Hidden Antivirals Discovered in Plant Supplement

Trace compounds, not main ingredient isoquercitrin, found to have potent effects against Ebola, Zika, and SARS-CoV-2 in lab tests.

Apr. 13, 2026 at 2:40pm

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A bold, abstract painting in muted greens, browns, and blues depicting the complex molecular structure of the newly discovered dicitrioside antiviral compounds, visualized through sweeping geometric arcs, concentric circular patterns, and precise botanical spirals, conveying the intricate natural order of these potent medicinal molecules.The discovery of rare, potent antiviral compounds hidden within a common plant supplement underscores the value of closely examining natural products for their medicinal potential.Chicago Today

Researchers have uncovered a new family of antiviral compounds called dicitriosides hidden within samples of the plant-derived supplement isoquercitrin. While isoquercitrin itself showed no antiviral activity, the dicitriosides present in lower concentrations demonstrated potent inhibition of highly transmissible viruses like Ebola, Zika, and SARS-CoV-2 in cell-based experiments.

Why it matters

This discovery highlights the importance of examining minor components in natural products, as the true medicinal effects may lie in trace compounds rather than the main marketed ingredient. The dicitriosides' high antiviral potency at low concentrations makes them promising drug candidates against emerging viral threats.

The details

After finding that a 90% pure isoquercitrin sample had strong antiviral effects, but a 98% pure sample did not, researchers at the University of Illinois Chicago and Montreal Clinical Research Institute used separation techniques to isolate the true antiviral compounds. They discovered a new family of molecules called dicitriosides - triterpenoids with two cinnamate chains and a branched sugar chain. In cell tests, the dicitriosides showed 25 times higher antiviral potency against SARS-CoV-2 compared to the original 90% pure isoquercitrin mixture.

  • In 2022, biochemist Majambu Mbikay contacted natural products expert Guido Pauli about the antiviral properties of an isoquercitrin sample.
  • Over the next 2.5 years, the researchers used separation techniques to isolate the true antiviral compounds from the isoquercitrin mixture.
  • The dicitriosides were found to make up less than 1% of the original 90% pure isoquercitrin sample.

The players

Guido Pauli

A natural products expert at the Pharmacognosy Institute at the University of Illinois Chicago.

Majambu Mbikay

A biochemist at the Montreal Clinical Research Institute.

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What they’re saying

“There are as many different 'isoquercitrins' as there are biological effects.”

— Guido Pauli, Natural products expert

“Everybody looks at the elephant in the room. We're looking at the mouse in the room.”

— Guido Pauli, Natural products expert

What’s next

The research teams are now working to identify which plants produce the rare dicitrioside compounds and determine the key structural features responsible for their antiviral activity.

The takeaway

This study demonstrates the value of closely examining minor components in natural products, as the true medicinal benefits may lie in trace compounds rather than the main marketed ingredient. The discovery of the potent antiviral dicitriosides highlights the potential for uncovering novel drug candidates from plant-derived supplements.