• Biomolecules & Therapeutics
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• 제23권4호
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• pp.345-349
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• 2015

Betulinic acid, a pentacyclic triterpene isolated from Jujube tree (Zizyphus jujuba Mill), has been known for a wide range of biological and medicinal properties such as antibacterial, antimalarial, anti-inflammatory, antihelmintic, antinociceptive, and anticancer activities. In the study, we investigated the antiviral activity on influenza A/PR/8 virus infected A549 human lung adenocarcinoma epithelial cell line and C57BL/6 mice. Betulinic acid showed the anti-influenza viral activity at a concentration of $50{\mu}M$ without a significant cytotoxicity in influenza A/PR/8 virus infected A549 cells. Also, betulinic acid significantly attenuated pulmonary pathology including increased necrosis, numbers of inflammatory cells and pulmonary edema induced by influenza A/PR/8 virus infection compared with vehicle- or oseltamivir-treated mice in vivo model. The down-regulation of IFN-${\gamma}$ level, which is critical for innate and adaptive immunity in viral infection, after treating of betulinic acid in mouse lung. Based on the obtained results, it is suggested that betulinic acid can be the potential therapeutic agent for virus infection via anti-inflammatory activity.

• Journal of Microbiology and Biotechnology
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• 제23권1호
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• pp.125-130
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• 2013

Influenza viruses cause significant morbidity and mortality in humans through epidemics or pandemics. Currently, two classes of anti-influenza virus drugs, M2 ion-channel inhibitors (amantadin and rimantadine) and neuraminidase inhibitors (oseltamivir and zanamivir), have been used for the treatment of the influenza virus infection. Since the resistance to these drugs has been reported, the development of a new antiviral agent is necessary. In this study, we examined the antiviral efficacy of the plant extracts against the influenza A/PR/8/34 infection. In vitro, the antiviral activities of the plant extracts were investigated using the cell-based screening. Three plant extracts, Thuja orientalis, Aster spathulifolius, and Pinus thunbergii, were shown to induce a high cell viability rate after the infection with the influenza A/PR/8/34 virus. The antiviral activity of the plant extracts also increased as a function of the concentration of the extracts and these extracts significantly reduced the visible cytopathic effect caused by virus infections. Furthermore, the treatment with T. orientalis was shown to have a stronger inhibitory effect than that with A. spathulifolius or P. thunbergii. These results may suggest that T. orientalis has anti-influenza A/PR/8/34 activity.

• IMMUNE NETWORK
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• 제20권4호
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• pp.32.1-32.15
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• 2020

Influenza virus is the major cause of seasonal and pandemic flu. Currently, oseltamivir, a potent and selective inhibitor of neuraminidase of influenza A and B viruses, is the drug of choice for treating patients with influenza virus infection. However, recent emergence of oseltamivir-resistant influenza viruses has limited its efficacy. Morin hydrate (3,5,7,2',4'-pentahydroxyflavone) is a flavonoid isolated from Morus alba L. It has antioxidant, anti-inflammatory, neuroprotective, and anticancer effects partly by the inhibition of the NF-κB signaling pathway. However, its effects on influenza virus have not been studied. We evaluated the antiviral activity of morin hydrate against influenza A/Puerto Rico/8/1934 (A/PR/8; H1N1) and oseltamivir-resistant A/PR/8 influenza viruses in vitro. To determine its mode of action, we carried out time course experiments, and time of addition, hemolysis inhibition, and hemagglutination assays. The effects of the co-administration of morin hydrate and oseltamivir were assessed using the murine model of A/PR/8 infection. We found that morin hydrate reduced hemagglutination by A/PR/8 in vitro. It alleviated the symptoms of A/PR/8-infection, and reduced the levels of pro-inflammatory cytokines and chemokines, such as TNF-α and CCL2, in infected mice. Co-administration of morin hydrate and oseltamivir phosphate reduced the virus titers and attenuated pulmonary inflammation. Our results suggest that morin hydrate exhibits antiviral activity by inhibiting the entry of the virus.

• Journal of Microbiology and Biotechnology
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• 제31권2호
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• pp.304-316
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• 2021

Vaccination is the most effective way to prevent influenza virus infections. However, conventional vaccines based on hemagglutinin (HA) have to be annually updated because the HA of influenza viruses constantly mutates. In this study, we produced a 3M2e-3HA2-NP chimeric protein as a vaccine antigen candidate using an Escherichia coli expression system. The vaccination of chimeric protein (15 ㎍) conferred complete protection against A/Puerto Rico/8/1934 (H1N1; PR8) in mice. It strongly induced influenza virus-specific antibody responses, cytotoxic T lymphocyte activity, and antibody-dependent cellular cytotoxicity. To spare the dose and enhance the cross-reactivity of the chimeric, we used a complex of poly-γ-glutamic acid and alum (PGA/alum) as an adjuvant. PGA/alum-adjuvanted, low-dose chimeric protein (1 or 5 ㎍) exhibited higher cross-protective effects against influenza A viruses (PR8, CA04, and H3N2) compared with those of chimeric alone or alum-adjuvanted proteins in vaccinated mice. Moreover, the depletion of CD4+ T, CD8+ T, and NK cells reduced the survival rate and efficacy of the PGA/alum-adjuvanted chimeric protein. Collectively, the vaccination of PGA/alum-adjuvanted chimeric protein induced strong protection efficacy against homologous and heterologous influenza viruses in mice, which suggests that it may be a promising universal influenza vaccine candidate.

• IMMUNE NETWORK
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• 제12권6호
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• pp.261-268
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• 2012

Respiratory syncytial virus (RSV) and influenza virus are the most significant pathogens causing respiratory tract diseases. Composite vaccines are useful in reducing the number of vaccination and confer protection against multiple infectious agents. In this study, we generated fusion of RSV G protein core fragment (amino acid residues 131 to 230) and influenza HA1 globular head domain (amino acid residues 62 to 284) as a dual vaccine candidate. This fusion protein, Gcf-HA1, was bacterially expressed, purified by metal resin affinity chromatography, and refolded in PBS. BALB/c mice were intranasally immunized with Gcf-HA1 in combination with a mucosal adjuvant, cholera toxin (CT). Both serum IgG and mucosal IgA responses specific to Gcf and HA1 were significantly increased in Gcf-HA1/CT-vaccinated mice. To determine the protective efficacy of Gcf-HA1/CT vaccine, immunized mice were challenged with RSV (A2 strain) or influenza virus (A/PR/8/34). Neither detectable viral replication nor pathology was observed in the lungs of the immune mice. These results demonstrate that immunity induced by intranasal Gcf-HA1/CT immunization confers complete protection against both RSV and homologous influenza virus infection, suggesting our Gcf-HA1 vaccine candidate could be further developed as a dual subunit vaccine against RSV and influenza virus.

• Journal of Microbiology and Biotechnology
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• 제28권6호
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• pp.997-1006
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• 2018

As shown during the 2009 pandemic H1N1 (A(H1N1)pdm09) outbreak, egg-based influenza vaccine production technology is insufficient to meet global demands during an influenza pandemic. Therefore, there is a need to adapt cell culture-derived vaccine technology using suspended cell lines for more rapid and larger-scale vaccine production. In this study, we attempted to generate a high-growth influenza vaccine strain in MDCK cells using an A/Puerto/8/1934 (H1N1) vaccine seed strain. Following 48 serial passages with four rounds of virus plaque purification in MDCK cells, we were able to select several MDCK-adapted plaques that could grow over $10^8PFU/ml$. Genetic characterization revealed that these viruses mainly had amino acid substitutions in internal genes and exhibited higher polymerase activities. By using a series of Rg viruses, we demonstrated the essential residues of each gene and identified a set of high-growth strains in MDCK cells ($PB1_{D153N}$, $M1_{A137T}$, and $NS1_{N176S}$). In addition, we confirmed that in the context of the high-growth A/PR/8/34 backbone, A/California/7/2009 (H1N1), A/Perth/16/2009 (H3N2), and A/environment/Korea/deltaW150/2006 (H5N1) also showed significantly enhanced growth properties (more than $10^7PFU/ml$) in both attached- and suspended-MDCK cells compared with each representative virus and the original PR8 vaccine strain. Taken together, this study demonstrates the feasibility of a cell culture-derived approach to produce seed viruses for influenza vaccines that are cheap and can be grown promptly and vigorously as a substitute for egg-based vaccines. Thus, our results suggest that MDCK cell-based vaccine production is a feasible option for producing large-scale vaccines in case of pandemic outbreaks.

• International Journal of Advanced Culture Technology
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• 제7권3호
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• pp.120-125
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• 2019

In this paper, we have isolated six phenolic compounds, such as (+)-catechin (1), taxifolin (2), taxifolin-3-O-${\beta}$-D-(+)-xylose (3), quercetin (4), quercetin-3-O-${\alpha}$-L(+)-rhamnose (quercitrin) (5), apigenin-8-C-rhamnosyl-(1'''${\rightarrow}$2'')-glucoside (2''-O-rhamnosylvitexin) (6) from the EtOAc(Ethyl Acetate) and $H_2O$ soluble fractions of Japanese anise(Illicium anisatum L) leaves and twigs. Also, we have evaluated antioxidative and antiviral activity for each isolated compound. The antioxidative test was DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging activity. According to the experimental results, all of the isolated compounds indicated the increased radical scavenging activities as the concentration increases and most of the isolated compounds indicated generally good antioxidative values compare to the controls, ascorbic acid and ${\alpha}$-tocopherol. In the antiviral activities, all of the isolated compounds had no potentials in rhinovirus 1B (HRV 1B). But in enterovirus 71 (EV 71) and Influenza virus A/PR/8 (Influenza PR8), only quercetin (4) indicated the good antiviral activity compare to the control. Based on the above results, we found that the phenolic compounds of Japanese anise may be applied for one of the natural biomass sources that can be used as an antioxidant and an antiviral substance.

• 한국약용작물학회지
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• 제16권4호
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• pp.273-278
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• 2008

We aimed to investigate the antiviral activity of Zanthoxylum species against influenza virus A/WS/33, A/PR/8 and B/Lee/40 used by sulforhodamine B (SRB) assay and the action of leaves extracts of Zanthoxylum piperitum on life cycle of influenza virus A/WS/33. Among the twelve extracts, only the leaf extract of Z. piperitum exhibited strong antiviral activity at low concentration of less than 10${\mu}g/m{\ell}$ with no citotoxicity (50${\mu}g/m{\ell}$) against all of three viruses. In addition, only oseltamivir showed antiviral activity with $IC_{50}$ of 65.3${\mu}g/m{\ell}$ against influenza A/WS/33 among the viruses. Furthermore, the leaf extract of Z. piperitum suppressed infection of influenza virus A/WS/33, when added just prior (-1 hr) or after virus inoculation (0 hr). Leaf extract of Z. piperitum directly affect the infectivity of influenza virus A/WS/33 particles. Therefore, Leaf extract of Z. piperitum exhibited higher antiviral activity against three influenza viruses than that of the oseltamivir, which directly interacts with influenza A/WS/33 particles, affecting the initial stages of infection such as receptor binding and virus entry.

• Journal of Microbiology and Biotechnology
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• 제30권2호
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• pp.172-177
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• 2020

Influenza viruses cause respiratory diseases in humans and animals with high morbidity and mortality rates. Conventional anti-influenza drugs are reported to exert side effects and newly emerging viral strains tend to develop resistance to these commonly used agents. Fritillaria thunbergii (FT) is traditionally used as an expectorant for controlling airway inflammatory disorders. Here, we evaluated the therapeutic effects of FT extracts against influenza virus type A (H1N1) infection in vitro, in ovo, and in vivo. In the post-treatment assay, FT extracts showed high CC50 (7,500 ㎍/ml), indicating low toxicity, and exerted moderate antiviral effects compared to oseltamivir (SI 50.6 vs. 222) in vitro. Antiviral activity tests in ovo revealed strong inhibitory effects of both FT extract and oseltamivir against H1N1 replication in embryonated eggs. Notably, at a treatment concentration of 150 mg/kg, only half the group administered oseltamivir survived whereas the FT group showed 100% survival, clearly demonstrating the low toxicity of FT extracts. Consistent with these findings, FT-administered mice showed a higher survival rate with lower body weight reduction relative to the oseltamivir group upon treatment 24 h after viral infection. Our collective results suggest that FT extracts exert antiviral effects against influenza H1N1 virus without inducing toxicity in vitro, in ovo or in vivo, thereby supporting the potential utility of FT extract as a novel candidate therapeutic drug or supplement against influenza.

• 한국식품영양과학회지
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• 제29권1호
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• pp.128-133
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• 2000

This study was designed to verify the efficacy of garlic extracts for protecting the infecton of influenza and Japanese B encephalitis virus. Influenza virus (AO/PR8 strain) and Japanese B encephalitis virus (JaGAr O1 strain) were used to attack mouse through nasal route and each vaccines were injected subcutaneously. 0.002 and 0.2 mL/day of garlic extracts were orally administered to mice. The blood and serum samples were taken from the mice to measure LD50, Defense Index (DI), virus-neutralizing antibody for comparing virus influence inhibiting activities. Defense indices of the male and female mice were not significantly different at every experiment. Vaccination effectively inhibited the influence of influenza virus and 0.002 mL/day garlic extract (0.55$\pm$0.05) resulted in significantly higher DI than the control (0$\pm$0.05) (p<0.05). Although 0.002 mL/day garlic extract (0.55$\pm$0.05) resulted in significantly lower DI than the vaccination (1.10$\pm$0.05), 0.2 mL/day garlic extract (2.05$\pm$0.05) resulted in 10 times higher DI than the vaccination (1.10$\pm$0.05). Garlic extract did not affect DI in Japanese B encephalitis virus influence of the vaccinated mouse, but significantly reduced DI of the non-vaccinated mouse (p<0.05). Garlic extracts did not affect the production of the neutralizing antibody against influenza by vaccination. However, neutralizing antibody production of Japanese B encephalitis was accelerated by vaccination. Consequently, the current study proved the efficacy of garlic on inhibition of influenza virus. Finally, it is very hard to show the higher preventing effect on flu through ingestion of garlic as a food than vaccination.