A doctoral thesis from the University of Jyväskylä (Finland) investigated the effectiveness of plant-derived compounds against viruses that infect humans in her doctoral research. The study also examined whether antiviral properties could be added to materials by binding plant- and wood-derived compounds and extracts to them. The results offer new possibilities for antiviral solutions based on plant-derived ingredients in a wide range of everyday and healthcare applications.

Viruses that can cause severe diseases, spread efficiently, and rapidly adapt to changing conditions pose a major public health threat. A recent example is the COVID-19 pandemic caused by the SARS-CoV-2 coronavirus, which began in 2020. Although vaccines and antiviral medications exist for certain viruses, a large number of viruses still lack effective treatments. Therefore, new solutions are needed to reduce viral infectivity.

Tannic acid and resin acids render viruses nonfunctional

Doctoral Researcher Marjo Haapakoski demonstrated that tannic acid, a polyphenolic biomolecule found in plants, is effective against both enveloped coronaviruses and non-enveloped enteroviruses.

- I noticed that tannic acid prevented coronaviruses from entering cells and reduced also enterovirus attachment to cells. It also inhibited the uncoating of the enterovirus protein shell, thereby preventing the viral genome from entering the cells, says Doctoral Researcher Marjo Haapakoski from the University of Jyväskylä.

The study results demonstrated that resin acids found in conifer tree resin inhibit the infectivity of coronaviruses.

- To infect a cell, the lipid envelope of a coronavirus must fuse with a cellular membrane, such as that of a intracellular sorting organelle. The research demonstrated that resin acids act directly on the virus and block this fusion step, explains Haapakoski.

Antiviral properties can be added to surfaces

She also investigated the antiviral properties of textiles and cellulose-based materials coated with tannic acid or spruce bark extract. These coated materials displayed broad-spectrum antiviral activity. The effectiveness of tannic acid-coated cardboard was largely explained by the strong binding of enteroviruses to the material, and coronaviruses were also found to localize mainly in areas with high tannic acid content.

- The findings on the antiviral effects and mechanisms of plant-derived compounds and coated materials can be utilized in the development of future antiviral solutions, helping to reduce viral transmission risks in packaging materials, personal protective equipment, public spaces, and healthcare environments, specifies Haapakoski.

Marjo Haapakoski graduated with a Master of Science Degree from the Department of Biological and Environmental Science at the University of Jyväskylä in 2020, and she began her doctoral research in 2022. The supervisors of the study were Professor Varpu Marjomäki and Postdoctoral Researcher Mira Laajala. The research has been funded by the Research Council of Finland, Business Finland, and the Jane and Aatos Erkko Foundation.

Doctoral dissertation of MSc Marjo Haapakoski “Plant-Derived Antiviral Agents: Studies on Efficacy and Functionalization” will be publicly examined on Friday, 30 January 2026 at 12 o’clock noon. The opponent will be Professor Heli Harvala (University of Turku), and the custos will be Professor Varpu Marjomäki (University of Jyväskylä).