Ancient Herbal Compound Halts Fish Virus in Lab and Nature

Jim Crocker
8th March, 2024

Ancient Herbal Compound Halts Fish Virus in Lab and Nature

Image Source: Natural Science News, 2024

Key Findings

  • Bufalin, a Chinese medicine compound, effectively fights a fish virus (IHNV) in salmon and trout
  • The compound blocks the virus early, preventing it from attaching and replicating in cells
  • Treated fish had higher survival rates, showing bufalin's potential as an antiviral in aquaculture
In the aquaculture industry, infectious diseases can wreak havoc, causing significant economic losses and impacting global food security. One such disease is infectious hematopoietic necrosis (IHN), which affects salmon and trout populations. The virus responsible for IHN, known as Infectious hematopoietic necrosis virus (IHNV), leads to high mortality rates in fish farms. Despite the availability of a DNA vaccine, concerns over biosafety have driven scientists to search for alternative treatments. Researchers from the Chinese Academy of Fishery Sciences[1] have made a promising discovery in this regard, finding that bufalin, a compound traditionally used in Chinese medicine, could be an effective antiviral agent against IHNV. Bufalin is not entirely new to the scientific community. It is one of the cardiac glycosides, a group of naturally occurring compounds used to treat heart conditions. These compounds have been of interest for their potential therapeutic uses beyond cardiology, including anticancer[2] and antiviral applications. Notably, bufalin has previously demonstrated potent activity against various coronaviruses[3], suggesting its broad antiviral potential. The study involved screening 1,483 compounds from a traditional Chinese medicine library to identify those with potential antiviral activity against IHNV. Bufalin stood out, showing the ability to significantly inhibit the virus at concentrations that were not toxic to host cells. The researchers found that the effective concentration needed to inhibit the virus by 50% (IC50) was 0.1223 µM, while the concentration at which the compound becomes toxic to cells (CC50) was greater than 20 µM. This indicates a high selectivity of bufalin for the virus over the host cells. The antiviral action of bufalin was observed during the early stages of the viral life cycle. It blocked the attachment of the virus to the host cell and the replication of viral RNA, which is a crucial step in the production of new viruses. However, bufalin did not affect the internalization of the virus—once the virus was within the cell, bufalin's effects were not observed. In addition to in vitro results, bufalin was tested in vivo using rainbow trout, a common host for IHNV. The treated fish showed a significant increase in survival compared to those treated with a mock drug. Monitoring of viral loads in these fish confirmed the antiviral activity of bufalin. The mechanism of action of bufalin appears to involve the sodium/potassium pump (Na+/K+-ATPase), a protein that regulates the balance of sodium and potassium ions in cells. The antiviral activity of bufalin was dependent on the concentration of these ions, indicating that the compound may exert its effects by targeting this pump. This is consistent with earlier findings that cardiac glycosides, including bufalin, modulate this pump and can activate cell signaling pathways that impair viral infection[4]. While bufalin's potential is clear, it's important to note that the compound also has a history of toxicity, particularly at high doses[3]. However, the concentrations effective against IHNV are well below the toxic threshold, suggesting a window of safety for its use as an antiviral agent in aquaculture. The discovery of bufalin's antiviral properties against IHNV is a significant step forward in the fight against IHN. It provides a promising alternative to the existing DNA vaccine and opens the door to further research and development of bufalin-based treatments. As the aquaculture industry continues to grow, such advancements are critical to ensuring the health of fish populations and the sustainability of global food resources.

MedicineBiotechMarine Biology

References

Main Study

1) Traditional Chinese medicine bufalin inhibits infectious hematopoietic necrosis virus infection in vitro and in vivo.

Published 5th March, 2024

https://doi.org/10.1128/spectrum.05016-22

Related Studies

2) Cardiac Glycosides as Autophagy Modulators.

https://doi.org/10.3390/cells10123341

3) Broad Spectrum Antiviral Properties of Cardiotonic Steroids Used as Potential Therapeutics for Emerging Coronavirus Infections.

https://doi.org/10.3390/pharmaceutics13111839

4) Na+/K+-ATPase as a Target of Cardiac Glycosides for the Treatment of SARS-CoV-2 Infection.

https://doi.org/10.3389/fphar.2021.624704


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