Abstract

BackgroundInfectious 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.ResultsDose–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.ConclusionsThese 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.

Highlights

  • Infectious bronchitis virus (IBV) is a pathogenic chicken coronavirus

  • These results demonstrate that S. nigra extract can inhibit IBV at an early point in infection, probably by rendering the virus non-infectious

  • They suggest that future studies using S. nigra extract to treat or prevent IBV or other coronaviruses are warranted

Read more

Summary

Introduction

Infectious bronchitis virus (IBV) is a pathogenic chicken coronavirus. Currently, vaccination against IBV is only partially protective; better preventions and treatments are needed. Some of the bestknown examples include quinine isolated from Cinchona pubescens (Cinchona tree) for treating malaria, digoxin from Digitalis purpurea (foxglove) for treating cardiac conditions, morphine from Papaver somniferum (opium poppy) used for pain, and aspirin synthesized from the bark of various Salix (willow) species In many of these cases, the active chemicals isolated from these plants have been the basis for developing additional medications that are used today. Ingestion of or gargling with catechin-containing plant extracts results in lower rates of influenza virus infection [16,17]. Quercetin is another secondary metabolite involved in plant and animal pathogen defense. In vitro and in vivo studies have both shown that quercetin and its derivatives inhibit influenza virus and poliovirus replication, while in vitro treatment of the human pathogen, Salmonella enterica, results in microbe death [19,20,21,22,23,24]

Methods
Results
Discussion
Conclusion
Full Text
Published version (Free)

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call