The team have reviewed up to 2,000 year-old written sources from ancient Greece, but also from traditional Chinese and European medicine and works of folk medicine in a search for typical symptoms. In 160 cases, they were able to establish an unequivocal connection between the reported healing effect and a given plant, fungus, lichen or moss and collect the biological material. The team then recorded the candidates in a database and produced extracts for each of them, which in turn may contain hundreds of chemical compounds.
Scientific analysis of natural extracts
With the Jena University Hospital, the natural extracts were pitted against various viruses that make their home in the respiratory system. The team observed how well the respective herbal substances could protect the infected lung epithelial cells from damage - in the test tube setting.
The best 28 candidates were then placed in Petri dishes on cell cultures infected with respiratory pathogens, including drug-resistant strains of influenza virus. Their antiviral potential was compared with a known neuraminidase inhibitor drug to which some pathogens are already resistant. Neuraminidase inhibitor drugs should act by blocking the viral surface protein so that viruses that have already reproduced in the host cell cannot spread. “Once an extract proves to be active, we start a laborious phytochemical analysis. We investigate the composition and then isolate specific antiviral active compounds,” says Judith Rollinger.
Beating viral drug resistance
Combining this work with other approaches including chemoinformatics the researchers identified possible new neuraminidase inhibitors that may defeat the drug-resistance. In collaboration with chemoinformatics experts from the Universities of Innsbruck and Hamburg, they modelled the 3D structure of the neuraminidase binding site and predicted compounds that could bind there and block the site. Judith Rollinger considers it a particularly successful outcome that the team was able to identify natural substances with dual effects in the course of the FWF-funded project.
Mulberry inhibits both viral and bacterial neurimidase
These substances inhibit two pathogens responsible for lung infections: influenza viruses and pneumococci (Streptococcus pneumoniae). Ingredients from the root bark of the mulberry tree (Morus alba) inhibit both viral and bacterial neuraminidase. In a follow-up project funded by the Swiss Doerenkamp Foundation, clinical research will be continued on the most promising candidates. In a follow-up project in Vienna, the group now hopes to make the leap to the coronavirus. Like the influenza virus, coronavirus attacks the lungs severely and, given the ongoing pandemic, it is currently the focus of international research groups worldwide.
A bacterium, virus, or other microorganism that can cause disease.Full medical glossary