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1.
J Nat Med ; 76(2): 402-409, 2022 Mar.
Article in English | MEDLINE | ID: covidwho-1616220

ABSTRACT

The emergence of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic in 2019 has led to a global health crisis. Mutations of the SARS-CoV-2 genome have impeded the development of effective therapeutics and vaccines against SARS-CoV-2. Natural products are important for discovering therapeutics to treat the 2019 coronavirus disease (COVID-19). In the present study, we investigated the antiviral activity of herbal drug extracts from Polygala Root, Areca, and Quercus Bark and natural compounds derived from herbal drug such as baicalin and glabridin, with IC50 values of 9.5 µg/ml, 1.2 µg/ml, 5.4 µg/ml, 8.8 µM, and 2.5 µM, respectively, against SARS CoV-2 infection in vitro. Certain herbal drug extracts and natural compounds were found to inhibit viral RNA levels and infectious titers of SARS-CoV-2 in a dose-dependent manner. Furthermore, viral protein analyses showed that herbal drug extracts and natural compounds effectively inhibited SARS-CoV-2 in the various entry treatments. Our study revealed that three herbal drugs are good candidates for further in vivo and clinical studies.


Subject(s)
COVID-19 , Pharmaceutical Preparations , Antiviral Agents/pharmacology , Antiviral Agents/therapeutic use , COVID-19 Vaccines , Humans , SARS-CoV-2
2.
Trop Med Health ; 50(1): 6, 2022 Jan 07.
Article in English | MEDLINE | ID: covidwho-1613261

ABSTRACT

BACKGROUND: Genetic variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) began to emerge in 2020 and have been spreading globally during the coronavirus disease 2019 (COVID-19) pandemic. Despite the presence of different COVID-19 vaccines, the discovery of effective antiviral therapeutics for the treatment of patients infected with SARS-CoV-2 are still urgently needed. A natural amino acid, 5-aminolevulinic acid (5-ALA), has exhibited both antiviral and anti-inflammatory activities. In a previous study, we demonstrated an in vitro antiviral effect of 5-ALA against SARS-CoV-2 infection without significant cytotoxicity. In the present study, we sought to investigate whether 5-ALA with or without sodium ferrous citrate (SFC) can inhibit in vitro both the original SARS-CoV-2 Wuhan strain and its variants, including the Alpha, Beta, Gamma and Delta strains. METHODS: The antiviral activity of ALA with or without SFC was determined in Vero-E6 cell. The virus inhibition was quantified by real time RT-PCR. RESULTS: Co-administration of 5-ALA and SFC inhibited the Wuhan, Alpha and Delta variants of SARS-CoV-2 with IC50 values of 235, 173 and 397 µM, respectively, and the Beta and Gamma variants with IC50 values of 1311 and 1516 µM. CONCLUSION: Our study suggests that 5-ALA with SFC warrants accelerated clinical evaluation as an antiviral drug candidate for treating patients infected with SARS-CoV-2 variants.

3.
Int J Environ Res Public Health ; 18(18)2021 09 13.
Article in English | MEDLINE | ID: covidwho-1409577

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of coronavirus disease 2019 (COVID-19). Real-time RT-PCR is the most commonly used method for COVID-19 diagnosis. However, serological assays are urgently needed as complementary tools to RT-PCR. Hachim et al. 2020 and Burbelo et al. 2020 demonstrated that anti-nucleocapsid(N) SARS-CoV-2 antibodies are higher and appear earlier than the spike antibodies. Additionally, cross-reactive antibodies against N protein are more prevalent than those against spike protein. We developed a less cross-reactive immunoglobulin G (IgG) indirect ELISA by using a truncated recombinant SARS-CoV-2 N protein as assay antigen. A highly conserved region of coronaviruses N protein was deleted and the protein was prepared using an E. coli protein expression system. A total of 177 samples collected from COVID-19 suspected cases and 155 negative control sera collected during the pre-COVID-19 period were applied to evaluate the assay's performance, with the plaque reduction neutralization test and the commercial SARS-CoV-2 spike protein IgG ELISA as gold standards. The SARS-CoV-2 N truncated protein-based ELISA showed similar sensitivity (91.1% vs. 91.9%) and specificity (93.8% vs. 93.8%) between the PRNT and spike IgG ELISA, as well as also higher specificity compared to the full-length N protein (93.8% vs. 89.9%). Our ELISA can be used for the diagnosis and surveillance of COVID-19.


Subject(s)
COVID-19 , Nucleocapsid Proteins , Antibodies, Viral , COVID-19 Testing , Enzyme-Linked Immunosorbent Assay , Escherichia coli , Humans , Immunoglobulin G , Nucleocapsid Proteins/genetics , SARS-CoV-2 , Sensitivity and Specificity , Spike Glycoprotein, Coronavirus
4.
J Infect Chemother ; 27(10): 1525-1528, 2021 Oct.
Article in English | MEDLINE | ID: covidwho-1313247

ABSTRACT

Polymerase chain reaction (PCR) testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is necessary for confirming a diagnosis of Coronavirus disease 2019 (COVID-19). Here we present a COVID-19 case of an elderly woman whose SARS-CoV-2 PCR tests showed false negative repeatedly by evaluating with different sampling sites and procedures. Nasopharyngeal swabs, suctioned sputum, and tongue swabs were collected for SARS-CoV-2-PCR. As for tongue swabs, we compared between two different sample conditions; one obtained with dry condition and the other obtained with moistened condition inside the oral cavity. SARS-CoV-2-PCR showed positive for an extended period with suctioned sputum samples compared with nasopharyngeal swabs and tongue swabs. No SARS-CoV-2 from a nasopharyngeal swab sample obtained on day 46 after symptoms onset was isolated despite high viral load (183740.5 copies/5µL). An adequate production of neutralizing antibody in a serum sample on day 46 was also confirmed. The number of RNA copies of the tongue swab samples was higher with moistened condition than with dry condition. The present case suggests that the difference of sampling site or sample condition can affect PCR results. High loads viral RNA detection does not always correlate with infectivity.


Subject(s)
COVID-19 , SARS-CoV-2 , Aged , Female , Humans , Nasopharynx , Polymerase Chain Reaction , RNA, Viral , Specimen Handling
5.
Viruses ; 13(7)2021 06 24.
Article in English | MEDLINE | ID: covidwho-1289017

ABSTRACT

Arenaviruses and coronaviruses include several human pathogenic viruses, such as Lassa virus, Lymphocytic choriomeningitis virus (LCMV), SARS-CoV, MERS-CoV, and SARS-CoV-2. Although these viruses belong to different virus families, they possess a common motif, the DED/EDh motif, known as an exonuclease (ExoN) motif. In this study, proof-of-concept studies, in which the DED/EDh motif in these viral proteins, NP for arenaviruses, and nsp14 for coronaviruses, could be a drug target, were performed. Docking simulation studies between two structurally different chemical compounds, ATA and PV6R, and the DED/EDh motifs in these viral proteins indicated that these compounds target DED/EDh motifs. The concentration which exhibited modest cell toxicity was used with these compounds to treat LCMV and SARS-CoV-2 infections in two different cell lines, A549 and Vero 76 cells. Both ATA and PV6R inhibited the post-entry step of LCMV and SARS-CoV-2 infection. These studies strongly suggest that DED/EDh motifs in these viral proteins could be a drug target to combat two distinct viral families, arenaviruses and coronaviruses.


Subject(s)
Antiviral Agents/pharmacology , Exoribonucleases/antagonists & inhibitors , Lymphocytic choriomeningitis virus/drug effects , SARS-CoV-2/drug effects , Viral Nonstructural Proteins/antagonists & inhibitors , Viral Proteins/antagonists & inhibitors , Virus Replication/drug effects , A549 Cells , Amino Acid Motifs , Animals , Chlorocebus aethiops , Drug Discovery , Humans , Molecular Docking Simulation , Vero Cells
6.
Viruses ; 13(6)2021 06 16.
Article in English | MEDLINE | ID: covidwho-1286940

ABSTRACT

Dengue fever, caused by the mosquito-borne dengue virus (DENV), has been endemic in Myanmar since 1970 and it has become a significant public health burden. It is crucial that circulating DENV strains are identified and monitored, and that their transmission efficiency and association with disease severity is understood. In this study, we analyzed DENV-1, DENV-2, DENV-3, and DENV-4 serotypes in 1235 serum samples collected in Myanmar between 2017 and 2019. Whole-genome sequencing of DENV-1-4 demonstrated that most DENV-1-4 strains had been circulating in Myanmar for several years. We also identified the emergence of DENV-3 genotype-I in 2017 samples, which persisted through 2018 and 2019. The emergence of the strain coincided with a period of increased DENV-3 cases and marked changes in the serotype dynamics. Nevertheless, we detected no significant differences between serum viral loads, disease severity, and infection status of individuals infected with different DENV serotypes during the 3-year study. Our results not only identify the spread of a new DENV-3 genotype into Yangon, Myanmar, but also support the importance of DENV evolution in changing the epidemic dynamics in endemic regions.


Subject(s)
Communicable Diseases, Emerging/epidemiology , Communicable Diseases, Emerging/virology , Dengue Virus/classification , Dengue Virus/genetics , Dengue/epidemiology , Dengue/virology , Genotype , Adolescent , Amino Acid Substitution , Child , Child, Preschool , Dengue/diagnosis , Dengue/history , Dengue Virus/isolation & purification , Disease Outbreaks , Genetic Variation , Genome, Viral , History, 21st Century , Humans , Myanmar , Phylogeny , Seroepidemiologic Studies , Serogroup , Whole Genome Sequencing
8.
Biochem Biophys Res Commun ; 545: 203-207, 2021 03 19.
Article in English | MEDLINE | ID: covidwho-1068871

ABSTRACT

The current COVID-19 pandemic requires urgent development of effective therapeutics. 5-amino levulinic acid (5-ALA) is a naturally synthesized amino acid and has been used for multiple purposes including as an anticancer therapy and as a dietary supplement due to its high bioavailability. In this study, we demonstrated that 5-ALA treatment potently inhibited infection of SARS-CoV-2, a causative agent of COVID-19, in cell culture. The antiviral effects could be detected in both human and non-human cells, without significant cytotoxicity. Therefore, 5-ALA is worth to be further investigated as an antiviral drug candidate for COVID-19.


Subject(s)
Antiviral Agents/pharmacology , COVID-19/drug therapy , Levulinic Acids/pharmacology , Animals , Antiviral Agents/administration & dosage , COVID-19/prevention & control , COVID-19/virology , Caco-2 Cells , Chlorocebus aethiops , Citric Acid , Dose-Response Relationship, Drug , Drug Evaluation, Preclinical/methods , Ferrous Compounds/pharmacology , Humans , Levulinic Acids/administration & dosage , Vero Cells
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