New Amazonian plants with medicinal potential are at risk of extinction

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A potential microbial agent of plant origin. The property of reducing the accumulation of fat around the liver and fighting obesity and diabetes.

This is what recently discovered plants from the Brazilian Amazon can bring to medicine, in addition to being fundamental for biodiversity and ecosystem preservation. These properties, however, are threatened by the imminent risk of extinction.

The first species, named Aenigmanu alvareziaefound in the western Amazon, remained more than 50 years in a drawer in the botanical collection of the Field Museum in Chicago, until scientists were finally able to discover which group it belonged to.

The botanist and curator emeritus of the New York Botanical Garden, William Wayt Thomas, says that it all began in 1973, during an expedition by the Chicago museum to the Peruvian Amazon, in the region that today houses the Manu National Park, in Madre de Díos, led by ecologist Robert Foster.

Foster collected the plant’s fruits and leaves and, back at the museum, consulted experts, but they were unable to determine which group the plant belonged to, nor classify it as a new species. It was only with the advent of molecular biology that researchers were able to unravel their classification, published in the specialized scientific journal Taxon..

The mysterious plant or, as the genus says, “Manu’s enigma”, belongs to the Picramniacea family, composed of 53 species of small trees, with a neotropical distribution (in the Americas) and little known. The species name, “alvareziae”, is in honor of the biologist Patricia Álvarez-Loayza, who provided new specimens from which it was possible to extract genetic material for phylogenetic analysis.

Thomas is one of the only specialists in the group worldwide — the other is the Brazilian botanist and professor at the Institute of Biosciences at USP, José Rubens Pirani. “When I saw the plant for the first time, I didn’t even think that it was a picramniaceae, because the leaves are very different, they are unique (simple), while in the other species of the group they are divided (composite)”, said the American botanist in interview to sheet in October.

In the article, the researchers describe four areas where the species occurs: three in northern Peru, in an area where the Madeira River flows, and an area close to the municipality of Cruzeiro do Sul, in Acre.

One of the difficulties of studying this and other species of the group is its cryptic feature — the flowers are tiny and, as the trees are not so tall, it is difficult to see them in the forest. “As the flowers are very small, studying using traditional techniques, such as morphology, is limited, so DNA analysis was crucial,” explained Pirani, who was one of the reviewers of the article.

He explains that organisms with reduced distribution areas, such as the species of the group, are more susceptible to extinction due to changes in the environment. “Although habitat destruction in general affects all organisms, for those that have smaller populations, or are rarer, the risk of disappearance is greater,” he said, adding that the restricted area of a. alvarezaeespecially in Brazil, can put the species at risk.

It is the same phenomenon that threatens another recently described Amazon plant that already has two populations at risk of disappearing. the species cornuta tovomitefrom the Clusiacea family, occurs in four areas that suffer from environmental pressures in the state of Amazonas, according to the ecologist at Inpa (National Institute for Research in the Amazon) and first author of the study, Layon Oreste Demarchi.

Demarchi carried out monthly campaigns in areas of the Uatumã sustainable use reserve, in the municipality of São Sebastião do Uatumã (AM), and managed to collect several specimens of the plant with flowers and fruits, essential for taxonomic studies. “I then compared it with other specimens from the Inpa herbarium and other digitized collections, in addition to asking for help from study co-author Lucas Marinho, a specialist in the genus, who said that it was probably a new species”, he reports.

As the species occurs in the so-called campinaranas, which are distinct areas in the middle of the Amazon forest, similar to a restinga forest, with very poor nutrient and sandy soil, the illegal extraction of sand in two areas of distribution of the plant close to the municipality of Manaus probably already led to the disappearance of the species at the site.

“Because they are areas subject to a different climatic condition, the species found there evolved specialized adaptations to this type of environment, being often endemic [só ocorrem ali]. Because of this context and because only four populations are known, it can already be considered at risk of extinction”, adds the ecologist.

And what are the relationships with the pharmacological potential of the species? The plants of the Picramniacea family, especially the genus picramnia, have known medicinal uses, although they are still linked to traditional use, and are not yet used in the production of medicines. In animal tests in the laboratory, positive results were found in the reduction of fat around the liver, with potential use for the prevention of obesity linked to metabolic diseases.

already the tovomite has microbial properties. The findings, in both cases, took years before they were formally presented to science. Research of this type shows the importance of continuous investment in basic research, which seeks to understand issues related to the origin and relationships of organisms in nature.

“I was lucky to have continuous investment, otherwise I wouldn’t have been able to do the [trabalho de] field and find so many specimens”, explains Demarchi. “At this point I need to thank CNPq and Inpa, but unfortunately, with the recent cuts in science in the country, I know that research like this will be increasingly difficult”, he says.

In the case of Thomas, the binational Flora Amazônica project, a partnership between Inpa and the NY Botanical Garden, provided more than 25 expeditions in the largest Brazilian forest for eight years between 1980 and 1990, with the collection of almost 33,000 specimens. “It is known that tropical forests are very diverse, but the only way to find out is by investigating, going to the field to collect and then describing the species found and their areas of occurrence. Such data are fundamental for conservation”, he adds.

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