Home News Willow Bark Extracts Have Broad-Spectrum Antiviral Effect: Study

Willow Bark Extracts Have Broad-Spectrum Antiviral Effect: Study

by Sean Martu

Recurring viral outbreaks have a significant negative impact on society. This creates a need to develop novel strategies to complement the existing antiviral approaches. In cell sample experiments, scientists from the University of Jyväskylä, the Natural Resources Institute Finland and the University of Turku investigated the antiviral potential of willow (Salix spp.) bark hot water extracts against coronaviruses and enteroviruses.

The emergence of viral outbreaks leading to epidemics and pandemics causes a huge strain on the global economy and public health.

Antiviral agents, such as vaccines, drugs, and virucides, help in reducing viral transmission.

Virucides are used to reduce the viral load on the surface and in the environment. They are used as disinfectants for surface sterilization of biological and medicinal products.

Additionally, they have been used to inactivate viruses in foodstuffs, detergents, and cosmetics.

However, the majority of the virucides are chemical disinfectants, which are hazardous in nature and cause environmental contamination. In addition, they cause side effects on human health, such as skin irritation.

Moreover, non-enveloped viruses like enteroviruses are largely resistant to chemical disinfectants.

Even though vaccines are an effective weapon against virus infection, it is not feasible to develop a vaccine against all the enteroviruses. In addition, the process of vaccine development and approval also takes time.

Currently, there are no clinically approved drugs for enteroviruses.

Thus, there is a great need to find broadly acting antiviral agents that would lower the infectivity of viruses around us and that could complement the vaccines and drugs in the combat against viruses.

“We need broadly acting and efficient tools to combat the virus load in our everyday life,” said Professor Varpu Marjomäki, a researcher at the University of Jyväskylä.

“Vaccinations are important, but they cannot deal with many of the newly emerging serotypes early enough to be effective on their own.”

In their previous study, Professor Marjomäki and colleagues showed that willow bark hot water extracts are highly effective against non-enveloped enteroviruses (Coxsackie virus A9) and not cytotoxic in the used concentrations.

Interestingly, none of the tested reference compounds, such as triandrin, salicin, salicylic acid, or picein, showed antiviral activities, suggesting that the bioactive properties of willow clone bark extracts could be due to the synergistic effects of different bioactive agents such as tannins and other polyphenols.

In the present study, willow bark hot water extracts were tested for their antiviral activity against HCoV-OC43 and SARS-CoV-2, and their mechanism of action was elucidated against the coronaviruses and for the previously tested enteroviruses.

“To make the extract, we harvested commercially grown willow branches,” the researchers said.

“The bark was cut into pieces, frozen, ground, and then extracted using hot water.”

The extracts tested by the team showed antiviral potency against both viruses by having a direct effect on the virus particles.

They caused clustering of both the viruses but halted infection in different ways for non-enveloped and enveloped viruses: through the increased stability of enteroviruses structure, but through the compromised structure of coronaviruses.

“The extracts acted through distinct mechanisms against different viruses,” Professor Marjomäki said.

“But the extracts were equally effective in inhibiting the enveloped as well as non-enveloped viruses.”

The authors also tested existing medical compounds derived from willow bark as well as commercially prepared salixin extract and salixin powder.

Of these, only the salixin extract showed antiviral activity, suggesting that the success of the scientists’ willow bark extract could result from the interactions of different bioactive compounds.

Further research will be needed to understand the bioactive compounds involved, their chemical structure, and how they work, potentially leading to revolutionary new antiviral treatments.

“We are presently continuing fractionations and bioactive molecule identification from willow bark extracts,” Professor Marjomäki said.

“This will give us a number of identified pure molecules which we can study in further detail.”

“Also, we will study a larger number of viruses with purified components. Purified components will give us better opportunities to study their mechanisms of action.”

The team’s results are published in the journal Frontiers in Microbiology.

Source: Sci-News


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1 comment

ZT June 17, 2024 - 6:38 am

Which subspecies of salix shows efficacy?


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