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Background: As the COVID era unfolds, researchers reveal that rapid changes in viral genetic material allow viruses to circumvent challenges triggered by the host immune system and resist anti-viral drugs, potentially leading to persistent viral manifestations in host cells. Molnupiravir (RNA-dependent RNA polymerase inhibitor) is a novel anti-viral medicine promising a vital role in coming setbacks.Objectives: This review aims to clarify the safety and efficacy of the molnupiravir molecule in light of existing case studies. As a result, it is intended to explore and discuss the molecular structure, mechanism of action, discovery and development process, preclinical research, clinical investigations, and other subtopics.Methods: A total of 75 publications were searched using multiple engines, such as Google Scholar, PubMed, Web of Science, Embase, Cochrane Library, ClinicalTrials.gov, and others, with a constraint applied to exclude publications published over 11 years ago. Molnupiravir, safety, efficacy, COVID- 19, RdRp, PK-PD, and clinical study were utilized as keywords.Results: Clinical results on molnupiravir are supported by investigations that were recently disclosed in a study on both sex volunteers (male and female) with an age restriction of 19 to 60 years, followed by a Phase-3 Clinical Trial (NCT04575584) with 775 randomly assigned participants and no fatalities reported due to treatment.Conclusion: Molnupiravir proved a high level of safety, allowing it to be tested further. This review supports the safety and efficacy of this molecule based on the established evidence, which claims the most anticipated employment of molnupiravir in COVID protocol.
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Background: The deadly virus COVID-19 has affected more than 1 crore people and claimed more than 5 lakh lives worldwide according to the World health organization. Though there are numerous treatment modalities available including anti-bacterials, antivirals, vaccines etc., none of them can be considered as effective cure for SARS CoV-2 virus as they are mostly non-specific in action. Aim(s): siRNA therapy can be considered as a significant treatment modality due to its specificity in action. The aim of this review is to explore siRNA as a potential treatment strategy for the treatment of COVID-19. Material(s) and Method(s): In this review we shall explore the targets of siRNA therapy which includes viral RNA-dependent RNA polymerase, helicase, protease and nucleoprotein N. siRNA related patents provide solutions for novel RNAi techniques, high expense of chemically synthetic siRNA, techniques for restraining SARS-CoV by disturbing RNA etc., siRNA-based drug delivery systems and limitations of nanocarrier delivery system were reviewed. siRNA is a gene silencer that targets highly conserved sequences which codes for protease 3CL (nsp5) and viral helicase (from 16-18 kbp). Conclusion(s): Thus, siRNA-based therapy is considered highly efficacious as it can hit the highly conserved regions of SARS-CoV-2 RNA.Copyright © 2023, Advanced Scientific Research. All rights reserved.
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The field-deployable point-of-care diagnostic test for rapid detection of SARS-COV-2 is needed for implementation of the control measures. In this direction, recently developed CRISPR technology combined with isothermal recombinase polymerase amplification assay is a versatile highly sensitive detection platform for rapid diagnosis of infectious diseases. Here we report the development of RT-RPA-CRISPR based LFA assay for detection of SARS-CoV-2 targeting conserved RdRp and E genes. Various sets of primers and gRNAs were designed targeting conserved regions of the RdRp and E genes of different lineages of SARS-CoV-2 viruses. The isothermal RT-RPA based amplification reactions were standardized using invitro transcribed RNAs of the target regions. The optimum amplification was observed at 42degreeC for 30 min as confirmed by visualization of the amplicons in agarose gel. Subsequently, CRISPRCAS12 reaction was implemented for specific detection of amplicons. Different sets of gRNAs targeting RdRp and E genes were designed and synthesized by in-vitro transcription. The CRISP/CAS12-gRNA complex and single stranded fluorescence probe were added to the RT-RPA amplicons for cleavage of fluorescence probe in positive reaction. Subsequently, the cleaved probes were detected in precoated LFA strips. Upon probe cleavage reaction, the product was mixed with buffer and loaded into LFA strips. In positive reaction, test line showed strong band in test line and light band in control line. The standardized RT-RPA-CRISPR-LFA assay was tested for detection of SARS-CoV-2 using previously isolated RNAs from clinical cases of human SARS-CoV-2 infections. The developed assay successfully detected the positive cases. In conclusion, the developed assay could serve as versatile POC platform for rapid detection of SARS-CoV-2 nucleic acids in human as well as animals.
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Background: The potential aerosol spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV- 2) has been suggested. While indoor air sampling for SARS-CoV- 2 has demonstrated detectable viral RNA and has been related to virus transmission, the contribution of outdoor air to the spread of the viral infection is not yet known. We aimed at developing a methodology to detect the virus in outdoor air. Method(s): T he s ampling w as p erformed u sing a C HEMVOL v olumetric impactor (Butraco) equipped with 2 stages (PM > 10 & 2.5 > PM > 10um). Filters were collected and preserved at -80 degreeC. Total RNA extraction was performed directly from the collected filters with the Phenol-Chloroform method using TRItidy GTM reagent according to the manufacturer's instructions. For total RNA purification samples were purified with the commercial kit E.Z.N.A. Total RNA Kit I. Real-Time Reverse Transcription PCR was executed to detect the N gene from the Sarbecovirus family and RdRp gene from SARS-CoV- 2 using the ViroReal Kit SARS-CoV- 2 Multiplex. A protein-rich fraction was obtained with ammonium bicarbonate buffer extraction followed by lyophilization. SARS-CoV- 2 spike protein was assessed by specific immunological detection (SARS-CoV- 2 Antigen Test Kit). Result(s): RT-PCR for N gene results, identifying Sarbecovirus family, were positive and Cq > 33, in the samples from the last week of December 2020 and the first and second weeks of January 2021, in both PM > 10 and 2.5 > PM > 10. The RdRp gene was undetectable, probably due to low virus concentration. The protein samples from the same days tested positive for the specific antigen spike protein. All results combined confirm the detection of SARS-CoV- 2 in outdoor air. Conclusion(s): Airborne SARS-CoV- 2 was detected in ambient air. These results will contribute to an early detection of SARS-Cov- 2 in ambient air, thus eventually providing the base for early alert systems allowing the implementation of preventive measures to control outbreaks.
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Purpose: Since the coronavirus disease 2019 (COVID-19) pandemic began, new variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have emerged, and distinct epidemic waves of COVID-19 have occurred for an extended period. This study aimed to analyze the clinical and epidemiological characteristics of children with COVID-19 from the third wave to the middle of the fourth epidemic wave in Korea. Method(s): We retrospectively reviewed the medical records of hospitalized patients aged <=18 years with laboratory-confirmed COVID-19. The study periods were divided into the third wave (from November 13, 2020 to July 6, 2021) and the fourth wave (from July 7 to October 31, 2021). Result(s): Ninety-three patients were included in the analysis (33 in the third and 60 in the fourth waves). Compared with the third wave, the median age of patients was significantly older during the fourth wave (6.7 vs. 2.8 years, P=0.014). Household contacts was reported in 60.2% of total patients, similar in both periods (69.7 vs. 55.0%, P=0.190). Eighty-one (87.1%) had symptomatic SARS-CoV-2 infection. Among these, 10 (12.3%) had no respiratory symptoms. Anosmia or ageusia were more commonly observed in the fourth epidemic wave (10.7 vs. 34.0%, P=0.032). Most respiratory illness were upper respiratory tract infections (94.4%, 67/71), 4 had pneumonia. The median cycle threshold values (detection threshold, 40) for RNA-dependent RNA polymerase (RdRp) and envelope (E) genes of SARS-CoV-2 were 21.3 and 19.3, respectively. There was no significant difference in viral load during 2 epidemic waves. Conclusion(s): There were different characteristics during the two epidemic waves of COVID-19.Copyright © 2022 The Korean Society of Pediatric Infectious Diseases.
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Background: The current pandemic outbreak of COVID-19 due to viral infections by SARS-CoV-2 has now become associated with severe commotion on global healthcare and the economy. Objective(s): In this extreme situation, when vaccine or effective new drugs against COVID-19 are still not available, the only quick and feasible therapeutic alternative would be the drug repurpos-ing approach. Method(s): In the present work, in silico screening of some anti-viral and antiprotozoal drugs was performed based on docking using Autodock. Result(s): Two known anti-viral drugs, sorivudine and noricumazole B, are predicted to bind to the active site of the viral proteases, namely cysteine-like protease or 3CL protease (3CLpro) and pa-pain-like protease (PLpro), respectively, with a highly favorable free energy of binding. Further, the promising molecules were subjected for checking their activity on other molecular targets in SARS-CoV-2 like spike protein S1, RNA dependent RNA polymerase (RdRp), and angiotensin converting enzyme 2 (ACE2) receptor. But the compounds were found non-effective on the rest of the molecular targets. Conclusion(s): Sorivudine alone or a combination of sorivudine and noricumazole B may be adminis-tered to impede viral replication, though the predicted drug likeliness of noricumazole B is not much satisfactory. These observations are solely based on the results from blind docking with protein molecules and need to be further corroborated with experimental results.Copyright © 2021 Bentham Science Publishers.
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A century after the outbreak of the Spanish flu, the world is suffering from another pandemic because of the coronavirus. The virus took a toll on more than millions of lives worldwide and continues to affect the health and socio-economic infrastructure all over the world. This study explores the epidemiology, etiology, and transmission of the virus and its phylogenetic relationship with SARS and MERS coronavirus responsible for the 2002 and 2012 viral outbreak. Furthermore, this review highlights the key features of the viral genome and essential viral proteins responsible for the viral life cycle, evading host immune response, and viral immunopathology with therapeutics from "Recovery" and "Solidarity" trials. The review culminates with a discussion on different classes of prominent vaccines and their efficacy. An overall understanding of essential viral proteins and their role in pathogenesis, repurposed drugs, and vaccine development is the rationale of the present review.Copyright © 2021 Bentham Science Publishers.
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Aims: The research work aims to apply the current virtual screening approaches for rapid screening of available compounds as inhibitors of the novel coronavirus (COVID-19). Background(s): The worldwide pandemic, uncontrolled spread, and lack of effective therapeutics demand novel SARS-CoV-2 inhibitory anti-viral agents. Objective(s): The major objectives of the present work are - i) effective utilization of open-source com-puter-aided drug design (CADD) tools;ii) to prepare a database according to chemical structure similarity to the reported anti-viral drug, Favipiravir;and iii) to investigate potential inhibitors of the novel coronavirus. Method(s): The dataset was prepared based on the chemical structure similarity feature of ChemSpider. The virtual screening was carried out using molecular docking and ADMET properties. For performing molecular docking studies, the standard docking protocol of iGEMDOCK was used. Result(s): Based on chemical structure similarity search to Favipiravir, a small library of 40 compounds was designed. The docking score and ADMET properties were analyzed to prioritize the compounds. Conclusion(s): The virtual screening resulted in the identification of potential anti-viral compounds. Among the designed library of compounds based on structural similarity to Favipiravir, 70% of compounds were found to possess docking scores more than that of Favipiravir. The amino acid residues involved in binding at the RNA dependent RNA polymerase (RdRp) were identified. The compounds have shown acceptable ADME properties and are potentially non-toxic. Other: The study has successfully applied the open-source CADD tools to investigate the novel SARS-CoV-2 polymerase inhibitors.Copyright © 2021 Bentham Science Publishers.
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At the beginning of 2020, a pandemic of a novel coronavirus infection was declared in the world. Since the beginning of the pandemic, the search for drugs for etiotropic therapy as the basis for the treatment of the infectious process has begun. The review provides data on the application points of antiviral activity of drugs, taking into account the life cycle of the etiological agent - the SARS-CoV-2 virus. The mechanisms of drug action on RNA-dependent RNA polymerase (molnupiravir, remdesivir, favipiravir) and protease (nirmatrelvir together with ritonavir) SARS-CoV-2 are described. Among of outpatient patients at risk, the use of molnupiravir up to 5 days from the onset of the disease provided a 30% reduction in the risk of hospitalization and an 89% reduction in the risk of death. The use of a 10-day course of remdesivir in inpatient patients led to a reduction in the duration of clinical manifestations by 5 days, and the use of the drug for 3 days on an outpatient basis had a beneficial effect on a group of high-risk patients in the form of a reduction in the risk of hospitalization and death by 87%. Among outpatient patients using favipiravir, the onset of clinical improvement was noted 4 days earlier compared to the control group. The administration of nirmatrelvir in combination with ritonavir on an outpatient basis led to an 89% reduction in the risk of hospitalization or death. The molecular basis and principles of the use of blocking monoclonal antibodies as a fundamentally new group of biological drugs for etiotropic therapy are discussed. Information is provided on the effects of drugs on alpha, beta, gamma, delta and omicron variants of the virus. The profile of drug-drug interaction of drugs and basic therapy is analyzed. Early initiation of etiotropic therapy on an outpatient regime provides a more favorable course of the disease, which is characterized by a shorter duration of clinical manifestations, a reduced risk of hospitalization and the onset of death.Copyright © 2022 Interregional public organization Association of infectious disease specialists of Saint-Petersburg and Leningrad region (IPO AIDSSPbR). All rights reserved.
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The COVID-19 pandemic is raging across the globe, with the total active cases increas-ing each day. Globally over 63 million COVID-19cases and more than 1.4 million deaths have been reported to WHO. Throughout the world, academicians, clinicians and scientists are working tirelessly on developing a treatment to combat this pandemic. The origin of novel SARS-CoV-2 virus still remains foggy but is believed to have originated from a bat coronavirus RaTG13 with which it shares approximately 96% sequence similarity. In the present review, the authors have pro-vided an overview of the COVID-19 pandemic, epidemiology, transmission, developments related to diagnosis, drugs and vaccines, along with the genetic diversity and lifecycle of the SARS-CoV-2 based on the current studies and information available.Copyright © 2022 Bentham Science Publishers.
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Background: This article is aimed to provide an updated landscape of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) genomic mutations emerged since its first identification and sequencing. Method(s): We downloaded and analyzed all mutations within the SARS-CoV-2 RNA genome submitted up to February 8, 2022 to the website of the National Center for Biotechnology Information (NCBI), which contains all variants in Sequence Read Archive (SRA) records compared to the prototype SARS-CoV-2 reference sequence NC_045512.2. Result(s): Our search identified 26,005 different mutations. The largest number of mutations was located within the gene encoding for the Nsp3 protein (20.7%), followed by the gene encoding for the spike protein (14.6%). Overall, 17,948/26,005 (69.0%) of these mutations interested single nucleotide positions, thus spanning over ~62% of the entire SARS-CoV-2 genome. Of all mutations, 61.5% were non-synonymous, whilst 17.4% of those in the gene encoding for the spike protein involved the sequence of the receptor binding domain, 59.2% of which were non-synonymous. When the number of mutations was expressed as ratio to the gene size, the highest ratio was found in the sequence encoding for ORF7a (ratio, 2.25), followed by ORF7b (ratio, 1.85), ORF8 (ratio, 1.60) and ORF3a (ratio, 1.48). The gene encoding for RNA-dependent RNA polymerase accounted for only 0.1% of all mutations, with considerably low ratio with the gene size (i.e., ratio, 0.01). Conclusion(s): The results of our analysis demonstrate that SARS-CoV-2 has enormously mutated since its first sequence has been identified over 2 years ago.Copyright © 2022 AME Publishing Company. All rights reserved.
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Background: A novel coronavirus disease, 2019-nCoV (COVID-19), was reported first in Wuhan, the capital of Hubei, China, in late December 2019 and subsequently reached pandemic level affecting around 213 countries. As of 24th May 2020, the total number of positive cases confirmed is 5,446,514 and 344,754 death reports worldwide. COVID-19 infection causes pneumonia-like severe respiratory infection and acute lung failure. Severe acute respiratory syndrome coron-avirus 2 (SARS-CoV-2) is a positive-sense single-stranded RNA beta coronavirus that is a confirmed causative agent of COVID-19. SARS-CoV-2 may use angiotensin-converting enzyme 2 (ACE2), unlike the receptor utilized by SARS-CoV (emerged in 2002) to infect humans. People with a history of hypertension, chronic obstructive pulmonary disease, diabetes, cardiovascular disease are more susceptible to SARS-CoV-2. Objective(s): The purpose of this review was to help the society to distinguish and deal with SARS-CoV-2, and make available a reference for forthcoming studies. Method(s): Recently, diagnostic primer sets on the SARS-CoV-2 genome have been identified. The receptor-binding domain of SARS-COV-2 highlighted the mode by which beta-CoV recognizes ACE2. Various diagnostic tools are available to differentiate and identify SARS-CoV-2 infection as RT-PCR, antigen detection assay, and antibody detection assay. Different strategies have been employed to control the SARS-CoV-2, considering various drug targets like the main protease (3-CLPro), papain-like protease (PLpro), helicase (NSP13), RNA dependent RNA polymerase (RdR-p), and viral envelope (E) protein. Conclusion(s): In the present review, we have updated details of transmission, pathogenesis, genome structure, diagnostic criteria, clinical characteristics, therapeutics, and vaccine development of the SARS-CoV-2 infection, which may be significant in the control and response to the COVID-19 out-break.Copyright © 2021 Bentham Science Publishers.
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Coronavirus disease (COVID-19) pandemic is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a new coronavirus isolated from Wuhan, China. It is a global health emergency, and there is no effective antiviral therapeutics available to date. Continuous structural genomic insights of SARS-CoV-2 proteins provide a warranty for the development of ra-tional-based antivirals. Nevertheless, a structure-based drug candidate with multiple therapeutic actions would be a practical choice of medication in the treatment of severe COVID-19 patients. Cordycepin from medicinal fungi (Cordyceps spp.) and its nucleoside analogs targeting viral RNA-dependent RNA polymerase and human RNase L have potent antiviral activity against various human viruses with additional immunomodulatory and anti-inflammatory effects. Anti-inflammation treatment is of pivotal importance and should be timely tailored to the individual patient along with antivirals. Our perspective on the combined antiviral and anti-inflammatory effects of cordycepin and its analogs suggests them as new therapeutics in the treatment of systemic COVID-19 infec-tion.Copyright © 2022 Bentham Science Publishers.
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Aim: To evaluate the significance of E gene analysis in addition to N and RdRp genes of SARS-CoV-2, and to compare the specificity and sensitivity of targets. Material(s) and Method(s): We used two reverse transcription-PCR assays: one targeting N, E and RdRp and the other targeting N and RdRp genes and analyzed variation in threshold cycle (Ct) values. Result(s): Of the 155 samples, 70.32% tested positive: all three genes were detected in 45.87%, N and RdRp in 19.27% and only N in 34.86%. Patients negative for the E gene were tested after symptoms disappeared and Ct values were significantly higher. Conclusion(s): Samples negative for the E gene were potentially false positive and clinical conditions should be assessed while interpreting results.Copyright © 2023 Future Medicine Ltd.
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In this paper, we present the first idea of using a DNA triple helix structure to inhibit CRISPR-Cas12a activity and apply it to the design of an electrochemiluminescent biosensor for the detection of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA-dependent RNA polymerase (RdRp) gene in real samples and environmental surveillance. We employed a segment from the RdRp gene of SARS-CoV-2 by an entropy-driven reaction, which was paired with double-stranded DNA that can activate CRISPR-Cas12a activity by Hoogsteen pairing to form triple-stranded DNA, thereby inhibiting the binding interaction of the double-stranded DNA with CRISPR-Cas12a, which in turn inhibits the trans cleavage activity of CRISPR-Cas12a. The inhibited CRISPR-Cas12a is unable to cut the nucleic acid modified on the electrode surface, resulting in the inability of the ferrocene (Fc) modified on the other end of the nucleic acid to move away from the electrode surface, and thus failing to cause electrochemiluminescence changes in GOAu-Ru modified on the electrode surface. The extent of the electrogenic chemiluminescence change can reflect the concentration of the gene to be tested. Using this system, we achieved the detection of the SARS-CoV-2 RdRp gene with a detection limit of 32.80 aM.
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OBJECTIVE To summarize the basic information, mechanism of action, pharmacokinetics, efficacy, safety, interactions, and precautions of azvudine, to provide references for its clinical use. METHODS Literatures related to azvudine from the official website of Chinese clinical trial regi stry, clinicaltrials.gov, Pubmed, CNKI and Wanfang were systematically searched and summarized. RESULTS Azvudine is an oral small-molecule corona virus disease(COVID-19) treatment drug independently developed by China. As a nucleoside analogue targeting to viral RNA-dependent RNA polymerases (RdRp), it can inhibit RNA virus reverse transcription process and replication process. The results of phase III clinical trials showed that azvudine could significantly shorten the time of nucleic acid conversion in patients with mild to moderate corona virus disease (COVID-19). Compared with the control group, the azvudine group can significantly shorten the improvement time of pneumonia. For moderate and severe patients, azvudine treatment also showed significant therapeutic effects in the time of nucleic acid conversion, discharge, and rehabilitation. CONCLUSION The drug possesses good safety and tolerability in patients, which provide a choice for the clinical treatment of COVID-19.Copyright © 2022 Chinese Pharmaceutical Association. All rights reserved.
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Background: SARS-nCOV-2 is a variant of the known SARS coronavirus family. The mutations in viruses are very rapid and can play a crucial role in the evolution or devolution of the organism. This has a direct impact on "host jumping" and the pathogenicity of the virus. Objective(s): The study aims to understand the frequency of genomic variations that have occurred in the virus affecting the Indian sub-population. The impact of variations translating to proteins and its consequences affecting protein stability and interaction were studied. Method(s): Phylogenetic analysis of the 140 genomes from the India region was performed, followed by SNP and Indel analysis of both CDS and non-CDS regions. This effort was followed by a prediction of mutations occurring in 8 proteins of interest and the impact on protein stability and prospective drug interactions. Result(s): Genomes showed variability in origin, and major branches can be mapped to the 2002 outbreak of SARS. The mutation frequency in CDS regions showed that 241 C >T, 3037 C >T, 2836 C >T, and 6312 C >A occurred in 81.5% of genomes mapping to major genes. Corresponding mutations were mapped to protein sequences. The effect of mutations occurring in spike glycoprotein, RNA dependent RNA polymerase, nsp8, nucleocapsid and 3c protease was also depicted. Conclusion(s): Whilst the mutations in spike glycoprotein showcased an increase in protein stability, the residues undergoing mutations were also a part of drug binding pockets for hydroxychloro-quine. Mutations occurring in other proteins of interest led to a decrease in protein stability. The mutations were also a part of drug binding pockets for Favipiravir, Remdesivir and Dexametha-sone. The work allows analyzing larger datasets to understand mutation patterns globally.Copyright © 2021 Bentham Science Publishers.
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Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has infected around 13 million people and has caused more than 5.7 lakh deaths worldwide since December 2019. In the absence of FDA approved drugs for its treatment, only symptomatic management is done. Method(s): We attempted to uncover potential therapeutic targets of spike, helicase, and RNA dependent RNA polymerase (RdRp) proteins of the SARS-CoV-2 employing a computational approach. The PDB structure of spike and RdRp and predicted structure of helicase proteins were docked with 100 approved anti-viral drugs, natural compounds, and some other chemical compounds. Result(s): The anti-SARS ligands EK1 and CID 23631927, and NCGC00029283 are potential entry in-hibitors as they showed affinity with immunogenic Receptor Binding Domain (RBD) of the spike pro-tein. This RBD interacts with Angiotensin Converting Enzyme (ACE2) receptor, facilitating the entry of virion in the host cells. The FDA approved drugs, including Nelfinavir, Saquinavir, Tipranavir, Setrobu-vir, Indinavir, and Atazanavir, showed potential inhibitory activity against targeted domains and thus, may act as entry or replication inhibitor or both. Furthermore, several anti-HCoV natural compounds, including Amentoflavone, Rutin, and Tannin, are also potential entry and replication inhibitors as they showed affinity with RBD, P-loop containing nucleoside triphosphate hydrolase, and the catalytic domain of the respective protein. Dithymoquinone showed significant inhibitory potential against the fusion peptide of S2 domain. Importantly, Tannin, Dithymoquinone, and Rutin can be extracted from Nig-ella sativa seeds and thus, may prove to be one of the most potential anti-SARS-CoV-2 inhibitors. Conclusion(s): Several potential ligands were identified with already known anti-HCoVs activities. Fur-thermore, as this study showed that some of the ligands acted as both entry and replication inhibitors against SARS-CoV-2, it is envisaged that a combination of either inhibitor with a dual mode of action would prove to be a much desired therapeutic option against this viral infection.Copyright © 2021 Bentham Science Publishers.
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SARS-CoV-2, a novel coronavirus, has caused the pneumonia outbreak in the entire world and every day, the number of cases is increasing in an exponential manner. Unfortunately, there is no clinically approved drug or vaccine specific for SARS-CoV-2 to date, and analysis of the current rate of spread of infection suggests that there is no time to wait for the approval of drugs and vaccine production. The sequence and phylogenetic analysis of SARS-CoV-2 has shown that it is very much similar to SARS/SARS-like coronaviruses and belongs to the betacoronavirus genera and bats are likely to be the native host of the SARS-CoV-2. Interestingly, the SARS-CoV-2 S protein and SARS-CoV S protein shared an almost identical 3-D structure in the RBD domain and the SARS-CoV-2 S protein was found to have a significant binding affinity to human ACE2. Further, RdRp and 3CLpro protease of SARS-CoV-2 share over 95% of sequence similarity with those of SARS-CoV. Recently, various molecular docking studies have been carried out to search for natural compounds that can target S protein, RdRp, 3CLpro, and nsp proteins of SARS-CoV-2. This review is an attempt to give a comprehensive idea of the different natural products that can be used to target SARS-CoV-2. However, further research is necessary to investigate the potential uses of these predicted SARS-CoV-2 inhibitors in combating the COVID-19 pandemic.Copyright © 2021 Bentham Science Publishers.
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OBJECTIVE To summarize the basic information, mechanism of action, pharmacokinetics, efficacy, safety, interactions, and precautions of azvudine, to provide references for its clinical use. METHODS Literatures related to azvudine from the official website of Chinese clinical trial regi stry, clinicaltrials.gov, Pubmed, CNKI and Wanfang were systematically searched and summarized. RESULTS Azvudine is an oral small-molecule corona virus disease(COVID-19) treatment drug independently developed by China. As a nucleoside analogue targeting to viral RNA-dependent RNA polymerases (RdRp), it can inhibit RNA virus reverse transcription process and replication process. The results of phase III clinical trials showed that azvudine could significantly shorten the time of nucleic acid conversion in patients with mild to moderate corona virus disease (COVID-19). Compared with the control group, the azvudine group can significantly shorten the improvement time of pneumonia. For moderate and severe patients, azvudine treatment also showed significant therapeutic effects in the time of nucleic acid conversion, discharge, and rehabilitation. CONCLUSION The drug possesses good safety and tolerability in patients, which provide a choice for the clinical treatment of COVID-19.