TY - JOUR
T1 - Sambucus nigra extracts inhibit infectious bronchitis virus at an early point during replication
AU - Chen, Christie
AU - Zuckerman, David M.
AU - Brantley, Susanna
AU - Sharpe, Michka
AU - Childress, Kevin
AU - Hoiczyk, Egbert
AU - Pendleton, Amanda R.
N1 - Funding Information:
We would like to thank Dr. Carolyn Machamer of The Johns Hopkins University School of Medicine for providing us with virus and cells. This research was made possible by funding from the Howard Hughes Medical Institute (Grant No. 52005873), the Summer Undergraduate Research at Emory program, the Pierce Institute for Leadership and Community Engagement at Oxford College of Emory University, the Harrison Foundation Equipment Grant, and the President’s Supplemental Fund for Scholarship at Emory University. DMZ. and EH were supported by a grant from the National Institutes of Health (GM85024).
PY - 2014/1/16
Y1 - 2014/1/16
N2 - Background: Infectious bronchitis virus (IBV) is a pathogenic chicken coronavirus. Currently, vaccination against IBV is only partially protective; therefore, better preventions and treatments are needed. Plants produce antimicrobial secondary compounds, which may be a source for novel anti-viral drugs. Non-cytotoxic, crude ethanol extracts of Rhodiola rosea roots, Nigella sativa seeds, and Sambucus nigra fruit were tested for anti-IBV activity, since these safe, widely used plant tissues contain polyphenol derivatives that inhibit other viruses.Results: Dose-response cytotoxicity curves on Vero cells using trypan blue staining determined the highest non-cytotoxic concentrations of each plant extract. To screen for IBV inhibition, cells and virus were pretreated with extracts, followed by infection in the presence of extract. Viral cytopathic effect was assessed visually following an additional 24 h incubation with extract. Cells and supernatants were harvested separately and virus titers were quantified by plaque assay. Variations of this screening protocol determined the effects of a number of shortened S. nigra extract treatments. Finally, S. nigra extract-treated virions were visualized by transmission electron microscopy with negative staining.Virus titers from infected cells treated with R. rosea and N. sativa extracts were not substantially different from infected cells treated with solvent alone. However, treatment with S. nigra extracts reduced virus titers by four orders of magnitude at a multiplicity of infection (MOI) of 1 in a dose-responsive manner. Infection at a low MOI reduced viral titers by six orders of magnitude and pretreatment of virus was necessary, but not sufficient, for full virus inhibition. Electron microscopy of virions treated with S. nigra extract showed compromised envelopes and the presence of membrane vesicles, which suggested a mechanism of action.Conclusions: These results demonstrate that S. nigra extract can inhibit IBV at an early point in infection, probably by rendering the virus non-infectious. They also suggest that future studies using S. nigra extract to treat or prevent IBV or other coronaviruses are warranted.
AB - Background: Infectious bronchitis virus (IBV) is a pathogenic chicken coronavirus. Currently, vaccination against IBV is only partially protective; therefore, better preventions and treatments are needed. Plants produce antimicrobial secondary compounds, which may be a source for novel anti-viral drugs. Non-cytotoxic, crude ethanol extracts of Rhodiola rosea roots, Nigella sativa seeds, and Sambucus nigra fruit were tested for anti-IBV activity, since these safe, widely used plant tissues contain polyphenol derivatives that inhibit other viruses.Results: Dose-response cytotoxicity curves on Vero cells using trypan blue staining determined the highest non-cytotoxic concentrations of each plant extract. To screen for IBV inhibition, cells and virus were pretreated with extracts, followed by infection in the presence of extract. Viral cytopathic effect was assessed visually following an additional 24 h incubation with extract. Cells and supernatants were harvested separately and virus titers were quantified by plaque assay. Variations of this screening protocol determined the effects of a number of shortened S. nigra extract treatments. Finally, S. nigra extract-treated virions were visualized by transmission electron microscopy with negative staining.Virus titers from infected cells treated with R. rosea and N. sativa extracts were not substantially different from infected cells treated with solvent alone. However, treatment with S. nigra extracts reduced virus titers by four orders of magnitude at a multiplicity of infection (MOI) of 1 in a dose-responsive manner. Infection at a low MOI reduced viral titers by six orders of magnitude and pretreatment of virus was necessary, but not sufficient, for full virus inhibition. Electron microscopy of virions treated with S. nigra extract showed compromised envelopes and the presence of membrane vesicles, which suggested a mechanism of action.Conclusions: These results demonstrate that S. nigra extract can inhibit IBV at an early point in infection, probably by rendering the virus non-infectious. They also suggest that future studies using S. nigra extract to treat or prevent IBV or other coronaviruses are warranted.
KW - Coronavirus
KW - Infectious bronchitis virus
KW - Nigella sativa
KW - Rhodiola rosea
KW - Sambucus nigra
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U2 - 10.1186/1746-6148-10-24
DO - 10.1186/1746-6148-10-24
M3 - Article
C2 - 24433341
AN - SCOPUS:84892393275
SN - 1746-6148
VL - 10
JO - BMC veterinary research
JF - BMC veterinary research
M1 - 24
ER -