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Antiviral Activity and Underlying Action Mechanism of Euglena Extract against Influenza Virus

It is difficult to match annual vaccines against the exact influenza strain that is spreading in any given flu season. Owing to the emergence of drug-resistant viral strains, new approaches for treating influenza are needed. Euglena gracilis (hereinafter Euglena), microalga, used as functional foods...

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Autores principales: Nakashima, Ayaka, Horio, Yuka, Suzuki, Kengo, Isegawa, Yuji
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8624635/
https://www.ncbi.nlm.nih.gov/pubmed/34836165
http://dx.doi.org/10.3390/nu13113911
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author Nakashima, Ayaka
Horio, Yuka
Suzuki, Kengo
Isegawa, Yuji
author_facet Nakashima, Ayaka
Horio, Yuka
Suzuki, Kengo
Isegawa, Yuji
author_sort Nakashima, Ayaka
collection PubMed
description It is difficult to match annual vaccines against the exact influenza strain that is spreading in any given flu season. Owing to the emergence of drug-resistant viral strains, new approaches for treating influenza are needed. Euglena gracilis (hereinafter Euglena), microalga, used as functional foods and supplements, have been shown to alleviate symptoms of influenza virus infection in mice. However, the mechanism underlying the inhibitory action of microalgae against the influenza virus is unknown. Here, we aimed to study the antiviral activity of Euglena extract against the influenza virus and the underlying action mechanism using Madin–Darby canine kidney (MDCK) cells. Euglena extract strongly inhibited infection by all influenza virus strains examined, including those resistant to the anti-influenza drugs oseltamivir and amantadine. A time-of-addition assay revealed that Euglena extract did not affect the cycle of virus replication, and cell pretreatment or prolonged treatment of infected cells reduced the virus titer. Thus, Euglena extract may activate the host cell defense mechanisms, rather than directly acting on the influenza virus. Moreover, various minerals, mainly zinc, in Euglena extract were found to be involved in the antiviral activity of the extract. In conclusion, Euglena extract could be a potent agent for preventing and treating influenza.
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spelling pubmed-86246352021-11-27 Antiviral Activity and Underlying Action Mechanism of Euglena Extract against Influenza Virus Nakashima, Ayaka Horio, Yuka Suzuki, Kengo Isegawa, Yuji Nutrients Article It is difficult to match annual vaccines against the exact influenza strain that is spreading in any given flu season. Owing to the emergence of drug-resistant viral strains, new approaches for treating influenza are needed. Euglena gracilis (hereinafter Euglena), microalga, used as functional foods and supplements, have been shown to alleviate symptoms of influenza virus infection in mice. However, the mechanism underlying the inhibitory action of microalgae against the influenza virus is unknown. Here, we aimed to study the antiviral activity of Euglena extract against the influenza virus and the underlying action mechanism using Madin–Darby canine kidney (MDCK) cells. Euglena extract strongly inhibited infection by all influenza virus strains examined, including those resistant to the anti-influenza drugs oseltamivir and amantadine. A time-of-addition assay revealed that Euglena extract did not affect the cycle of virus replication, and cell pretreatment or prolonged treatment of infected cells reduced the virus titer. Thus, Euglena extract may activate the host cell defense mechanisms, rather than directly acting on the influenza virus. Moreover, various minerals, mainly zinc, in Euglena extract were found to be involved in the antiviral activity of the extract. In conclusion, Euglena extract could be a potent agent for preventing and treating influenza. MDPI 2021-10-30 /pmc/articles/PMC8624635/ /pubmed/34836165 http://dx.doi.org/10.3390/nu13113911 Text en © 2021 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Nakashima, Ayaka
Horio, Yuka
Suzuki, Kengo
Isegawa, Yuji
Antiviral Activity and Underlying Action Mechanism of Euglena Extract against Influenza Virus
title Antiviral Activity and Underlying Action Mechanism of Euglena Extract against Influenza Virus
title_full Antiviral Activity and Underlying Action Mechanism of Euglena Extract against Influenza Virus
title_fullStr Antiviral Activity and Underlying Action Mechanism of Euglena Extract against Influenza Virus
title_full_unstemmed Antiviral Activity and Underlying Action Mechanism of Euglena Extract against Influenza Virus
title_short Antiviral Activity and Underlying Action Mechanism of Euglena Extract against Influenza Virus
title_sort antiviral activity and underlying action mechanism of euglena extract against influenza virus
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8624635/
https://www.ncbi.nlm.nih.gov/pubmed/34836165
http://dx.doi.org/10.3390/nu13113911
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