A tree with antimicrobial properties

Croton urucurana, popularly known by names such as “Sangre de Drago”, is a tree that reaches between 4 and 10 meters in height and about 40 centimeters in trunk diameter. It is common to find it in waterways in some areas of Argentina. It is also present in areas of Paraguay, Brazil and Uruguay, basically as a cultivated species.

When incisions are made in the bark of this tree, it exudes a reddish latex, hence acquiring its popular name. This latex has applications in popular medicine for the treatment of wounds and skin ulcers, with antibacterial and antifungal properties. Its use is very common in the ethnomedicine of Peru, Ecuador and Colombia, where it is purchased in markets, craft fairs and health food stores.

Curiously, the usefulness of this latex has been absent in the records of the Argentine National Pharmacopeia. Croton urucurana is the only native species of the Euphorbiaceae family, which has Croton lechleri ​​as its main exponent, with similar medicinal qualities.

Because plant species can vary their chemical composition according to the characteristics of the soil and climate of different regions (pedagoclimatological influences), and given that there is no scientific information available on the activity of C. urucurana extracts from the northeast region of Argentina, the research proposal has emerged by the biochemistry student from the National University of the Northeast (UNNE) in Argentina, Moira Soledad Ríos Müller, who accessed a Scholarship to Stimulate Scientific Vocations (EVC-CIN Scholarships ).

In it, the objective was to study the activity of the different organs of C. urucurana from the Argentine province of Corrientes, to verify if the native specimens have properties comparable to those of other regions and thus be able to validate their ethnomedicinal use.

The scholarship project is called “Antimicrobial activity of Croton urucurana ‘sangre de drago’ and is directed by Dr. Ana María Torres and co-directed by the biochemist Specialist María Susana Scaramellini Burgos, both from the Professor Armando Ricciardi Natural Products Laboratory, belonging to the dual dependency institute IQUIBA-NEA-UNNE-CONICET.

This research proposes to protocolize the methodology to obtain and preserve essential oils and bioactive extracts from the different organs of C. urucurana (dragon’s blood), in such a way as to ensure the chemical composition and quality of the extract to achieve a long-term product. standardized. On the other hand, the properties attributed to this species as antimicrobial will be verified using in vitro techniques.

From left to right: Ana María Torres, Moira Soledad Ríos Müller and María Susana Scaramellini Burgos. (Photo: National University of the Northeast / Argentina Investiga)

Why is this study on the antibacterial properties of this plant species important?

Antimicrobial drug resistance, according to the WHO, is one of the top ten threats to global public health. The misuse and excessive use of antimicrobial drugs is the main factor that determines the emergence of drug-resistant pathogens. Lack of access to quality antimicrobial medicines and shortages of antibiotics affect countries at all levels of development.

Antibiotics are increasingly ineffective due to drug resistance due to inappropriate use. This leads to more difficult-to-treat infections and increased mortality. The new study is in line with the search for new antibacterials.

Is it reliable to develop antibacterials from plant extracts and oils?

According to the WHO, 75% of the population depends almost exclusively on plants for health care. The biodiversity and ancestral knowledge transmitted by indigenous peoples places Argentina in a privileged place for the development of phytotherapeutics, with phytotherapeutic medicines being understood as those that are obtained through an appropriate technological process, in which only medicinal plants such as raw material.

The scientific contribution in this line of development is to standardize the final product ensuring purity, percentage of active ingredients and biological effects. Ríos Müller will work on some of these aspects, that is, discovering this potential, preserving biodiversity, and safeguarding knowledge for traditional use.

Regarding the methodology, the C. urucurana samples will have the corresponding botanical identification and deposit in the CTES herbarium of the Institute of Botany of the Northeast (IBONE). Subsequently, the plant material will be separated into various active organs such as leaves (as pruning to preserve the biodiversity of native natural resources); bark and latex, through incisions in the trunk of specimens more than 20 centimeters in diameter.

Obtaining the extracts – already in the laboratory – will be carried out by maceration in different solvents, which will yield dry extracts that will be preserved in a desiccator. The essential oils of leaves and bark will be separated by dragging with water vapor.

The extracts and essential oils will be screened for antimicrobial activity, that is, their ability to act against microorganisms, determining important quantitative parameters, such as minimum inhibitory and bactericidal concentrations. The principles responsible for said activity will be isolated and identified.

It is important to mention that the project complies with all ethical and environmental rules for the preservation of human and animal life, and does not contemplate technologies that could compromise the environment. (Source: Juan Monzón Gramajo / National University of the Northeast / Argentina Investiga)