A rainforest on Brazil’s east coast has turned up a possible new weapon against covid-19.
An international team of biologists, immunologists and pharmaceutical chemists found that leaves of Copaifera lucens Dwyer, a tree endemic to the Mata Atlantica, contain compounds that can neutralise covid-19 through a “multitarget mode of action”, according to the team’s new study.
The compounds are extracts from the plant called galloylquinic acids.
“Many current antivirals act on only one viral protein,” pharmacist Jairo Kenupp Bastos said in a statement. Bastos is a professor at the Ribeirão Preto School of Pharmaceutical Sciences at the University of São Paulo and coordinated the project.
“An important aspect revealed by this information is the multi-target mechanism of the compound, which reduces the likelihood of resistance developing,” Bastos said.
The study said the galloylquinic acids are a subset of tannins. Researchers identified six subcategories of galloylquinic acid in the plant using ultraviolet spectroscopy methods after distilling the chemicals from dried, pulverised and specially treated leaf samples.
According to the study, one molecular configuration, 3,4,5-tri-galloylquinic acid, showed a “strong binding affinity” with the receptor binding domains of covid-19’s spike protein.
Further tests, including plaque reduction neutralization assays, showed that safe concentrations of galloylquinic acid also bound to and neutralised covid’s papain-like protease enzyme and RNA polymerase, an enzyme essential to viral replication.
“This integrated approach allowed us to understand how the compounds work and how they act at the molecular level,” study coauthor Mohamed Abdelsalam said in a statement. Abdelsalam is an assistant professor with the Delta University of Science and Technology in Egypt.
The source text also said the galloylquinic acids found in Copaifera lucens appear to inhibit HIV-1, along with other antiviral and antifungal properties that helped inspire the research.
The findings come from a country the United Nations classifies as the leading “mega-biodiverse” nation, “unmatched by any other”. Nearly a quarter of all plant species on Earth, about 55,000 species by some estimates, are found in Brazil.
Brazil’s President Luiz Inácio Lula da Silva won re-election in 2022 after promising net “zero deforestation” across the country. Data from Global Forest Watch showed deforestation in the Brazilian Amazon fell by 36 percent during his first year back in office.
The São Paulo Research Foundation, which helped fund the study, said more work is needed before any drug could be developed.
“A few more steps remain before the substance can be developed into a drug against covid-19, including in vivo and clinical trials,” the foundation noted. “However, the study … also reinforces the idea that Brazilian flora is a rich and strategic source for discovering new drugs.”
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