Ground-Breaking Study Finds Plant-Derived Antiviral to Be Effective Against COVID-19

Researchers have discovered a novel antiviral property of a drug that could have major implications in how future epidemics/pandemics - including COVID-19 - are managed.

The study by researchers from the University of Nottingham (Nottingham, UK) has shown that thapsigargin is a promising broad-spectrum antiviral, highly effective against SARS-CoV-2, a common cold coronavirus, respiratory syncytial virus (RSV) and the influenza A virus. Given that acute respiratory virus infections caused by different viruses are clinically indistinguishable on presentation, an effective broad-spectrum that can target different virus types at the same time could significantly improve clinical management. An antiviral of this type could potentially be made available for community use to control active infection and its spread.

In their ground-breaking study, the team of experts found that the plant-derived antiviral, at small doses, triggered a highly effective broad-spectrum host-centered antiviral innate immune response against three major types of human respiratory viruses – including COVID-19. The key features based on cell and animal studies, which make thapsigargin a promising antiviral are that it is effective against viral infection when used before or during active infection and is able to prevent a virus from making new copies of itself in cells for at least 48 hours after a single 30-minute exposure.

The study also found that thapsigargin was stable in acidic pH, as found in the stomach, and therefore can be taken orally, so could be administered without the need for injections or hospital admission. Thapsigargin was not found to be sensitive to virus resistance and proved at least several hundred-fold more effective than current antiviral options. The researchers found thapsigargin was just as effective in blocking combined infection with coronavirus and influenza A virus as in single-virus infection. Given that influenza virus, coronavirus and RSV are global pathogens of humans as well as animals, thapsigargin represents a lead compound in the development of a new generation of powerful host-centered antivirals (as opposed to conventional antiviral drugs that directly target viruses) that could even be adopted in a holistic "One Health" approach to control human and animal viruses.

“The current pandemic highlights the need for effective antivirals to treat active infections, as well as vaccines, to prevent the infection,” said Professor Kin-Chow Chang who led the study. “Given that future pandemics are likely to be of animal origin, where animal to human (zoonotic) and reverse zoonotic (human to animal) spread take place, a new generation of antivirals, such as thapsigargin, could play a key role in the control and treatment of important viral infections in both humans and animals.”

“Although more testing is clearly needed, current findings strongly indicate that thapsigargin and its derivatives are promising antiviral treatments against COVID-19 and influenza virus, and have the potential to defend us against the next Disease X pandemic,” added Professor Chang.

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