Endlicheria bracteolata (Meisn.) Essential Oil as a Weapon Against Leishmania amazonensis: In Vitro Assay

The difficulties encountered and the numerous side effects present in the treatment of cutaneous leishmaniasis have encouraged the research for new compounds that can complement or replace existing treatment. The growing scientific interest in the study of plants, which are already used in folk remedies, has led our group to test Endlicheria bracteolata essential oil against Leishmania amazonensis. Several species of the Lauraceae family, or their compounds, have relevant antiprotozoal activities Therefore, the biological potential on L. amazonensis forms from the essential oil of Endlicheria bracteolata leaves was verified for the first time in that work. The antileishmanial activity was evaluated against promastigotes and intracellular amastigotes, and cytotoxicity were performed with J774.G8, which were incubated with different concentrations of E. bracteolata essential oil. Transmission electron microscopy and flow cytometry were performed with E. bracteolata essential oil IC(50). Promastigote forms showed E. bracteolata essential oil IC(50) of 7.945 ± 1.285 µg/mL (24 h) and 6.186 ± 1.226 µg/mL (48 h), while for intracellular amastigote forms it was 3.546 ± 1.184 µg/mL (24 h). The CC(50) was 15.14 ± 0.090 µg/mL showing that E. bracteolata essential oil is less toxic to macrophages than to parasites. Transmission electron microscopy showed that E. bracteolata essential oil treatment is capable of inducing mitochondrial damage to promastigote and intracellular amastigote forms, while flow cytometry showed ΔѰm disruption in treated parasites. These results could bring about new possibilities to develop products based on E. bracteolata essential oil to treat cutaneous leishmaniasis, especially for people who cannot receive the conventional therapy.