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Sowing Seeds Through Plant Taxonomy

CREDIT: Célia Cabral

Originally trained as a plant taxonomist, Célia Cabral likes to name and classify. "It is fundamental to have a strong knowledge in botany for any work with plants; we have to be sure about identification," the Portuguese researcher says. But Cabral, 31, is a difficult scientist to categorize. A postdoc at the University of Coimbra, Cabral took a multidisciplinary approach to taxonomy that has led her into the study of plants' medicinal properties. "I love so many different aspects of plants," she says.

"She also had to quickly learn many new techniques and jump from lab to lab to accomplish her objectives." -- Helena Freitas.

In one of her most recent projects, Cabral is using her knowledge of plants to sow seeds for the future, for her own and her country's prosperity, co-founding a company that produces essential oils. One of her Ph.D. supervisors believes the project suits her. "I think this is a very positive development in Célia's career all around and something Célia will do well in. It suits her independent spirit," says Michael Möller, a researcher at the Royal Botanic Garden Edinburgh in the United Kingdom.

Strong roots

As a child, Cabral loved reading books and watching documentaries about science, and she enjoyed "identifying plants, even those that grow along the streets," she recalls. In high school, she discovered that she enjoyed "testing new things" in lab experiments, she says.

Cabral entered a 5-year degree program in biology at the University of Coimbra in 1997, intending to pursue a career developing new medicines. But in her second year, she became fascinated with the taxonomical classification of plants and botanical nomenclature. For her final-year project, she studied the taxonomy, ecology, and biogeography of a genus of grass called Melica under the supervision of Fátima Sales.

That was followed by a 1-year postgraduate program in forest resources and sustainable development, during which she studied plant interactions, biodiversity, geographical systems, and economics. Her foundation in biology "was the best way" to start her multidisciplinary career, she says. It gave her "a very good background in ... all those important and fundamental things."


In 2003, Cabral started a Ph.D. with Sales, her first-degree adviser, on Vitex L. (Vitex for short), a genus of flowering shrubs and trees that grow mainly in tropical areas. Vitex is "a wonderful and enigmatic genus" whose phylogeny is "still not fully resolved," Cabral says.

The Vitex genus includes some 250 species. Cabral decided to focus on a group of 26 African species whose most recent taxonomic description dated back to the late 1920s. She revised the classification of all 26 species by researching collections in her university's herbarium and other places including the Royal Botanic Gardens, Kew, in the United Kingdom, the French Natural History Museum in Paris, and the National Botanic Garden of Belgium in Meise.

Cabral supplemented the traditional approach to taxonomy with several other disciplines. "She also had to quickly learn many new techniques, and jump from lab to lab to accomplish her objectives," Helena Freitas, the director of the University of Coimbra's Botanical Garden, writes in an e-mail to Science Careers.

Cabral spent more than a year and a half at the Royal Botanic Garden Edinburgh, studying the molecular phylogeny of Vitex and its historical geographical dispersion with Möller. "A challenge was the extraction of DNA from herbarium material," Möller writes in an e-mail. "Her data demonstrated that the Vitex lineage includes several other genera previously treated separately from Vitex. This has fundamental taxonomic consequences," Moeller says. "Her work also showed interesting geographic patterns of transatlantic dispersals from Africa to South America."

Cabral worked on the chemical characterization of the essential oils of her Vitex species under the supervision of Lígia Salgueiro, the coordinator of the Bromatology, Pharmacognosy, and Analytical Sciences Group at Coimbra University's Faculty of Pharmacy. "Her Ph.D. project involved plants very difficult to access. ... This was a big challenge" that she overcame with her determination, Salgueiro writes in an e-mail. Cabral extracted essential oils through hydrodistillation in Cameroon during a 1-month expedition in collaboration with the University of Yaoundé 1 and the Royal Botanic Gardens, Kew.

Back in Coimbra, she chemically analyzed the oils, finding her Vitex African group contained a high level of sesquiterpene hydrocarbons and possessed antifungal activity. For those plants that proved too hard to get, she went to what is now the Institute of Applied Botany and Pharmacognosy in Vienna to use a technique that made it possible to screen the chemical composition of essential oils from dried herbarium material.

Plant validation

Cabral found out she was pregnant the day she submitted her thesis. She gave birth to her son 2 months after her viva in September 2008. For the first year of the child's life, she split her working time between home, where she wrote papers and grant applications, and the university's herbarium, where she restored historical plant specimens. She got some help from her mother, who sometimes still comes to stay from her home some 100 kilometers away.

Cabral resumed her research at the end of 2009 with a project spanning taxonomy and pharmacognosy -- the study of natural medicines. But a few chaotic months ensued for Cabral as an incident with her child's father, who had started working at the herbarium shortly after they met, "affected my research and career," she says. She split up with her child's father and quit the herbarium to work full-time at the faculty of pharmacy. "It was difficult," Cabral says, but "now I am publishing and developing much quicker."

CREDIT: Célia Cabral
Célia Cabral in the lab.

She worked on validating the use of traditional medicinal plants found in the Parque Natural da Serra da Estrela, such as juniper. "Data from traditional medicine and ethnopharmacological studies [are] very important ... because they indicate the most promising plants with medicinal properties, which parts of the plant, how to prepare the extracts," Cabral says. She chemically tested plant extracts for their antioxidant, antifungal, and anti-inflammatory properties. A postgraduate course on health products based on plants helped her fill in the blanks in chemistry and cell biology, she says.

Today, Cabral studies the Portuguese history of pharmacognosy. Her first task is to identify species in the faculty's medicinal plants collection: Many of the glass containers "are not identified, with the labels completely destroyed, [or] with just a file out somewhere," Cabral says. She will then organize an exhibition for the public with a historical review of Coimbra's research on medicinal plant products like quinine.

Jardins de Vapor

Last April, Cabral co-founded a company called 'Jardins de Vapor' to distill essential oils from Portuguese aromatic plants. The idea had been brewing for quite some time: In 2005, on a visit to Budapest to attend the International Symposium on Essential Oils, she was struck by Hungary's distilleries and "huge fields" of fennel and chamomile, Cabral says. There is a "lack of essential oils production in Portugal," Salgueiro says. "Usually costumers have to import the essentials oils from other countries." Cabral reasoned that, in Portugal, "We have lots of sun, very good conditions to produce aromatic plants," she says. "So why not produce our plants and distill them here?"

It took some time for Cabral to find what she needed most to implement her idea. In the faculty of pharmacy, she met her two associates -- Ph.D. student Gustavo Costa and technician Tânia Santos Carvalhais. Cabral "is always very sure of herself and knows how to develop a solid idea and concept," Costa writes in an e-mail. In the faculty, she also found a distiller designed years ago by a former lab director that was smaller but similar to the ones she saw in Hungary. The three scientists then applied for support to the Portuguese incubator Pedro Nunes, which helped them get established at the site of another incubator 40 kilometers away from Coimbra.

So far, the three co-founders have been focusing on trying to locate farms, determining the best distilling conditions for each plant species, and analyzing the essential oils' composition. Cabral has "already showed me that she has the know-how and experience needed," Costa says. The marketing aspects have been going smoothly thanks to significant media attention. By now, the company has a product catalog of 17 plant species, including lavender, eucalyptus, and rosemary, which they sell mainly to Portuguese spas. As scientists, "We only mention some uses for the oils that are scientifically validated and published," Cabral says.

"I am sure Celia's company will develop and prosper. She has the right mind and mindset to move any company forward," Möller says. "We have to work a lot, but I hope to have a good result with the enterprise," Cabral says, and not only for herself. Cabral hopes the initiative will encourage other people in Portugal to "develop all these things that can be developed, not just complaining about the economy."

Elisabeth Pain is Contributing Editor for Europe.

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