Scientists find natural compounds that hit COVID-19 from every angle

The research focused on Copaifera lucens because the team, led by Jairo Kenupp Bastos from the Ribeirão Preto School of Pharmaceutical Sciences at the University of São Paulo (FCFRP-USP), has long studied the chemistry and medicinal properties of plants in the Copaifera genus. Their prior experience helped guide the selection of this species for detailed investigation.

Galloylquinic acids are not new to science. Earlier studies have linked them to a range of biological effects, including antifungal and anticancer activity observed both in vitro and in vivo. They have also shown broad antiviral potential. In related research, similar compounds demonstrated strong inhibition of HIV-1 in laboratory and cell-based experiments, while producing lower toxicity compared to other tested substances.

Testing Safety and Antiviral Activity

With support from FAPESP, the researchers first isolated and characterized extracts from the leaves that were rich in galloylquinic acids. They then evaluated whether these compounds were safe for cells using cytotoxicity tests, an important step before assessing antiviral effects.

To measure how well the compounds could combat the virus, the team used plaque reduction assays. This method evaluates how effectively a substance can neutralize viral particles. The results showed clear activity against SARS-CoV-2.

The scientists also examined how the compounds interact with key parts of the virus. These included the receptor-binding domain of the spike protein, which enables the virus to enter human cells, as well as papain-like protease (PLpro), an enzyme that helps the virus evade immune defenses, and RNA polymerase, which is essential for viral replication. In addition, they analyzed the impact on viral protein production.

“This integrated approach allowed us to understand how the compounds work and how they act at the molecular level,” said Mohamed Abdelsalam, an assistant professor of pharmacognosy and natural product chemistry at the Faculty of Pharmacy at the Delta University of Science and Technology in Egypt. He is also affiliated with the School of Health Sciences at the Pompeu Fabra University TecnoCampus in Barcelona, Spain. Abdelsalam led the biological study jointly with Professor Lamiaa A. Al-Madboly, Head of the Department of Microbiology at the Faculty of Pharmacy at Tanta University in Egypt, and Associate Professor Rasha M. El-Morsi from the Department of Microbiology at the Faculty of Pharmacy at the Delta University of Science and Technology in Egypt. The study was conducted in collaboration with Egyptian researchers from Alexandria University.

Multi-Target Effects Against SARS-CoV-2

According to findings published in Scientific Reports, galloylquinic acids act on several stages of the viral life cycle. They can block the virus from entering cells, interfere with its replication process, and reduce the production of viral proteins. The compounds also appear to have anti-inflammatory and immunomodulatory properties, which may help regulate the body’s immune response, particularly in more severe cases of COVID-19.

“An important aspect revealed by this information is the multi-target mechanism of the compound, which reduces the likelihood of resistance developing. This is because many current antivirals act on only one viral protein, which promotes this effect,” says Bastos.

Next Steps and the Role of Biodiversity

Although the results are encouraging, additional research is required before these compounds can be developed into a treatment. Future steps include testing in living organisms and conducting clinical trials in humans.

The study highlights the value of exploring natural sources for new medicines. It also reinforces the importance of biodiversity, pointing to Brazilian plant life as a rich and strategic resource for discovering novel therapeutic compounds.