• Journal of Microbiology and Biotechnology
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• v.14 no.5
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• pp.1086-1088
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• 2004

Betulin, a pentacyclic triterpenoid isolated from the bark of Betula papyrifera. Laboratory synthesized structural analogs were tested for antiviral activities against Epstein-Barr Virus (EBV) by immunofluorescent antiviral assay. Among the several analogs tested, betulin 3,28-diphosphate and uvaol exhibited significant antiviral activities against EBV. The $EC_{50}$ of betulin 3,28-diphosphate and uvaol was found to be $0.6\mu{M}$ and $0.7\mu{M}$ respectively.

• YAKHAK HOEJI
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• v.50 no.2
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• pp.65-69
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• 2006

Novel 4'-hydroxymethyl branched thioapiosyl nucleosides were synthesized in this study. The introduction of hydroxymethyl group in the 4'-position was accomplished by a [3,3]-sigmatropic rearrangement. Thioapiosyl sugar moiety was constructed by sequential ozonolysis, reduction and cyclization. The pyrimidine nucleosidic bases (uracil, 5-fluorouracil, 5-iodouracil, 5-chlorouracil, 5-bromouracil) were efficiently coupled by Vorbruggen glycosyl condensation procedure (per-silyated base and TMSOTf). The antiviral activities of the synthesised compounds were evaluated against the HIV-1, HSV-1, HSV-2 and EMCV 5-Iodouracil 18 showed weak antiviral activity against HSV-1 $(EC_{50}=30.7{\mu}M)$.

• Journal of Integrative Natural Science
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• v.8 no.3
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• pp.153-163
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• 2015

Racemic synthesis of novel 5',5'-difluoro-2'-methyl-apiose nucleoside phosphonic acid analogs was achieved as potent antiviral agents. Phosphonation was performed by direct displacement of triflate intermediate with diethyl (lithiodifluoromethyl) phosphonate to give the corresponding (${\alpha},{\alpha}$-difluoroalkyl) phosphonate. Condensation successfully proceeded from a glycosyl donor with persilylated bases to yield the nucleoside phosphonate analogs. Deprotection of diethyl phosphonates provided the target nucleoside analogs. An antiviral evaluation of the synthesized compounds against various viruses such as HIV, HSV-1, HSV-2 and HCMV revealed that the pyrimidine analogs (cytosine, uracil, and thymine) have weak anti-HIV or HCMV activity.

• Journal of Integrative Natural Science
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• v.8 no.2
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• pp.99-106
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• 2015

Novel 2'(${\beta}$)-fluoro-3'(${\alpha}$)-hydroxy-threose nucleosides (iso-FMAU) as antiviral agents were designed and racemically synthesized from Solketal. Condensation successfully proceeded from a glycosyl donor 9 under $Vorbr{\ddot{u}}ggen$ conditions yielded the nucleoside analogues. Ammonolysis and hydrolysis of isopropylidene protection group gave the desired nucleoside analogues 12, 15, 18, and 19. The antiviral activities of the synthesized compounds were evaluated against the HIV-1, HSV-1, HSV-2 and HCMV. Compound 12 displayed some anti-HCMV activity ($EC_{50}=24.7{\mu}g/ml$) without exhibiting any cytotoxicity up to $100{\mu}M$.

• YAKHAK HOEJI
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• v.51 no.2
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• pp.103-107
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• 2007

In these study novel 1,4-disubstituted carbocyclic nucleoside analogues were synthesized as potential antiviral agents. The coupling reaction of the alcohol 8${\alpha}$ with natural bases using Mitsunobu reaction afforded the target nucleosides 13, 14. The synthesized compounds were evaluated for their antiviral activity against various viruses such as HIV-1, HSV-1, HSV-2 and HCMV. Cytosine derivative 13 exhibited moderate antiviral activity against HIV-1 (EC$_{50}$=16.4 ${\mu}$M).

• Journal of Pharmacopuncture
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• v.23 no.2
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• pp.62-70
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• 2020

Coronavirus disease-19 (COVID-19) is caused by the severe acute respiratory syndrome coronavirus 2 (SARS CoV-2). Currently, the management of patients with COVID-19 depends mainly on repurposed drugs which include chloroquine, hydroxychloroquine, lopinavir/ritonavir, ribavirin, remdesivir, favipiravir, umifenovir, interferon-α, interferon-β and others. In this review, the potential of Nigella sativa (black cumin seeds) to treat the patients with COVID-19 analyzed, as it has shown to possess antiviral, antioxidant, anti-inflammatory, anticoagulant, immunomodulatory, bronchodilatory, antihistaminic, antitussive, antipyretic and analgesic activities. Medline/PubMed Central/PubMed, Google Scholar, Science Direct, Directory of open access journals (DOAJ) and reference lists were searched to identify articles associated with antiviral and other properties of N.sativa related to the signs and symptoms of COVID-19. Various randomized controlled trials, pilot studies, case reports and in vitro and in vivo studies confirmed that N.sativa has antiviral, antioxidant, anti-inflammatory, immunomodulatory, bronchodilatory, antihistaminic, antitussive activities related to causative oraganism and signs and symptoms of COVID-19. N. sativa could be used as an adjuvant therapy along with repurposed conventional drugs to manage the patients with COVID-19.

• Fisheries and Aquatic Sciences
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• v.13 no.2
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• pp.96-101
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• 2010

Norovirus, which causes gastroenteritis in humans, is an important food-borne pathogen worldwide. In an effort to discover an antiviral substance against norovirus, extracts from several seaweeds were evaluated for antiviral activity against feline calicivirus (FCV), which was used as a surrogate. The methanolic extract of Undaria pinnatifida exhibited the most significant antiviral activity and virucidal efficacy against FCV. The concentrations of the extract that reduced viral replication by 50% ($EC_{50}$) and resulted in the death of 50% of the host cells ($CC_{50}$) were 0.05 mg/mL and 1.02 mg/mL, respectively. The selectivity index, calculated from the ratio of the $CC_{50}$ and $EC_{50}$ was 20.4. No FCV infection of host cells occurred following a 1-h incubation in the presence of 12.50 mg/mL U. pinnatifida extract, indicating that the virus was completely inactivated by the extract treatment. The results obtained in this study will contribute to the development of a natural antiviral substance that will prevent food-borne disease caused by norovirus.

• Korean Journal of Microbiology
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• v.38 no.4
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• pp.255-255
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• 2002

For rapid and sensitive measurement of antiviral activities, application of a recombinant virus containing firefly luciferase gene was attempted. Recombinant human cytomegalovirus (HCMV) containing luciferase gene driven by HCMV late gene pp28 promoter (HCMV/pp28-luc) was used to test the antiviral activities of three known compounds and the result was compared with results from the conventional plaque assay for measuring the production of infectious viruses. When human fibroblast cells were infected with HCMV/pp28-luc, luciferase activity was observed at 2 days after infection and reached maximum at 6 days after infection, whereas the production of infectious virus was maximal at 4 days after infection. The antiviral activities of ganciclovir, acyclovir, and papaverine were measured in HFF cells infected with HCMV/PP28-luc and the luciferase activity was compared with the infectious virus titers. Luciferase activity decreased as the concentration of ganciclovir or papaverine increased, while there was a slight decrease in luciferase activity with acyclovir. The level of the decrease in Luciferase activity was comparable to the level of decrease in the production of infectious virus. Therefore, the antiviral assay using recombinant virus HCMV/pp28-luc resulted in sensitivity similar to the conventional plaque assay with a significant reduction in assay time.

• Biomolecules & Therapeutics
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• v.22 no.1
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• pp.41-46
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• 2014

Enterovirus 71 (EV71) is the predominant cause of hand, foot and mouth disease (HFMD). The antiviral activity of hederasaponin B from Hedera helix against EV71 subgenotypes C3 and C4a was evaluated in vero cells. In the current study, the antiviral activity of hederasaponin B against EV71 C3 and C4a was determined by cytopathic effect (CPE) reduction method and western blot assay. Our results demonstrated that hederasaponin B and 30% ethanol extract of Hedera helix containing hederasaponin B showed significant antiviral activity against EV71 subgenotypes C3 and C4a by reducing the formation of a visible CPE. Hederasaponin B also inhibited the viral VP2 protein expression, suggesting the inhibition of viral capsid protein synthesis.These results suggest that hederasaponin B and Hedera helix extract containing hederasaponin B can be novel drug candidates with broad-spectrum antiviral activity against various subgenotypes of EV71.

• Biomolecules & Therapeutics
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• v.23 no.5
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• pp.465-470
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• 2015

Chrysin is a 5,7-dihydroxyflavone and was recently shown to potently inhibit enterovirus 71 (EV71) by suppressing viral 3C protease ($3C^{pro}$ activity. In the current study, we investigated whether chrysin also shows antiviral activity against coxsackievirus B3 (CVB3), which belongs to the same genus (Enterovirus) as EV71, and assessed its ability to prevent the resulting acute pancreatitis and myocarditis. We found that chrysin showed antiviral activity against CVB3 at $10{\mu}M$, but exhibited mild cellular cytotoxicity at $50{\mu}M$, prompting us to synthesize derivatives of chrysin to increase the antiviral activity and reduce its cytotoxicity. Among four 4-substituted benzyl derivatives derived from C(5) benzyl-protected derivatives 7, 9-11 had significant antiviral activity and showed the most potent activity against CVB3 with low cytotoxicity in Vero cells. Intraperitoneal injection of CVB3 in BALB/c mice with $1{\times}10^6TCID_{50}$ (50% tissue culture infective dose) of CVB3 induced acute pancreatitis with ablation of acinar cells and increased serum CXCL1 levels, whereas the daily administration of 9 for 5 days significantly alleviated the pancreatic inflammation and reduced the elevation in serum CXCL1 levels. Collectively, we assessed the anti-CVB3 activities of chrysin and its derivatives, and found that among 4-substituted benzyl derivatives, 9 exhibited the highest activity against CVB3 in vivo, and protected mice from CVB3-induced pancreatic damage, simultaneously lowering serum CXCL1 levels.