Sambucus nigra extracts inhibit infectious bronchitis virus at an early point during replication

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.

Plants-Derived Biomolecules as Potent Antiviral Phytomedicines: New Insights on Ethnobotanical Evidences against Coronaviruses

“…This plant belongs to the family of Caprrifoliaceae and is mostly used in the treatment of common cold, HIV, HSV-1, influenza, urinary tract infection, edema and other rheumatic diseases [ 149 , 267 ]. It contains several active components extracted from the leaves, flower and fruit parts of the plant, such as flavonoids, lectins, anthocyanin, etc., which have been found to increase the immunity and inhibit the viral activity [ 150 , 152 , 153 , 154 ]. However, in case of the H1N1 influenza virus, this plant has shown great potential to block or impede the entry of the virus into the host cells [ 149 , 155 , 268 ].…”

Plants, people and traditions: ethnobotanical survey in the Lombard Stelvio National Park and neighbouring areas (Central Alps, Italy)

“…Previous studies validated some of these traditional uses: Chelidonium majus (keratolytic) (Doudi and Setorki, 2014); Valeriana officinalis (sedative) (Maroo et al, 2013;Patidar et al, 2012); Cetraria islandica (antimicrobial) (Grujicˇic et al, 2014); Gentiana lutea (digestive) (McMullen et al, 2014); Melissa officinalis (sedative) (Ghayour et al, 2012;Miladi-Gorji et al, 2011); Hypericum perforatum (antimicrobic and anti-inflammatory) (Iabichella, 2015); Matricaria chamomilla (sedative) (Kesmati et al, 2009); Sambucus nigra (antiviral and antimicrobial) (Chen et al, 2014;Kravitz et al, 2011); Solanum tuberosum (eye anti-inflammatory) (Umadevi et al, 2013); Allium sativum (hypotensive) 2012); Thymus sp. (antibacterial) (Kavita et al, 2011); Arnica montana (analgesic and anti-inflammatory) (Gaspar et al, 2014;Cassu et al, 2011).…”

Antiviral Medicinal Plants of Veterinary Importance: A Literature Review

“…It is a highly infectious avian pathogen that affects the respiratory tract, gut, kidneys, and reproductive system of chickens. The aqueous extract of A. sativum L. (Amaryllidaceae) [76], the ethanolic (80 %) extract of Sambucus nigra L. (Adoxaceae) [77], polysaccharides of Astragalus species [78], and the essential oil of Rosmarinus officinalis L. (Lamiaceae) [79] were determined to be active against IBV in vitro. Furthermore, theaflavins of C. sinensis (L.) Kuntze (Theaceae) exhibited activity against BCV [75].…”