Displaying publications 41 - 55 of 55 in total

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  1. Fulltext Cordycepin Inhibits Virus Replication in Dengue Virus-Infected Vero Cells
    Panya A, Songprakhon P, Panwong S, Jantakee K, Kaewkod T, Tragoolpua Y, et al.
    Molecules, 2021 May 23;26(11).
    PMID: 34071102 DOI: 10.3390/molecules26113118
    Dengue virus (DENV) infection causes mild to severe illness in humans that can lead to fatality in severe cases. Currently, no specific drug is available for the treatment of DENV infection. Thus, the development of an anti-DENV drug is urgently required. Cordycepin (3'-deoxyadenosine), which is a major bioactive compound in Cordyceps (ascomycete) fungus that has been used for centuries in Chinese traditional medicine, was reported to exhibit antiviral activity. However, the anti-DENV activity of cordycepin is unknown. We hypothesized that cordycepin exerts anti-DENV activity and that, as an adenosine derivative, it inhibits DENV replication. To test this hypothesis, we investigated the anti-DENV activity of cordycepin in DENV-infected Vero cells. Cordycepin treatment significantly decreased DENV protein at a half-maximal effective concentration (EC50) of 26.94 μM. Moreover, DENV RNA was dramatically decreased in cordycepin-treated Vero cells, indicating its effectiveness in inhibiting viral RNA replication. Via in silico molecular docking, the binding of cordycepin to DENV non-structural protein 5 (NS5), which is an important enzyme for RNA synthesis, at both the methyltransferase (MTase) and RNA-dependent RNA polymerase (RdRp) domains, was predicted. The results of this study demonstrate that cordycepin is able to inhibit DENV replication, which portends its potential as an anti-dengue therapy.
    Matched MeSH terms: Virus Replication/drug effects*
  2. Fulltext A Brief Overview of Potential Treatments for Viral Diseases Using Natural Plant Compounds: The Case of SARS-Cov
    Abiri R, Abdul-Hamid H, Sytar O, Abiri R, Bezerra de Almeida E, Sharma SK, et al.
    Molecules, 2021 Jun 24;26(13).
    PMID: 34202844 DOI: 10.3390/molecules26133868
    The COVID-19 pandemic, as well as the more general global increase in viral diseases, has led researchers to look to the plant kingdom as a potential source for antiviral compounds. Since ancient times, herbal medicines have been extensively applied in the treatment and prevention of various infectious diseases in different traditional systems. The purpose of this review is to highlight the potential antiviral activity of plant compounds as effective and reliable agents against viral infections, especially by viruses from the coronavirus group. Various antiviral mechanisms shown by crude plant extracts and plant-derived bioactive compounds are discussed. The understanding of the action mechanisms of complex plant extract and isolated plant-derived compounds will help pave the way towards the combat of this life-threatening disease. Further, molecular docking studies, in silico analyses of extracted compounds, and future prospects are included. The in vitro production of antiviral chemical compounds from plants using molecular pharming is also considered. Notably, hairy root cultures represent a promising and sustainable way to obtain a range of biologically active compounds that may be applied in the development of novel antiviral agents.
    Matched MeSH terms: Virus Replication/drug effects
  3. Antiviral activity of selected flavonoids against Chikungunya virus
    Lani R, Hassandarvish P, Shu MH, Phoon WH, Chu JJ, Higgs S, et al.
    Antiviral Res, 2016 Sep;133:50-61.
    PMID: 27460167 DOI: 10.1016/j.antiviral.2016.07.009
    This study focuses on the antiviral activity of selected flavonoids against the Chikungunya virus (CHIKV), a mosquito-transmitted virus that can cause incapacitating arthritis in infected individuals. Based on the results of screening on Vero cells, the tested compounds were evaluated further with various assays, including cytotoxicity assay, virus yield assay by quantitative reverse transcription polymerase chain reaction (qRT-PCR), virus RNA replication assay with a CHIKV replicon cell line, Western blotting, and quantitative immunofluorescence assay. Baicalein, fisetin, and quercetagetin displayed potent inhibition of CHIKV infection, with 50% inhibitory concentrations [IC50] of 1.891 μg/ml (6.997 μM), 8.444 μg/ml (29.5 μM), and 13.85 μg/ml (43.52 μM), respectively, and with minimal cytotoxicity. The time-of-addition studies and various antiviral assays demonstrated that baicalein and quercetagetin mainly inhibited CHIKV binding to the Vero cells and displayed potent activity against extracellular CHIKV particles. The qRT-PCR, immunofluorescence assay, and Western blot analyses indicated that each of these flavonoids affects CHIKV RNA production and viral protein expression. These data provide the first evidence of the intracellular anti-CHIKV activity of baicalein, fisetin, and quercetagetin.
    Matched MeSH terms: Virus Replication/drug effects
  4. Fulltext Antiviral activity of silymarin and baicalein against dengue virus
    Low ZX, OuYong BM, Hassandarvish P, Poh CL, Ramanathan B
    Sci Rep, 2021 10 27;11(1):21221.
    PMID: 34707245 DOI: 10.1038/s41598-021-98949-y
    Dengue is an arthropod-borne viral disease that has become endemic and a global threat in many countries with no effective antiviral drug available currently. This study showed that flavonoids: silymarin and baicalein could inhibit the dengue virus in vitro and were well tolerated in Vero cells with a half-maximum cytotoxic concentration (CC50) of 749.70 µg/mL and 271.03 µg/mL, respectively. Silymarin and baicalein exerted virucidal effects against DENV-3, with a selective index (SI) of 10.87 and 21.34, respectively. Baicalein showed a better inhibition of intracellular DENV-3 progeny with a SI of 7.82 compared to silymarin. Baicalein effectively blocked DENV-3 attachment (95.59%) to the Vero cells, while silymarin prevented the viral entry (72.46%) into the cells, thus reducing viral infectivity. Both flavonoids showed promising antiviral activity against all four dengue serotypes. The in silico molecular docking showed that silymarin could bind to the viral envelope (E) protein with a binding affinity of - 8.5 kcal/mol and form hydrogen bonds with the amino acids GLN120, TRP229, ASN89, and THR223 of the E protein. Overall, this study showed that silymarin and baicalein exhibited potential anti-DENV activity and could serve as promising antiviral agents for further development against dengue infection.
    Matched MeSH terms: Virus Replication/drug effects
  5. Fulltext Identification of 5-Methoxy-2-(Diformylmethylidene)-3,3-Dimethylindole as an Anti-Influenza A Virus Agent
    Tan MC, Wong WY, Ng WL, Yeo KS, Mohidin TB, Lim YY, et al.
    PLoS One, 2017;12(1):e0170352.
    PMID: 28114392 DOI: 10.1371/journal.pone.0170352
    Influenza virus is estimated to cause 3-5 million severe complications and about 250-500 thousand deaths per year. Different kinds of anti-influenza virus drugs have been developed. However, the emergence of drug resistant strains has presented a big challenge for efficient antiviral therapy. Indole derivatives have been shown to exhibit both antiviral and anti-inflammatory activities. In this study, we adopted a cell-based system to screen for potential anti-IAV agents. Four indole derivatives (named 525A, 526A, 527A and 528A) were subjected to the antiviral screening, of which 526A was selected for further investigation. We reported that pre-treating cells with 526A protects cells from IAV infection. Furthermore, 526A inhibits IAV replication by inhibiting the expression of IAV genes. Interestingly, 526A suppresses the activation of IRF3 and STAT1 in host cells and thus represses the production of type I interferon response and cytokines in IAV-infected cells. Importantly, 526A also partially blocks the activation of RIG-I pathway. Taken together, these results suggest that 526A may be a potential anti-influenza A virus agent.
    Matched MeSH terms: Virus Replication/drug effects
  6. A novel peptide inhibits the influenza virus replication by preventing the viral attachment to the host cells
    Rajik M, Omar AR, Ideris A, Hassan SS, Yusoff K
    Int J Biol Sci, 2009 Aug 08;5(6):543-8.
    PMID: 19680476
    Avian influenza viruses (AIV), the causative agent of avian flu or bird flu, cause widespread morbidity and mortality in poultry. The symptoms of the disease range from mild flu like symptoms to death. These viruses possess two important surface glycoproteins, namely hemagglutinin (HA) and neuraminidase (NA) against which neutralizing antibodies are produced. Due to the highly mutative nature of the genes which encode these proteins, the viruses often confer resistance to the current anti-viral drugs making the prevention and treatment of infection challenging. In our laboratory, we have recently identified a novel anti-viral peptide (P1) against the AIV H9N2 from a phage displayed peptide library. This peptide inhibits the replication of the virus in ovo and in vitro by its binding to the HA glycoprotein. In the current study, we demonstrate that the peptide inhibits the virus replication by preventing the attachment to the host cell but it does not have any effect on the viral fusion. The reduction in the viral nucleoprotein (NP) expression inside the host cell has also been observed during the peptide (P1) treatment. This novel peptide may have the potential to be developed as a therapeutic agent for the treatment and control of avian influenza virus H9N2 infections.
    Matched MeSH terms: Virus Replication/drug effects*
  7. Fulltext Baicalin, a metabolite of baicalein with antiviral activity against dengue virus
    Moghaddam E, Teoh BT, Sam SS, Lani R, Hassandarvish P, Chik Z, et al.
    Sci Rep, 2014 Jun 26;4:5452.
    PMID: 24965553 DOI: 10.1038/srep05452
    Baicalin, a flavonoid derived from Scutellaria baicalensis, is the main metabolite of baicalein released following administration in different animal models and human. We previously reported the antiviral activity of baicalein against dengue virus (DENV). Here, we examined the anti-DENV properties of baicalin in vitro, and described the inhibitory potentials of baicalin at different steps of DENV-2 (NGC strain) replication. Our in vitro antiviral experiments showed that baicalin inhibited virus replication at IC50 = 13.5 ± 0.08 μg/ml with SI = 21.5 following virus internalization by Vero cells. Baicalin exhibited virucidal activity against DENV-2 extracellular particles at IC50 = 8.74 ± 0.08 μg/ml and showed anti-adsorption effect with IC50 = 18.07 ± 0.2 μg/ml. Our findings showed that baicalin as the main metabolite of baicalein exerting in vitro anti-DENV activity. Further investigations on baicalein and baicalin to deduce its antiviral therapeutic effects are warranted.
    Matched MeSH terms: Virus Replication/drug effects
  8. Fulltext Protegrin-1 inhibits dengue NS2B-NS3 serine protease and viral replication in MK2 cells
    Rothan HA, Abdulrahman AY, Sasikumer PG, Othman S, Rahman NA, Yusof R
    J Biomed Biotechnol, 2012;2012:251482.
    PMID: 23093838 DOI: 10.1155/2012/251482
    Dengue diseases have an economic as well as social burden worldwide. In this study, the antiviral activity of protegrin-1 (PG-1, RGGRLCYCRRRFCVCVGR) peptide towards dengue NS2B-NS3pro and viral replication in Rhesus monkey kidney (MK2) cells was investigated. The peptide PG-1 was synthesized by solid-phase peptide synthesis, and disulphide bonds formation followed by peptide purification was confirmed by LC-MS and RPHPLC. Dengue NS2B-NS3pro was produced as a single-chain recombinant protein in E. coli. The NS2B-NS3pro assay was carried out by measuring the florescence emission of catalyzed substrate. Real-time PCR was used to evaluate the inhibition potential of PG-1 towards dengue serotype-2 (DENV-2) replication in MK2 cells. The results showed that PG-1 inhibited dengue NS2B-NS3pro at IC(50) of 11.7 μM. The graded concentrations of PG-1 at nontoxic range were able to reduce viral replication significantly (P < 0.001) at 24, 48, and 72 hrs after viral infection. However, the percentage of inhibition was significantly (P < 0.01) higher at 24 hrs compared to 48 and 72 hrs. These data show promising therapeutic potential of PG-1 against dengue infection, hence it warrants further analysis and improvement of the peptide features as a prospective starting point for consideration in designing attractive dengue virus inhibitors.
    Matched MeSH terms: Virus Replication/drug effects*
  9. Fulltext Extract of Scutellaria baicalensis inhibits dengue virus replication
    Zandi K, Lim TH, Rahim NA, Shu MH, Teoh BT, Sam SS, et al.
    BMC Complement Altern Med, 2013 Apr 29;13:91.
    PMID: 23627436 DOI: 10.1186/1472-6882-13-91
    BACKGROUND: Scutellaria baicalensis (S. baicalensis) is one of the traditional Chinese medicinal herbs that have been shown to possess many health benefits. In the present study, we evaluated the in vitro antiviral activity of aqueous extract of the roots of S. baicalensis against all the four dengue virus (DENV) serotypes.

    METHODS: Aqueous extract of S. baicalensis was prepared by microwave energy steam evaporation method (MEGHE™), and the anti-dengue virus replication activity was evaluated using the foci forming unit reduction assay (FFURA) in Vero cells. Quantitative real-time polymerase chain reaction (qRT-PCR) assay was used to determine the actual dengue virus RNA copy number. The presence of baicalein, a flavonoid known to inhibit dengue virus replication was determined by mass spectrometry.

    RESULTS: The IC(50) values for the S. baicalensis extract on Vero cells following DENV adsorption ranged from 86.59 to 95.19 μg/mL for the different DENV serotypes. The IC(50) values decreased to 56.02 to 77.41 μg/mL when cells were treated with the extract at the time of virus adsorption for the different DENV serotypes. The extract showed potent direct virucidal activity against extracellular infectious virus particles with IC(50) that ranged from 74.33 to 95.83 μg/mL for all DENV serotypes. Weak prophylactic effects with IC(50) values that ranged from 269.9 to 369.8 μg/mL were noticed when the cells were pre-treated 2 hours prior to virus inoculation. The concentration of baicalein in the S. baicalensis extract was ~1% (1.03 μg/gm dried extract).

    CONCLUSIONS: Our study demonstrates the in vitro anti-dengue virus replication property of S. baicalensis against all the four DENV serotypes investigated. The extract reduced DENV infectivity and replication in Vero cells. The extract was rich in baicalein, and could be considered for potential development of anti-DENV therapeutics.

    Matched MeSH terms: Virus Replication/drug effects*
  10. Inhibitory effect of doxycycline against dengue virus replication in vitro
    Rothan HA, Mohamed Z, Paydar M, Rahman NA, Yusof R
    Arch Virol, 2014 Apr;159(4):711-8.
    PMID: 24142271 DOI: 10.1007/s00705-013-1880-7
    Doxycycline is an antibiotic derived from tetracycline that possesses antimicrobial and anti-inflammatory activities. Antiviral activity of doxycycline against dengue virus has been reported previously; however, its anti-dengue properties need further investigation. This study was conducted to determine the potential activity of doxycycline against dengue virus replication in vitro. Doxycycline inhibited the dengue virus serine protease (DENV2 NS2B-NS3pro) with an IC50 value of 52.3 ± 6.2 μM at 37 °C (normal human temperature) and 26.7 ± 5.3 μM at 40 °C (high fever temperature). The antiviral activity of doxycycline was first tested at different concentrations against DENV2 using a plaque-formation assay. The virus titter decreased significantly after applying doxycycline at levels lower than its 50 % cytotoxic concentration (CC50, 100 μM), showing concentration-dependent inhibition with a 50 % effective concentration (EC50) of approximately 50 μM. Doxycycline significantly inhibited viral entry and post-infection replication of the four dengue serotypes, with serotype-specific inhibition (high activity against DENV2 and DENV4 compared to DENV1 and DENV3). Collectively, these findings underline the need for further experimental and clinical studies on doxycycline, utilizing its anti-dengue and anti-inflammatory activities to attenuate the clinical symptoms of dengue virus infection.
    Matched MeSH terms: Virus Replication/drug effects*
  11. Fulltext Flavone enhances dengue virus type-2 (NGC strain) infectivity and replication in vero cells
    Zandi K, Lani R, Wong PF, Teoh BT, Sam SS, Johari J, et al.
    Molecules, 2012;17(3):2437-45.
    PMID: 22374315 DOI: 10.3390/molecules17032437
    This study investigates the effects of 2-phenyl-1-benzopyran-4-one (flavone) on DENV-2 infectivity in Vero cells. Virus adsorption and attachment and intracellular virus replication were investigated using a foci forming unit assay (FFUA) and quantitative RT-PCR, respectively. Addition of flavone (100 μg/mL) significantly increased the number of DENV-2 foci by 35.66% ± 1.52 and 49.66% ± 2.51 when added during and after virus adsorption to the Vero cells, respectively. The average foci size after 4 days of infection increased by 33% ± 2.11 and 89% ± 2.13. The DENV-2 specific RNA copy number in the flavone-treated infected cells increased by 6.41- and 23.1-fold when compared to the mock-treated infected cells. Flavone (100 μg/mL) did not promote or inhibit Vero cell proliferation. The CC₅₀ value of flavone against Vero cells was 446 µg/mL. These results suggest that flavone might enhance dengue virus replication by acting antagonistically towards flavonoids known to inhibit dengue virus replication.
    Matched MeSH terms: Virus Replication/drug effects*
  12. Fulltext Inhibition of dengue NS2B-NS3 protease and viral replication in Vero cells by recombinant retrocyclin-1
    Rothan HA, Han HC, Ramasamy TS, Othman S, Rahman NA, Yusof R
    BMC Infect Dis, 2012;12:314.
    PMID: 23171075 DOI: 10.1186/1471-2334-12-314
    Global resurgence of dengue virus infections in many of the tropical and subtropical countries is a major concern. Therefore, there is an urgent need for the development of successful drugs that are both economical and offer a long-lasting protection. The viral NS2B-NS3 serine protease (NS2B-NS3pro) is a promising target for the development of drug-like inhibitors, which are not available at the moment. In this study, we report retrocyclin-1 (RC-1) production in E. coli as a recombinant peptide to test against dengue NS2B-NS3pro.
    Matched MeSH terms: Virus Replication/drug effects*
  13. A Real-Time Cell Analyzing Assay for Identification of Novel Antiviral Compounds against Chikungunya Virus
    Zandi K
    Methods Mol Biol, 2016;1426:255-62.
    PMID: 27233278 DOI: 10.1007/978-1-4939-3618-2_23
    Screening of viral inhibitors through induction of cytopathic effects (CPE) by conventional method has been applied for various viruses including Chikungunya virus (CHIKV), a significant arbovirus. However, it does not provide the information about cytopathic effect from the beginning and throughout the course of virus replication. Conventionally, most of the approaches are constructed on laborious end-point assays which are not capable for detecting minute and rapid changes in cellular morphology. Therefore, we developed a label-free and dynamical method for monitoring the cellular features that comprises cell attachment, proliferation, and viral cytopathogenicity, known as the xCELLigence real-time cell analysis (RTCA). In this chapter, we provide a RTCA protocol for quantitative analysis of CHIKV replication using an infected Vero cell line treated with ribavirin as an in vitro model.
    Matched MeSH terms: Virus Replication/drug effects
  14. Fulltext Characterization of β-d-N4-Hydroxycytidine as a Novel Inhibitor of Chikungunya Virus
    Ehteshami M, Tao S, Zandi K, Hsiao HM, Jiang Y, Hammond E, et al.
    Antimicrob Agents Chemother, 2017 04;61(4).
    PMID: 28137799 DOI: 10.1128/AAC.02395-16
    Chikungunya virus (CHIKV) represents a reemerging global threat to human health. Recent outbreaks across Asia, Europe, Africa, and the Caribbean have prompted renewed scientific interest in this mosquito-borne alphavirus. There are currently no vaccines against CHIKV, and treatment has been limited to nonspecific antiviral agents, with suboptimal outcomes. Herein, we have identified β-d-N4-hydroxycytidine (NHC) as a novel inhibitor of CHIKV. NHC behaves as a pyrimidine ribonucleoside and selectively inhibits CHIKV replication in cell culture.
    Matched MeSH terms: Virus Replication/drug effects
  15. Fulltext Repositioning Ivermectin for Covid-19 treatment: Molecular mechanisms of action against SARS-CoV-2 replication
    Low ZY, Yip AJW, Lal SK
    Biochim Biophys Acta Mol Basis Dis, 2022 Feb 01;1868(2):166294.
    PMID: 34687900 DOI: 10.1016/j.bbadis.2021.166294
    Ivermectin (IVM) is an FDA approved macrocyclic lactone compound traditionally used to treat parasitic infestations and has shown to have antiviral potential from previous in-vitro studies. Currently, IVM is commercially available as a veterinary drug but have also been applied in humans to treat onchocerciasis (river blindness - a parasitic worm infection) and strongyloidiasis (a roundworm/nematode infection). In light of the recent pandemic, the repurposing of IVM to combat SARS-CoV-2 has acquired significant attention. Recently, IVM has been proven effective in numerous in-silico and molecular biology experiments against the infection in mammalian cells and human cohort studies. One promising study had reported a marked reduction of 93% of released virion and 99.98% unreleased virion levels upon administration of IVM to Vero-hSLAM cells. IVM's mode of action centres around the inhibition of the cytoplasmic-nuclear shuttling of viral proteins by disrupting the Importin heterodimer complex (IMPα/β1) and downregulating STAT3, thereby effectively reducing the cytokine storm. Furthermore, the ability of IVM to block the active sites of viral 3CLpro and S protein, disrupts important machinery such as viral replication and attachment. This review compiles all the molecular evidence to date, in review of the antiviral characteristics exhibited by IVM. Thereafter, we discuss IVM's mechanism and highlight the clinical advantages that could potentially contribute towards disabling the viral replication of SARS-CoV-2. In summary, the collective review of recent efforts suggests that IVM has a prophylactic effect and would be a strong candidate for clinical trials to treat SARS-CoV-2.
    Matched MeSH terms: Virus Replication/drug effects*
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