Potencial bioherbicida do óleo essencial de alfavaca visando o controle da dispersão do capim annoni

Abstract

The species Ocimum gratissimum L, popularly known as alfavaca, widely distributed in tropical and temperate regions, has important medicinal properties attributed to its volatile chemical constituents thymol and eugenol. In addition, they are used as flavorings in Amazonian cuisine, which have different flavors according to the variation in the content of their volatile components. Despite being a widely exploited species, studies of the bioherbicidal potential of this species are scarce. In this context, the essential oils (EOs) from the leaves of O. gratissimum, extracted via hydrodistillation, were characterized in terms of their chemical profile (via GC-MS), and submitted to bioherbicide tests (germination and seedling development test) against capim annoni, an important invader of pastures in the Pampas region. The EO of O. gratissimum was a potent inhibitor of the germination of capim annoni, being active at concentrations from 0.005% and reaching a reduction of almost 82% in germination when applied at a concentration of 0.1%. Following the observed effects on germination, the initial growth of capim annoni was significantly affected by concentrations above 0.05%. The chemical characterization study led to the identification of 8 volatile components, of which methyl eugenol and tetrapentacotane are the majority. These results, although initial, validate the efficiency of the essential oil as one of the promising biological products for the development of a bioherbicide. It is worth noting that the results presented in this Completion of Course Work (TCC) are part of a larger group of results associated with the project “Prospecting essential oils from Amazonian species for the control of annoni grass”, developed under the coordination of the researcher Dr. Joselia Maldaner in her Post-Doctoral internship under the supervision of Prof. Dr. Marilene Nunes Oliveira.