Orally administered Salacia reticulata extract reduces H1N1 influenza clinical symptoms in murine lung tissues putatively due to enhanced natural killer cell activity

Gustavo A. Romero-Pérez, Masayo Egashira, Yuri Harada, Takeshi Tsuruta, Yuriko Oda, Fumitaka Ueda, Takamitsu Tsukahara, Yasuhiro Tsukamoto, Ryo Inoue

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

Influenza is a major cause of respiratory tract infection. Although most cases do not require further hospitalization, influenza periodically causes epidemics in humans that can potentially infect and kill millions of people. To countermeasure this threat, new vaccines need to be developed annually to match emerging influenza viral strains with increased resistance to existing vaccines. Thus, there is a need for finding and developing new anti-influenza viral agents as alternatives to current treatments. Here, we tested the antiviral effects of an extract from the stems and roots of Salacia reticulata (SSRE), a plant rich in phytochemicals, such as salacinol, kotalanol, and catechins, on H1N1 influenza virus-infected mice. Following oral administration of 0.6 mg/day of SSRE, the incidence of coughing decreased in 80% of mice, and only one case of severe pulmonary inflammation was detected. Moreover, when compared with mice given Lactobacillus casei JCM1134, a strain previously shown to help increase in vitro natural killer (NK) cell activity, SSRE-administered mice showed greater and equal NK cell activity in splenocytes and pulmonary cells, respectively, at high effector cell:target cell ratios. Next, to test whether or not SSRE would exert protective effects against influenza in the absence of gut microbiota, mice were given antibiotics before being inoculated influenza virus and subsequently administered SSRE. SSRE administration induced an increase in NK cell activity in splenocytes and pulmonary cells at levels similar to those detected in mice not treated with antibiotics. Based on our results, it can be concluded that phytochemicals in the SSRE exerted protective effects against influenza infection putatively via modulation of the immune response, including enhancement of NK cell activity, although some protective effects were not necessarily through modulation of gut microbiota. Further investigation is necessary to elucidate the molecular mechanisms underlying the protective effects of SSRE against influenza infection.

Original languageEnglish
Article number115
JournalFrontiers in Immunology
Volume7
Issue numberMAR
DOIs
Publication statusPublished - Mar 31 2016
Externally publishedYes

Fingerprint

Salacia
Natural Killer Cells
Human Influenza
Lung
Phytochemicals
Orthomyxoviridae
Vaccines
Anti-Bacterial Agents
Lactobacillus casei
H1N1 Subtype Influenza A Virus
Catechin
Infection
Respiratory Tract Infections
Antiviral Agents
Oral Administration
Pneumonia
Hospitalization

Keywords

  • Antibiotics
  • Gut microbiota
  • H1N1 influenza virus
  • Lactobacillus casei JCM1134
  • Natural killer cells
  • Pulmonary cells
  • Salacia reticulata extract
  • Splenocytes

ASJC Scopus subject areas

  • Immunology
  • Immunology and Allergy

Cite this

Orally administered Salacia reticulata extract reduces H1N1 influenza clinical symptoms in murine lung tissues putatively due to enhanced natural killer cell activity. / Romero-Pérez, Gustavo A.; Egashira, Masayo; Harada, Yuri; Tsuruta, Takeshi; Oda, Yuriko; Ueda, Fumitaka; Tsukahara, Takamitsu; Tsukamoto, Yasuhiro; Inoue, Ryo.

In: Frontiers in Immunology, Vol. 7, No. MAR, 115, 31.03.2016.

Research output: Contribution to journalArticle

Romero-Pérez, Gustavo A. ; Egashira, Masayo ; Harada, Yuri ; Tsuruta, Takeshi ; Oda, Yuriko ; Ueda, Fumitaka ; Tsukahara, Takamitsu ; Tsukamoto, Yasuhiro ; Inoue, Ryo. / Orally administered Salacia reticulata extract reduces H1N1 influenza clinical symptoms in murine lung tissues putatively due to enhanced natural killer cell activity. In: Frontiers in Immunology. 2016 ; Vol. 7, No. MAR.
@article{ab389c8e1e8e40d3a45e225897d42661,
title = "Orally administered Salacia reticulata extract reduces H1N1 influenza clinical symptoms in murine lung tissues putatively due to enhanced natural killer cell activity",
abstract = "Influenza is a major cause of respiratory tract infection. Although most cases do not require further hospitalization, influenza periodically causes epidemics in humans that can potentially infect and kill millions of people. To countermeasure this threat, new vaccines need to be developed annually to match emerging influenza viral strains with increased resistance to existing vaccines. Thus, there is a need for finding and developing new anti-influenza viral agents as alternatives to current treatments. Here, we tested the antiviral effects of an extract from the stems and roots of Salacia reticulata (SSRE), a plant rich in phytochemicals, such as salacinol, kotalanol, and catechins, on H1N1 influenza virus-infected mice. Following oral administration of 0.6 mg/day of SSRE, the incidence of coughing decreased in 80{\%} of mice, and only one case of severe pulmonary inflammation was detected. Moreover, when compared with mice given Lactobacillus casei JCM1134, a strain previously shown to help increase in vitro natural killer (NK) cell activity, SSRE-administered mice showed greater and equal NK cell activity in splenocytes and pulmonary cells, respectively, at high effector cell:target cell ratios. Next, to test whether or not SSRE would exert protective effects against influenza in the absence of gut microbiota, mice were given antibiotics before being inoculated influenza virus and subsequently administered SSRE. SSRE administration induced an increase in NK cell activity in splenocytes and pulmonary cells at levels similar to those detected in mice not treated with antibiotics. Based on our results, it can be concluded that phytochemicals in the SSRE exerted protective effects against influenza infection putatively via modulation of the immune response, including enhancement of NK cell activity, although some protective effects were not necessarily through modulation of gut microbiota. Further investigation is necessary to elucidate the molecular mechanisms underlying the protective effects of SSRE against influenza infection.",
keywords = "Antibiotics, Gut microbiota, H1N1 influenza virus, Lactobacillus casei JCM1134, Natural killer cells, Pulmonary cells, Salacia reticulata extract, Splenocytes",
author = "Romero-P{\'e}rez, {Gustavo A.} and Masayo Egashira and Yuri Harada and Takeshi Tsuruta and Yuriko Oda and Fumitaka Ueda and Takamitsu Tsukahara and Yasuhiro Tsukamoto and Ryo Inoue",
year = "2016",
month = "3",
day = "31",
doi = "10.3389/fimmu.2016.00115",
language = "English",
volume = "7",
journal = "Frontiers in Immunology",
issn = "1664-3224",
publisher = "Frontiers Media S. A.",
number = "MAR",

}

TY - JOUR

T1 - Orally administered Salacia reticulata extract reduces H1N1 influenza clinical symptoms in murine lung tissues putatively due to enhanced natural killer cell activity

AU - Romero-Pérez, Gustavo A.

AU - Egashira, Masayo

AU - Harada, Yuri

AU - Tsuruta, Takeshi

AU - Oda, Yuriko

AU - Ueda, Fumitaka

AU - Tsukahara, Takamitsu

AU - Tsukamoto, Yasuhiro

AU - Inoue, Ryo

PY - 2016/3/31

Y1 - 2016/3/31

N2 - Influenza is a major cause of respiratory tract infection. Although most cases do not require further hospitalization, influenza periodically causes epidemics in humans that can potentially infect and kill millions of people. To countermeasure this threat, new vaccines need to be developed annually to match emerging influenza viral strains with increased resistance to existing vaccines. Thus, there is a need for finding and developing new anti-influenza viral agents as alternatives to current treatments. Here, we tested the antiviral effects of an extract from the stems and roots of Salacia reticulata (SSRE), a plant rich in phytochemicals, such as salacinol, kotalanol, and catechins, on H1N1 influenza virus-infected mice. Following oral administration of 0.6 mg/day of SSRE, the incidence of coughing decreased in 80% of mice, and only one case of severe pulmonary inflammation was detected. Moreover, when compared with mice given Lactobacillus casei JCM1134, a strain previously shown to help increase in vitro natural killer (NK) cell activity, SSRE-administered mice showed greater and equal NK cell activity in splenocytes and pulmonary cells, respectively, at high effector cell:target cell ratios. Next, to test whether or not SSRE would exert protective effects against influenza in the absence of gut microbiota, mice were given antibiotics before being inoculated influenza virus and subsequently administered SSRE. SSRE administration induced an increase in NK cell activity in splenocytes and pulmonary cells at levels similar to those detected in mice not treated with antibiotics. Based on our results, it can be concluded that phytochemicals in the SSRE exerted protective effects against influenza infection putatively via modulation of the immune response, including enhancement of NK cell activity, although some protective effects were not necessarily through modulation of gut microbiota. Further investigation is necessary to elucidate the molecular mechanisms underlying the protective effects of SSRE against influenza infection.

AB - Influenza is a major cause of respiratory tract infection. Although most cases do not require further hospitalization, influenza periodically causes epidemics in humans that can potentially infect and kill millions of people. To countermeasure this threat, new vaccines need to be developed annually to match emerging influenza viral strains with increased resistance to existing vaccines. Thus, there is a need for finding and developing new anti-influenza viral agents as alternatives to current treatments. Here, we tested the antiviral effects of an extract from the stems and roots of Salacia reticulata (SSRE), a plant rich in phytochemicals, such as salacinol, kotalanol, and catechins, on H1N1 influenza virus-infected mice. Following oral administration of 0.6 mg/day of SSRE, the incidence of coughing decreased in 80% of mice, and only one case of severe pulmonary inflammation was detected. Moreover, when compared with mice given Lactobacillus casei JCM1134, a strain previously shown to help increase in vitro natural killer (NK) cell activity, SSRE-administered mice showed greater and equal NK cell activity in splenocytes and pulmonary cells, respectively, at high effector cell:target cell ratios. Next, to test whether or not SSRE would exert protective effects against influenza in the absence of gut microbiota, mice were given antibiotics before being inoculated influenza virus and subsequently administered SSRE. SSRE administration induced an increase in NK cell activity in splenocytes and pulmonary cells at levels similar to those detected in mice not treated with antibiotics. Based on our results, it can be concluded that phytochemicals in the SSRE exerted protective effects against influenza infection putatively via modulation of the immune response, including enhancement of NK cell activity, although some protective effects were not necessarily through modulation of gut microbiota. Further investigation is necessary to elucidate the molecular mechanisms underlying the protective effects of SSRE against influenza infection.

KW - Antibiotics

KW - Gut microbiota

KW - H1N1 influenza virus

KW - Lactobacillus casei JCM1134

KW - Natural killer cells

KW - Pulmonary cells

KW - Salacia reticulata extract

KW - Splenocytes

UR - http://www.scopus.com/inward/record.url?scp=84964677877&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84964677877&partnerID=8YFLogxK

U2 - 10.3389/fimmu.2016.00115

DO - 10.3389/fimmu.2016.00115

M3 - Article

VL - 7

JO - Frontiers in Immunology

JF - Frontiers in Immunology

SN - 1664-3224

IS - MAR

M1 - 115

ER -