cer-2, Cer-3, Cer-4, Cer-5 and Cer-6 showed promising antiviral activity against SARS-CoV-2 when investigated using in silico approaches by preventing its attachment to human cells and/or inhibiting its viral replication. Cer-4 and Cer-5 were the most effective in inhibiting the human angiotensin converting enzyme (hACE)-spike protein complex which is essential for the virus to enter the human host. In addition to this, Cer-4 also showed an inhibition of the SARS-CoV-2 protease (Mpro) that is responsible for its viral replication and transcription. In this study, we also used liquid chromatography coupled to electrospray ionization high-resolution mass spectroscopy (LC-ESI-HRMS) to identify several metabolites of U. lactuca, including metabolites such as fatty acids, their glyceride derivatives, terpenoids, sterols and oxysterols from the organic extract. Some of these metabolites also possessed promising antiviral activity, as previously reported.

Identifying the specific-targeted marine cerebrosides against SARS-CoV-2: an integrated computational approach.

Cerebrosides are a group of metabolites belonging to the glycosphingolipids class of natural products. So far, 167 cerebrosides, compounds 1-167, have been isolated from diverse marine organisms or microorganisms. The as yet smaller number of compounds that have been studied more in depth proves a potential against challenging diseases, such as cancer, a range of viral and bacterial diseases, as well as inflammation. This review provides a comprehensive summary on this so far under-explored class of compounds, their chemical structures, bioactivities, and their marine sources, with a full coverage to the end of 2020. Today, the global pandemic concern, COVID-19, has claimed millions of death cases around the world, making the development of anti-SARS-CoV-2 drugs urgently needed for such a battle. Accordingly, selected examples from all subclasses of cerebrosides were virtually screened for potential inhibition of SARS-CoV-2 proteins that are crucially involved in the viral-host interaction, viral replication, or in disease progression. The results highlight five cerebrosides that could preferentially bind to the hACE2 protein, with binding scores between -7.1 and -7.6 kcal mol-1 and with the docking poses determined underneath the first α1-helix of the protein. Moreover, the molecular interaction determined by molecular dynamic (MD) simulation revealed that renieroside C1 (60) is more conveniently involved in key hydrophobic interactions with the best stability, least deviation, least ΔG (-6.9 kcal mol-1) and an RMSD value of 3.6 Å. Thus, the structural insights assure better binding affinity and favorable molecular interaction of renieroside C1 (60) towards the hACE2 protein, which plays a crucial role in the biology and pathogenesis of SARS-CoV-2.

Strawberry and Ginger Silver Nanoparticles as Potential Inhibitors for SARS-CoV-2 Assisted by In Silico Modeling and Metabolic Profiling.

SARS-CoV-2 (COVID-19), a novel coronavirus causing life-threatening pneumonia, caused a pandemic starting in 2019 and caused unprecedented economic and health crises all over the globe. This requires the rapid discovery of anti-SARS-CoV-2 drug candidates to overcome this life-threatening pandemic. Strawberry (Fragaria ananassa Duch.) and ginger (Zingiber officinale) methanolic extracts were used for silver nanoparticle (AgNPs) synthesis to explore their SARS-CoV-2 inhibitory potential. Moreover, an in silico study was performed to explore the possible chemical compounds that might be responsible for the anti-SARS-CoV-2 potential. The characterization of the green synthesized AgNPs was carried out with transmission electron microscope (TEM), Fourier-transform infrared, spectroscopy ultraviolet-visible spectroscopy, zeta potential, and a dynamic light-scattering technique. The metabolic profiling of strawberry and ginger methanolic extract was assessed using liquid chromatography coupled with high-resolution mass spectrometry. The antiviral potential against SARS-CoV-2 was evaluated using an MTT assay. Moreover, in silico modeling and the molecular dynamic study were conducted via AutoDock Vina to demonstrate the potential of the dereplicated compounds to bind to some of the SARS-CoV-2 proteins. The TEM analysis of strawberry and ginger AgNPs showed spherical nanoparticles with mean sizes of 5.89 nm and 5.77 nm for strawberry and ginger, respectively. The UV-Visible spectrophotometric analysis showed an absorption peak at λmax of 400 nm for strawberry AgNPs and 405 nm for ginger AgNPs. The Zeta potential values of the AgNPs of the methanolic extract of strawberry was -39.4 mV, while for AgNPs of ginger methanolic extract it was -42.6 mV, which indicates a high stability of the biosynthesized nanoparticles. The strawberry methanolic extract and the green synthesized AgNPs of ginger showed the highest antiviral activity against SARS-CoV-2. Dereplication of the secondary metabolites from the crude methanolic extracts of strawberry and ginger resulted in the annotation of different classes of compounds including phenolic, flavonoids, fatty acids, sesquiterpenes, triterpenes, sterols, and others. The docking study was able to predict the different patterns of interaction between the different compounds of strawberry and ginger with seven SARS-CoV-2 protein targets including five viral proteins (Mpro, ADP ribose phosphatase, NSP14, NSP16, PLpro) and two humans (AAK1, Cathepsin L). The molecular docking and dynamics simulation study showed that neohesperidin demonstrated the potential to bind to both human AAK1 protein and SARS-CoV-2 NSP16 protein, which makes this compound of special interest as a potential dual inhibitor. Overall, the present study provides promise for Anti-SARS-CoV-2 green synthesized AgNPs, which could be developed in the future into a new anti-SARS-CoV-2 drug.

Targeting 3CLpro and SARS-CoV-2 RdRp by Amphimedon sp. Metabolites: A Computational Study.

Since December 2019, novel coronavirus disease 2019 (COVID-19) pandemic has caused tremendous economic loss and serious health problems worldwide. In this study, we investigated 14 natural compounds isolated from Amphimedon sp. via a molecular docking study, to examine their ability to act as anti-COVID-19 agents. Moreover, the pharmacokinetic properties of the most promising compounds were studied. The docking study showed that virtually screened compounds were effective against the new coronavirus via dual inhibition of SARS-CoV-2 RdRp and the 3CL main protease. In particular, nakinadine B (1), 20-hepacosenoic acid (11) and amphimedoside C (12) were the most promising compounds, as they demonstrated good interactions with the pockets of both enzymes. Based on the analysis of the molecular docking results, compounds 1 and 12 were selected for molecular dynamics simulation studies. Our results showed Amphimedon sp. to be a rich source for anti-COVID-19 metabolites.

Natural coumarins as potential anti-SARS-CoV-2 agents supported by docking analysis.

COVID-19 is a global pandemic first identified in China, causing severe acute respiratory syndrome. One of the therapeutic strategies for combating viral infections is the search for viral spike proteins as attachment inhibitors among natural compounds using molecular docking. This review aims at shedding light on the antiviral potential of natural products belonging to the natural-products class of coumarins up to 2020. Moreover, all these compounds were filtered based on ADME analysis to determine their physicochemical properties, and the best 74 compounds were selected. Using virtual-screening methods, the selected compounds were investigated for potential inhibition of viral main protease (Mpro), viral methyltransferase (nsp16/10 complex), viral recognition binding domain (RBD) of S-protein, and human angiotensin-converting enzyme 2 (ACE2), which is the human receptor for viral S-protein targets, using molecular-docking studies. Promising potential results against SARS-CoV-2 RNA-dependent RNA polymerase (RdRp) and methyltransferase (nsp16) are presented.

Natural metabolites from the soft coral Nephthea sp. as potential SARS-CoV-2 main protease inhibitors.

The ongoing spread of SARS-CoV-2 has created a growing need to develop effective antiviral treatments; therefore, this work was undertaken to delve into the natural metabolites of the Red Sea soft coral Nephthea sp. (family Nephtheidae) as a source of potential anti-COVID-19 agents. Overall, a total of 14 structurally diverse minor constituents were isolated and identified from the petroleum ether fraction of Nephthea sp. The characterised compounds were screened and compared for their inhibitory potential against SARS-CoV-2 main protease (Mpro) using Autodock Vina and MOE software. Interestingly, most compounds were able to bind effectively to the active site of Mpro, of which nephthoside monoacetate (1); an acylated tetraprenyltoluquinol glycoside, exhibited the highest binding capacity in both software with comparable interaction energies to the ligand N3 and moderately acceptable drug-likeness properties, which drew attention to the relevance of marine-derived metabolites from Nephthea sp., particularly compound (1), to develop potential SARS-CoV-2 protease inhibitors.

Cnicin as an Anti-SARS-CoV-2: An Integrated In Silico and In Vitro Approach for the Rapid Identification of Potential COVID-19 Therapeutics.

Since the emergence of the SARS-CoV-2 pandemic in 2019, it has remained a significant global threat, especially with the newly evolved variants. Despite the presence of different COVID-19 vaccines, the discovery of proper antiviral therapeutics is an urgent necessity. Nature is considered as a historical trove for drug discovery, especially in global crises. During our efforts to discover potential anti-SARS CoV-2 natural therapeutics, screening our in-house natural products and plant crude extracts library led to the identification of C. benedictus extract as a promising candidate. To find out the main chemical constituents responsible for the extract's antiviral activity, we utilized recently reported SARS CoV-2 structural information in comprehensive in silico investigations (e.g., ensemble docking and physics-based molecular modeling). As a result, we constructed protein-protein and protein-compound interaction networks that suggest cnicin as the most promising anti-SARS CoV-2 hit that might inhibit viral multi-targets. The subsequent in vitro validation confirmed that cnicin could impede the viral replication of SARS CoV-2 in a dose-dependent manner, with an IC50 value of 1.18 µg/mL. Furthermore, drug-like property calculations strongly recommended cnicin for further in vivo and clinical experiments. The present investigation highlighted natural products as crucial and readily available sources for developing antiviral therapeutics. Additionally, it revealed the key contributions of bioinformatics and computer-aided modeling tools in accelerating the discovery rate of potential therapeutics, particularly in emergency times like the current COVID-19 pandemic.

Potential of (Citrus nobilis Lour × Citrus deliciosa Tenora) metabolites on COVID-19 virus main protease supported by in silico analysis.

One of the promising therapeutic strategies for corona virus 2019 (COVID-19) is tolook for enzyme inhibitors. COVID-19 virus main protease (Mpro) plays a vital role in mediating viral transcription and replication, introducing it as an attractive antiviral agent target. LC-ESI-HDMS based metabolic profiling of Citrus nobilis Lour. × Citrus deliciosa Ten. (Rutaceae) annotated 21 compounds belonging to diverse classes. Molecular docking studies were carried out to ascertain the inhibitory action of studied dereplicated compounds through the interactions within the active site of SARS-CoV-2 (Mpro). Among which, quercetin-7-O-glucoside-3-O-rutinoside (21) possessed the best binding affinity (-9.47 kcal/mol), followed by luteoline-7-rutinoside (18), quercetin-3-O-rutinoside (19) and apigenin-8-C-glucoside (15) showed less binding affinities ranging at -8.27, -7.97 and -6.94 kcal/mol respectively.

Inhibition of SARS-CoV-2 main protease by phenolic compounds from Manilkara hexandra (Roxb.) Dubard assisted by metabolite profiling and in silico virtual screening.

SARS-CoV-2 is a novel coronavirus that was first identified during the outbreak in Wuhan, China in 2019. It is an acute respiratory illness that can transfer among human beings. Natural products can provide a rich resource for novel antiviral drugs. They can interfere with viral proteins such as viral proteases, polymerases, and entry proteins. Several naturally occurring flavonoids were reported to have antiviral activity against different types of RNA and DNA viruses. A methanolic extract of Manilkara hexandra (Roxb.) Dubard leaves is rich in phenolic compounds, mainly flavonoids. Metabolic profiling of the secondary metabolites of Manilkara hexandra (Roxb.) Dubard leaves methanolic extract (MLME), and bark ethyl acetate (MBEE) extract using LC-HRESIMS resulted in the isolation of 18 compounds belonging to a variety of constituents, among which phenolic compounds, flavones, flavonol glycosides and triterpenes were predominant. Besides, four compounds (I-IV) were isolated and identified as myricetin I, myricitrin II, mearnsitrin III, and mearnsetin-3-O-ß-d-rutinoside IV (compound IV is isolated for the first time from genus Manilkara) and dereplicated in a metabolomic study as compounds 3, 5, 6, and 12, respectively. The molecular docking study showed that rutin, myricitrin, mearnsitrin, and quercetin 3-O-ß-d-glucoside have strong interaction with SARS-CoV-2 protease with high binding energy of -8.2072, -7.1973, -7.5855, and -7.6750, respectively. Interestingly, the results proved that rutin which is a citrus flavonoid glycoside exhibits the strongest inhibition effect to the SARS-CoV-2 protease enzyme. Consequently, it can contribute to developing an effective antiviral drug lead against the SARS-CoV-2 pandemic.

Metabolomic profiling of three Araucaria species, and their possible potential role against COVID-19.

The COVID-19 pandemic in Egypt is a part of the worldwide global crisis of coronavirus 2 (SARS-CoV-2). The contagious life-threatening condition causes acute respiratory syndrome. The present study aimed to assess the compounds identified by LC-MS of the methanolic leaves extracts from three conifers trees cultivated in Egypt (Araucaria bidwillii, Araucaria. cunninghamii and Araucaria heterophylla) via docking technique as potential inhibitor of COVID-19 virus on multiple targets; viral main protease (Mpro, 6LU7), non-structural protein-16 which is a methyl transferase (nsp16, 6W4H) and RNA dependent RNA polymerase (nsp12, 7BV2). Among the three targets, nsp16 was the best target recognized by the tested compounds as can be deduced from docking studies. Moreover, the methanolic extract of A. cunninghamii showed the highest radical-scavenging activity using (DPPH test) with 53.7 µg/mL comparable to ascorbic acid with IC50 = 46 µg/mL The anti-inflammatory potential carried using enzyme linked immunoassay showed the highest activity for A. cunninghamii and A. bidwillii followed by A. heterophylla with IC50 = 23.20 ± 1.17 µg/mL, 82.83 ± 3.21 µg/mL and 221.13 ± 6.7 µg/mL, respectively (Celecoxib was used as a standard drug with IC50 = 141.92 ± 4.52 µg/mL). Moreover, a molecular docking study was carried for the LC-MS annotated metabolites to validate their anti-inflammatory inhibitory effect using Celecoxib as a reference compound and showed a high docking score (-7.7 kcal/mol) for Octadecyl (E) P-coumarate and (-7.3 kcal/mol) for secoisolariciresinol rhamnoside.Communicated by Ramaswamy H. Sarma.

Multitarget in silico studies of Ocimum menthiifolium, family Lamiaceae against SARS-CoV-2 supported by molecular dynamics simulation.

The novel strain of human coronavirus, emerged in December 2019, which has been designated as SARS-CoV-2, causes a severe acute respiratory syndrome. Since then, it has arisen as a serious threat to the world public health. Since no approved vaccines or drugs has been found to efficiently stop the virulent spread of the virus, progressive inquiries targeting these viruses are urgently needed, especially those from plant sources. Metabolic profiling using LC-HR-ESI-MS of the butanol extract of Ocimum menthiifolium (Lamiaceae) aerial parts yielded 10 compounds including flavonoids, iridoids and phenolics. As it has been previously reported that some flavonoids can be used as anti-SARS drugs by targeting SARS-CoV-1 3CLpro, we chose to examine 14 flavonoids (detected by metabolomics and other compounds isolated via several chromatographic techniques). We investigated their potential binding interactions with the 4 main SARS-CoV-2 targets: Mpro, nsp16/nsp10 complex, ACE2-PD and RBD-S-protein via molecular docking. Docking results indicated that the nsp16/nsp10 complex has the best binding affinities where the strongest binding was detected with apigenin-7-O-rutinoside, prunin and acaciin with -9.4, -9.3 and -9.3 kcal/mol binding energy, respectively, compared to the control (SAM) with -8.2 kcal/mol. Furthermore, the stability of these complexes was studied using molecular dynamics of 150 ns, which were then compared to their complexes in the other three targets. MM-PBSA calculations suggested the high stability of acaciin-nsp16 complex with binding energy of -110 kJ/mol. This study sheds light on the structure-based design of natural flavonoids as anti-SARS-CoV-2 drugs targeting the nsp16/10 complex.Communicated by Ramaswamy H. Sarma.