Using plants to fight Ebola and COVID-19

By UdeMnouvelles Apr 30th, 2026

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In 5 seconds In the lab, scientists at the IRCM have discovered new and promising antiretrovirals in two previously unknown compounds of a plant extract rich in the common flavonoid isoquercitrin.

The discovery illustrates how compounds present in vanishingly small amounts in nature can have major therapeutic potential.
Photo : Getty

Scientists at the Université de Montréal's affiliated Montreal Clinical Research Institute (IRCM) have identified a new family of natural molecules with strong antiviral activity, notably against the Ebola virus and SARS‑CoV‑2, the virus responsible for COVID‑19.

The discovery comes at a time of renewed fears of the rapid emergence of new pandemics, and highlights the ongoing search at the IRCM for novel antiviral agents derived from natural sources.

Led by UdeM emeritus medical professor Michel Chrétien and Majambu Mbikay of the IRCM’s functional endoproteolysis laboratory, the development is detailed in a study published in the American Chemical Society (ACS)'s Journal of Natural Products.

As early as 2016, and again in 2020, IRCM researchers demonstrated that a plant extract rich in isoquercitrin—a flavonoid found in many plants—exhibited strong antiviral activity in the laboratory.

One critical question, however, remained: was this effect truly due to isoquercitrin itself, or to compounds present in very small amounts within the extract?

To resolve this puzzle, Mbikay and his research assistant Annie Roy went looking for the proverbial “needle in the haystack,” an effort that required nearly 30 months of intensive research.

For help, they brought in Guido F. Pauli, a chemist and leading expert in natural products at the University of Illinois Chicago, and Logan Banadyga, director of the Department of Molecular Virology at Canada’s National Microbiology Laboratory, in Winnipeg.

Michel Chrétien, professor emeritus at the Faculty of Medicine of Université de Montréal
Photo : Amélie Philibert, Université de Montréal

Two rare but highly potent molecules

Using advanced analytical methods and a rigorous, bioassay‑guided approach, the research team demonstrated that the antiviral activity did not originate from isoquercitrin itself, but rather from two previously unknown triterpenoid compounds.

Though present at only 0.4 per cent of the analyzed extract, these newly identified molecules, named dicitriosides, proved to be up to 25 times more active than the original extract against Ebola virus and SARS‑CoV‑2 under experimental conditions.

As such, they illustrated the efficacy at pharmacologically achievable concentrations.

“This discovery illustrates how compounds present in vanishingly small amounts in nature can have major therapeutic potential,” said Mbikay. “It also underscores the importance of carefully examining the true composition of natural products used in biomedical research.”

“Although this work is still at the preclinical stage, it opens promising avenues for the discovery of new broad‑spectrum antivirals derived from natural products,” the scientists state in their study.

“No one knows when the next pandemic will occur, but one thing is certain: we must be prepared,” added Chrétien.

“These results demonstrate the importance of long‑term fundamental research and international collaboration in anticipating the public-health challenges of the future.”

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