In silico screening of FDA approved drugs against ACE2 receptor: potential therapeutics to inhibit the entry of SARS-CoV-2 to human cells.

An unknown coronavirus that emerged sometime at the end of 2019 in China, the novel SARS-CoV-2, now called COVID-19, has spread all over the world. Several efforts have been made to prevent or treat this disease, though not with success. The initiation of COVID-19 viral infection involves specific binding of SARS-CoV-2 to the host surface of the receptor, ACE2. The ACE2- SARS-CoV-2 complex then gets transferred into the endosomes where the endosomal acidic proteases cleave the S protein present in SARS-CoV-2, activating its fusion and release of the viral genome. We have carried out detailed and thorough in silico studies to repurpose FDA approved compounds to inhibit human ACE2 receptor so as to prevent the viral entry. Our study reveals that five compounds show good binding to the ACE2 receptor and hence are potential candidates to interact with ACE2 and prevent it's recognition by the virus, SARS-CoV-2. Communicated by Ramaswamy H. Sarma.

Epicatechin is a promising novel inhibitor of SARS-CoV-2 entry by disrupting interactions between angiotensin-converting enzyme type 2 and the viral receptor binding domain: A computational/simulation study.

Angiotensin-converting enzyme 2 (ACE2) is the first target of SARS-CoV-2 and a key functional host receptor through which this virus hooks into and infects human cells. The necessity to block this receptor is one of the essential means to prevent the outbreak of COVID-19. This study was conducted to determine the most eligible natural compound to suppress ACE2 to counterfeit its interaction with the viral infection. To do this, the most known compounds of sixty-six Iraqi medicinal plants were generated and retrieved from PubChem database. After preparing a library for Iraqi medicinal plants, 3663 unique ligands' conformers were docked to ACE2 using the GLIDE tool. Results found that twenty-three compounds exhibited the highest binding affinity with ACE2. The druglikeness and toxicity potentials of these compounds were evaluated using SwissADME and Protox servers respectively. Out of these virtually screened twenty-three compounds, epicatechin and kempferol were predicted to exert the highest druglikeness and lowest toxicity potentials. Extended Molecular dynamics (MD) simulations showed that ACE2-epicatechin complex exhibited a slightly higher binding stability than ACE2-kempferol complex. In addition to the well-known ACE2 inhibitors that were identified in previous studies, this study revealed for the first time that epicatechin from Hypericum perforatum provided a better static and dynamic inhibition for ACE2 with highly favourable pharmacokinetic properties than the other known ACE2 inhibiting compounds. This study entailed the ability of epicatechin to be used as a potent natural inhibitor that can be used to block or at least weaken the SARS-CoV-2 entry and its subsequent invasion. In vitro experiments are required to validate epicatechin effectiveness against the activity of the human ACE2 receptor.

Screening of potential spike glycoprotein / ACE2 dual antagonists against COVID-19 in silico molecular docking.

The novel coronavirus disease has spread rapidly and caused sustained pressure on economic and medical resources to many countries. Vaccines and effective drugs are needed to fight against the epidemic. Traditional Chinese Medicine (TCM) plays an important and effective role in the treatment of COVID-19. Therefore, the active components of TCM are potential structural basis for the discovery of antiviral drugs. Through screening by molecular docking, Oleanolic acid, Tryptanthrin, Chrysophanol and Rhein were found to have better spike protein and ACE2 inhibitory activity, which could block the invasion and recognition of SARS-CoV-2 at the same time, should be investigated as antiviral candidates.

Virtual Screening in Search for a Chemical Probe for Angiotensin-Converting Enzyme 2 (ACE2).

We elaborate new models for ACE and ACE2 receptors with an excellent prediction power compared to previous models. We propose promising workflows for working with huge compound collections, thereby enabling us to discover optimized protocols for virtual screening management. The efficacy of elaborated roadmaps is demonstrated through the cost-effective molecular docking of 1.4 billion compounds. Savings of up to 10-fold in CPU time are demonstrated. These developments allowed us to evaluate ACE2/ACE selectivity in silico, which is a crucial checkpoint for developing chemical probes for ACE2.

Effect of Morus alba leaf extract dose on lipid oxidation, microbiological stability, and sensory evaluation of functional liver pâtés during refrigerated storage.

Mulberry (Morus alba L.), and above all the extract from the leaves of this plant, is a natural medicine that has been used in traditional medicine for hundreds of years. Mulberry leaves contains polyphenol compounds: flavonoids, coumarins, numerous phenolic acids, as well as terpenes and steroids. The antioxidant effect of these compounds may be beneficial to the fat fraction of meat products, thereby increasing their functional qualities. The aim of the study was to evaluate the effectiveness of the use of mulberry water leaf extract, as an additive limiting adverse fat changes and affecting the functionality in model liver pâtés. Pork pâtés were prepared by replacing 20% of animal fat with rapeseed oil (RO), and water extract of mulberry leaves was added in the proportion of 0.2%, 0.6% and 1.0%. It has been shown that the addition of mulberry leaf extract delayed the appearance of primary and secondary fat oxidation products. The most effective antioxidant effect during 15-day storage was observed in the sample with the addition of 0.6% and 1.0% water mulberry leaf extract. These samples also showed inhibiting activity against angiotensin-converting enzymes and cholinesterase's. During storage, the tested pâtés had a high sensory quality with unchanged microbiological quality. Mulberry leaf extract can be an interesting addition to the production of fat meat products, delaying adverse changes in the lipid fraction and increasing the functionality of products.

Jeopardy of COVID-19: Rechecking the Perks of Phytotherapeutic Interventions.

The novel coronavirus disease (COVID-19), the reason for worldwide pandemic, has already masked around 220 countries globally. This disease is induced by Severe Acute Respiratory Syndrome-Coronavirus-2 (SARS-CoV-2). Arising environmental stress, increase in the oxidative stress level, weak immunity and lack of nutrition deteriorates the clinical status of the infected patients. Though several researches are at its peak for understanding and bringing forward effective therapeutics, yet there is no promising solution treating this disease directly. Medicinal plants and their active metabolites have always been promising in treating many clinical complications since time immemorial. Mother nature provides vivid chemical structures, which act multi-dimensionally all alone or synergistically in mitigating several diseases. Their unique antioxidant and anti-inflammatory activity with least side effects have made them more effective candidate for pharmacological studies. These medicinal plants inhibit attachment, encapsulation and replication of COVID-19 viruses by targeting various signaling molecules such as angiotensin converting enzyme-2, transmembrane serine protease 2, spike glycoprotein, main protease etc. This property is re-examined and its potency is now used to improve the existing global health crisis. This review is an attempt to focus various antiviral activities of various noteworthy medicinal plants. Moreover, its implications as prophylactic or preventive in various secondary complications including neurological, cardiovascular, acute kidney disease, liver disease are also pinpointed in the present review. This knowledge will help emphasis on the therapeutic developments for this novel coronavirus where it can be used as alone or in combination with the repositioned drugs to combat COVID-19.

Spike protein recognizer receptor ACE2 targeted identification of potential natural antiviral drug candidates against SARS-CoV-2.

Angiotensin-converting enzyme 2 (ACE2), also known as peptidyl-dipeptidase A, belongs to the dipeptidyl carboxydipeptidases family has emerged as a potential antiviral drug target against SARS-CoV-2. Most of the ACE2 inhibitors discovered till now are chemical synthesis; suffer from many limitations related to stability and adverse side effects. However, natural, and selective ACE2 inhibitors that possess strong stability and low side effects can be replaced instead of those chemicals' inhibitors. To envisage structurally diverse natural entities as an ACE2 inhibitor with better efficacy, a 3D structure-based-pharmacophore model (SBPM) has been developed and validated by 20 known selective inhibitors with their correspondence 1166 decoy compounds. The validated SBPM has excellent goodness of hit score and good predictive ability, which has been appointed as a query model for further screening of 11,295 natural compounds. The resultant 23 hits compounds with pharmacophore fit score 75.31 to 78.81 were optimized using in-silico ADMET and molecular docking analysis. Four potential natural inhibitory molecules namely D-DOPA (Amb17613565), L-Saccharopine (Amb6600091), D-Phenylalanine (Amb3940754), and L-Mimosine (Amb21855906) have been selected based on their binding affinity (-7.5, -7.1, -7.1, and -7.0 kcal/mol), respectively. Moreover, 250 ns molecular dynamics (MD) simulations confirmed the structural stability of the ligands within the protein. Additionally, MM/GBSA approach also used to support the stability of molecules to the binding site of the protein that also confirm the stability of the selected four natural compounds. The virtual screening strategy used in this study demonstrated four natural compounds that can be utilized for designing a future class of potential natural ACE2 inhibitor that will block the spike (S) protein dependent entry of SARS-CoV-2 into the host cell.

Food Enrichment with Glycyrrhiza glabra Extract Suppresses ACE2 mRNA and Protein Expression in Rats-Possible Implications for COVID-19.

Angiotensin converting enzyme 2 (ACE2) is a key entry point of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus known to induce Coronavirus disease 2019 (COVID-19). We have recently outlined a concept to reduce ACE2 expression by the administration of glycyrrhizin, a component of Glycyrrhiza glabra extract, via its inhibitory activity on 11beta hydroxysteroid dehydrogenase type 2 (11betaHSD2) and resulting activation of mineralocorticoid receptor (MR). We hypothesized that in organs such as the ileum, which co-express 11betaHSD2, MR and ACE2, the expression of ACE2 would be suppressed. We studied organ tissues from an experiment originally designed to address the effects of Glycyrrhiza glabra extract on stress response. Male Sprague Dawley rats were left undisturbed or exposed to chronic mild stress for five weeks. For the last two weeks, animals continued with a placebo diet or received a diet containing extract of Glycyrrhiza glabra root at a dose of 150 mg/kg of body weight/day. Quantitative PCR measurements showed a significant decrease in gene expression of ACE2 in the small intestine of rats fed with diet containing Glycyrrhiza glabra extract. This effect was independent of the stress condition and failed to be observed in non-target tissues, namely the heart and the brain cortex. In the small intestine we also confirmed the reduction of ACE2 at the protein level. Present findings provide evidence to support the hypothesis that Glycyrrhiza glabra extract may reduce an entry point of SARS-CoV-2. Whether this phenomenon, when confirmed in additional studies, is linked to the susceptibility of cells to the virus requires further studies.

COVID-19 Infection: Targeting Possibilities for Treatment.

The outbreak of novel coronavirus (nCoV) or severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) in December 2019 in Wuhan, China, has posed an international public health emergency worldwide and forced people to be confined in their homes. This virus is of high-risk category and is declared a pandemic by the World Health Organization (WHO). The worldwide researchers and various health professionals are working together to determine the best way to stop its spread or halt this virus's spread and circumvent this pandemic condition threatening millions of human lives. The absence of definitive treatment is possible to explore to reduce virus infection and enhance patient recovery. Along with off-label medicines, plasma therapy, vaccines, the researchers exploit the various plants/herbs and their constituents to effectively treat nCoV infection. The present study aimed to present brief and most informative salient features of the numerous facts regarding the SARS-CoV-2, including the structure, genomic sequence, recent mutation, targeting possibility, and various hurdles in research progress, and off-labeled drugs, convalescent plasma therapy, vaccine and plants/herbs for the treatment of coronavirus disease-2019 (COVID-19). Results showed that off-labeled drugs such as hydroxychloroquine, dexamethasone, tocilizumab, antiviral drug (remdesivir, favipiravir), etc., give positive results and approved for use or approved for restricted use in some countries like India. Future research should focus on these possibilities that may allow the development of an effective treatment for COVID-19.

Identification of natural compounds as SARS-CoV-2 entry inhibitors by molecular docking-based virtual screening with bio-layer interferometry.

Coronavirus Disease 2019 (COVID-19) is caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), which enter the host cells through the interaction between its receptor binding domain (RBD) of spike glycoprotein with angiotensin-converting enzyme 2 (ACE2) receptor on the plasma membrane of host cell. Neutralizing antibodies and peptide binders of RBD can block viral infection, however, the concern of accessibility and affordability of viral infection inhibitors has been raised. Here, we report the identification of natural compounds as potential SARS-CoV-2 entry inhibitors using the molecular docking-based virtual screening coupled with bilayer interferometry (BLI). From a library of 1871 natural compounds, epigallocatechin gallate (EGCG), 20(R)-ginsenoside Rg3 (RRg3), 20(S)-ginsenoside Rg3 (SRg3), isobavachalcone (Ibvc), isochlorogenic A (IscA) and bakuchiol (Bkc) effectively inhibited pseudovirus entry at concentrations up to 100 µM. Among these compounds, four compounds, EGCG, Ibvc, salvianolic acid A (SalA), and isoliensinine (Isl), were effective in inhibiting SARS-CoV-2-induced cytopathic effect and plaque formation in Vero E6 cells. The EGCG was further validated with no observable animal toxicity and certain antiviral effect against SARS-CoV-2 pseudovirus mutants (D614G, N501Y, N439K & Y453F). Interestingly, EGCG, Bkc and Ibvc bind to ACE2 receptor in BLI assay, suggesting a dual binding to RBD and ACE2. Current findings shed some insight into identifications and validations of SARS-CoV-2 entry inhibitors from natural compounds.

Inhibiting SARS-CoV-2 infection in vitro by suppressing its receptor, angiotensin-converting enzyme 2, via aryl-hydrocarbon receptor signal.

Since understanding molecular mechanisms of SARS-CoV-2 infection is extremely important for developing effective therapies against COVID-19, we focused on the internalization mechanism of SARS-CoV-2 via ACE2. Although cigarette smoke is generally believed to be harmful to the pathogenesis of COVID-19, cigarette smoke extract (CSE) treatments were surprisingly found to suppress the expression of ACE2 in HepG2 cells. We thus tried to clarify the mechanism of CSE effects on expression of ACE2 in mammalian cells. Because RNA-seq analysis suggested that suppressive effects on ACE2 might be inversely correlated with induction of the genes regulated by aryl hydrocarbon receptor (AHR), the AHR agonists 6-formylindolo(3,2-b)carbazole (FICZ) and omeprazole (OMP) were tested to assess whether those treatments affected ACE2 expression. Both FICZ and OMP clearly suppressed ACE2 expression in a dose-dependent manner along with inducing CYP1A1. Knock-down experiments indicated a reduction of ACE2 by FICZ treatment in an AHR-dependent manner. Finally, treatments of AHR agonists inhibited SARS-CoV-2 infection into Vero E6 cells as determined with immunoblotting analyses detecting SARS-CoV-2 specific nucleocapsid protein. We here demonstrate that treatment with AHR agonists, including FICZ, and OMP, decreases expression of ACE2 via AHR activation, resulting in suppression of SARS-CoV-2 infection in mammalian cells.

Investigation of potential inhibitor properties of ethanolic propolis extracts against ACE-II receptors for COVID-19 treatment by molecular docking study.

The angiotensin-converting enzyme (ACE)-related carboxypeptidase, ACE-II, is a type I integral membrane protein of 805 amino acids that contains 1 HEXXH-E zinc binding consensus sequence. ACE-II has been implicated in the regulation of heart function and also as a functional receptor for the coronavirus that causes the severe acute respiratory syndrome (SARS). In this study, the potential of some flavonoids presents in propolis to bind to ACE-II receptors was calculated with in silico. Binding constants of ten flavonoids, caffeic acid, caffeic acid phenethyl ester, chrysin, galangin, myricetin, rutin, hesperetin, pinocembrin, luteolin and quercetin were measured using the AutoDock 4.2 molecular docking program. And also, these binding constants were compared to reference ligand of MLN-4760. The results are shown that rutin has the best inhibition potentials among the studied molecules with high binding energy - 8.04 kcal/mol, and it is followed by myricetin, quercetin, caffeic acid phenethyl ester and hesperetin. However, the reference molecule has binding energy of - 7.24 kcal/mol. In conclusion, the high potential of flavonoids in ethanolic propolis extracts to bind to ACE-II receptors indicates that this natural bee product has high potential for COVID-19 treatment, but this needs to be supported by experimental studies.

Network-Based Analysis of Fatal Comorbidities of COVID-19 and Potential Therapeutics.

COVID-19 is a highly contagious disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The case-fatality rate is significantly higher in older patients and those with diabetes, cancer or cardiovascular disorders. The human proteins, angiotensin-converting enzyme 2 (ACE2), transmembrane protease serine 2 (TMPRSS2) and basigin (BSG), are involved in high-confidence host-pathogen interactions with SARS-CoV-2 proteins. We considered these three proteins as seed nodes and applied the random walk with restart method on the human interactome to construct a protein-protein interaction sub-network, which captures the effects of viral invasion. We found that 'Insulin resistance', 'AGE-RAGE signaling in diabetic complications' and 'adipocytokine signaling' were the common pathways associated with diabetes, cancer and cardiovascular disorders. The association of these critical pathways with aging and its related diseases explains the molecular basis of COVID-19 fatality. We further identified drugs that have effects on these proteins/pathways based on gene expression studies. We particularly focused on drugs that significantly downregulate ACE2 along with other critical proteins identified by the network-based approach. Among them, COL-3 had earlier shown activity against acute lung injury and acute respiratory distress, while entinostat and mocetinostat have been investigated for non-small-cell lung cancer. We propose that these drugs can be repurposed for COVID-19.

Potential effect of Maxing Shigan decoction against coronavirus disease 2019 (COVID-19) revealed by network pharmacology and experimental verification.

ETHNOPHARMACOLOGICAL RELEVANCE: Since the occurrence of coronavirus disease 2019 (COVID-19) in Wuhan, China in December 2019, COVID-19 has been quickly spreading out to other provinces and countries. Considering that traditional Chinese medicine (TCM) played an important role during outbreak of SARS and H1N1, finding potential alternative approaches for COVID-19 treatment is necessary before vaccines are developed. According to previous studies, Maxing Shigan decoction (MXSGD) present a prominent antivirus effect and is often used to treat pulmonary diseases. Furthermore, we collected 115 open prescriptions for COVID-19 therapy from the National Health Commission, State Administration of TCM and other organizations, MXSGD was identified as the key formula. However, the underlying molecular mechanism of MXSGD against COVID-19 is still unknown. AIM OF THE STUDY: The present study aimed to evaluate the therapeutic mechanism of MXSGD against COVID-19 by network pharmacology and in vitro experiment verification, and screen the potential components which could bind to key targets of COVID-19 via molecular docking method. MATERIALS AND METHODS: Multiple open-source databases related to TCM or compounds were employed to screen active ingredients and potential targets of MXSGD. Network pharmacology analysis methods were used to initially predict the antivirus and anti-inflammatory effects of MXSGD against COVID-19. IL-6 induced rat lung epithelial type Ⅱ cells (RLE-6TN) damage was established to explore the anti-inflammatory damage activity of MXSGD. After MXSGD intervention, the expression level of related proteins and their phosphorylation in the IL-6 mediated JAK-STAT signaling pathway were detected by Western blot. Molecular docking technique was used to further identify the potential substances which could bind to three key targets (ACE2, Mpro and RdRp) of COVID-19. RESULTS: In this study, 105 active ingredients and 1025 candidate targets were selected for MXSGD, 83 overlapping targets related to MXSGD and COVID-19 were identified, and the protein-protein interaction (PPI) network of MXSGD against COVID-19 was constructed. According to the results of biological enrichment analysis, 63 significant KEGG pathways were enriched, and most of them were related to signal transduction, immune system and virus infection. Furthermore, according the relationship between signal pathways, we confirmed MXSGD could effectively inhibit IL-6 mediated JAK-STAT signal pathway related protein expression level, decreased the protein expression levels of p-JAK2, p-STAT3, Bax and Caspase 3, and increased the protein expression level of Bcl-2, thereby inhibiting RLE-6TN cells damage. In addition, according to the LibDock scores screening results, the components with strong potential affinity (Top 10) with ACE2, Mpro and RdRp are mainly from glycyrrhiza uralensis (Chinese name: Gancao) and semen armeniacae amarum (Chinese name: Kuxingren). Among them, amygdalin was selected as the optimal candidate component bind to all three key targets, and euchrenone, glycyrrhizin, and glycyrol also exhibited superior affinity interactions with ACE2, Mpro and RdRp, respectively. CONCLUSION: This work explained the positive characteristics of multi-component, multi-target, and multi-approach intervention with MXSGD in combating COVID-19, and preliminary revealed the antiviral and anti-inflammatory pharmacodynamic substances and mechanism of MXSGD, which might provide insights into the vital role of TCM in the prevention and treatment of COVID-19.

An Updated Review on Betacoronavirus Viral Entry Inhibitors: Learning from Past Discoveries to Advance COVID-19 Drug Discovery.

Even after one year of its first outbreak reported in China, the coronavirus disease 2019 (COVID-19) pandemic is still sweeping the World, causing serious infections and claiming more fatalities. COVID-19 is caused by the novel coronavirus SARS-CoV-2, which belongs to the genus Betacoronavirus (ß-CoVs), which is of greatest clinical importance since it contains many other viruses that cause respiratory disease in humans, including OC43, HKU1, SARS-CoV, and MERS. The spike (S) glycoprotein of ß-CoVs is a key virulence factor in determining disease pathogenesis and host tropism, and it also mediates virus binding to the host's receptors to allow viral entry into host cells, i.e., the first step in virus lifecycle. Viral entry inhibitors are considered promising putative drugs for COVID-19. Herein, we mined the biomedical literature for viral entry inhibitors of other coronaviruses, with special emphasis on ß-CoVs entry inhibitors. We also outlined the structural features of SARS-CoV-2 S protein and how it differs from other ß-CoVs to better understand the structural determinants of S protein binding to its human receptor (ACE2). This review highlighted several promising viral entry inhibitors as potential treatments for COVID-19.

Drug screening and development from the affinity of S protein of new coronavirus with ACE2.

Recently, various studies have shown that angiotensin-converting enzyme 2 (ACE2) acts as the "doorknob" that can be bound by the spike protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which conduces to its entrance to the host cells, and plays an important role in corona virus disease 2019 (COVID-19). This paper aims to collect and sorts out the existing drugs, which exert the ability to block the binding of S protein and ACE2 so as to provide directions for the later drug development. By reviewing the existing literature, we expound the pathogenesis of SARS-CoV-2 from the perspective of S protein and ACE2 binding, and summarize the drugs and compounds that can interfere with the interaction of spike protein and ACE2 receptor from different ways. We summarized five kinds of substances, including peptide P6, griffithsin, hr2p analogs, EK1, vaccine, monoclonal antibody, cholesterol-depleting agents, and extracts from traditional Chinese medicine. They can fight SARS-CoV-2 by specifically binding to ACE2 receptor, S protein, or blocking membrane fusion between the host and virus. ACE2 is the key point for SARS-CoV-2 to enter the cells, and it is also the focus of drug intervention. Our drug summary on this pathomechanism is expected to provide ideas for the drug research on SARS-CoV-2 and help to develop anti-coronavirus drugs of broad spectrum for future epidemics.

Screened antipsychotic drugs inhibit SARS-CoV-2 binding with ACE2 in vitro.

AIM: The coronavirus disease 2019 (COVID-19) pandemic has swept the globe and no specific effective drug has been identified. Drug repurposing is a well-known method to address the crisis in a time-critical fashion. Antipsychotic drugs (APDs) have been reported to inhibit DNA replication of hepatitis B virus, measles virus germination, and HIV infection, along with replication of SARS-CoV and MERS-CoV, both of which interact with host cells as SARS-CoV-2. METHODS: Nineteen APDs were screened using ACE2-HEK293T cell membrane chromatography (ACE2-HEK293T/CMC). Cytotoxicity assay, coronavirus spike pseudotype virus entry assay, surface plasmon resonance, and virtual molecular docking were applied to detect affinity between ACE2 protein and drugs and a potential antiviral property of the screened compounds. KEY FINDINGS: After the CMC screening, 8 of the 19 APDs were well-retained on ACE2-HEK293T/CMC column and showed significant antiviral activities in vitro. Three quarters of them belong to phenothiazine and could significantly inhibit the entrance of coronavirus into ACE2-HEK293T cells. Aother two drugs, aripiprazole and tiapride, exhibited weaker inhibition. We selected five of the drugs for subsequent evaluation. All five showed similar affinity to ACE2 and virtual molecular docking demonstrated they bound with different amino acids respectively on ACE2 which SARS-CoV-2 binds to. SIGNIFICANCE: Eight APDs were screened for binding with ACE2, five of which demonstrated potential protective effects against SARS-CoV-2 through acting on ACE2. Although the five drugs have a weak ability to block SARS-CoV-2 with a single binding site, they may provide a synergistic effect in adjuvant therapy of COVID-19 infection.

Phytopharmaceuticals mediated Furin and TMPRSS2 receptor blocking: can it be a potential therapeutic option for Covid-19?

BACKGROUND: Currently, novel coronavirus disease (Covid-19) outbreak creates global panic across the continents, as people from almost all countries and territories have been affected by this highly contagious viral disease. The scenario is deteriorating due to lack of proper & specific target-oriented pharmacologically safe prophylactic agents or drugs, and or any effective vaccine. drug development is urgently required to back in the normalcy in the community and to combat this pandemic. PURPOSE: Thus, we have proposed two novel drug targets, Furin and TMPRSS2, as Covid-19 treatment strategy. We have highlighted this target-oriented novel drug delivery strategy, based on their pathophysiological implication on SARS-CoV-2 infection, as evident from earlier SARS-CoV-1, MERS, and influenza virus infection via host cell entry, priming, fusion, and endocytosis. STUDY DESIGN &  METHODS: An earlier study suggested that Furin and TMPRSS2 knockout mice had reduced level of viral load and a lower degree of organ damage such as the lung. The present study thus highlights the promise of some selected novel and potential anti-viral Phytopharmaceutical that bind to Furin and TMPRSS2 as target. RESULT: Few of them had shown promising anti-viral response in both preclinical and clinical study with acceptable therapeutic safety-index. CONCLUSION: Hence, this strategy may limit life-threatening Covid-19 infection and its mortality rate through nano-suspension based intra-nasal or oral nebulizer spray, to treat mild to moderate SARS-COV-2 infection when Furin and TMPRSS2 receptor may initiate to express and activate for processing the virus to cause cellular infection by replication within the host cell and blocking of host-viral interaction.

Therapeutic Approach against 2019-nCoV by Inhibition of ACE-2 Receptor.

The continued spread of 2019-nCoV has prompted widespread concern around the world. WHO formally named COVID-19 and International Committee on Taxonomy called it Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2). Due to this viral attack, the whole world is in lockdown. Presently, there is no effective way to control it, except social distancing and hygienic activity. World class scientists and researchers are trying to make vaccine and discover the medicine against the control and cure to this deadly viral disease. Our aim to presenting this article is kick-off deadly viral disease i.e COVID-19 by an easy way with minimum intervention and effort. Different ayurvedic therapeutic agents (Curcuma Longa L, Green tea and Piper nigrum) inhabit entry of virus in host cell, transmission of pathogen and improve the immunity. Curcumin and piperine (1-piperoylpiperidine) interact to each other and form a π-π intermolecular complex which enhance the bioavailability of curcumin by inhibition of glucuronidation of curcumin in liver. Both the molecules curcumin and catechin get bound directly to receptors binding domain of S-protein and ACE-2 receptors of host cell, due to which these molecules inhibit the entry of virus in host cell i. e. animal survives from being infected.

Structural Variability, Expression Profile, and Pharmacogenetic Properties of TMPRSS2 Gene as a Potential Target for COVID-19 Therapy.

The human serine protease serine 2 TMPRSS2 is involved in the priming of proteins of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and represents a possible target for COVID-19 therapy. The TMPRSS2 gene may be co-expressed with SARS-CoV-2 cell receptor genes angiotensin-converting enzyme 2 (ACE2) and Basigin (BSG), but only TMPRSS2 demonstrates tissue-specific expression in alveolar cells according to single-cell RNA sequencing data. Our analysis of the structural variability of the TMPRSS2 gene based on genome-wide data from 76 human populations demonstrates that a functionally significant missense mutation in exon 6/7 in the TMPRSS2 gene is found in many human populations at relatively high frequencies, with region-specific distribution patterns. The frequency of the missense mutation encoded by rs12329760, which has previously been found to be associated with prostate cancer, ranged between 10% and 63% and was significantly higher in populations of Asian origin compared with European populations. In addition to single-nucleotide polymorphisms, two copy number variants were detected in the TMPRSS2 gene. A number of microRNAs have been predicted to regulate TMPRSS2 and BSG expression levels, but none of them is enriched in lung or respiratory tract cells. Several well-studied drugs can downregulate the expression of TMPRSS2 in human cells, including acetaminophen (paracetamol) and curcumin. Thus, the interactions of TMPRSS2 with SARS-CoV-2, together with its structural variability, gene-gene interactions, expression regulation profiles, and pharmacogenomic properties, characterize this gene as a potential target for COVID-19 therapy.