In vivo and in vitro effects of essential oils from Laureliopsis philippiana on Leishmania amazonensis

ARRIETA, VICTORIA J.; BRAVO, JESSICA; BRUNA FLAVIA ALEJANDRA; CARGNELUTTI DIEGO ESTEBAN; LOZANO, ESTEBAN S.

San Juan

Congreso; XLI Reunión Anual de la Sociedad de Biología de Cuyo; 2023

Sociedad de Biología de Cuyo

Leishmaniasis, a parasitic zoonotic disease, is on the rise in South America and has earned recognition as one of the neglected diseases by the World Health Organization. This is primarily because it disproportionately affects the low-income population with limited access to healthcare services. In Argentina, leishmaniasis is endemic in provinces such as Salta, Jujuy, Tucumán, Catamarca, Santiago del Estero, Chaco, Formosa, Misiones, and Corrientes. Leishmania amazonensis, one of the causative agents of this disease in our country, is notable for its capacity to induce a broad range of clinical symptoms, ranging from localized cutaneous leishmaniasis to severe forms characterized by mutilation, disability, and often poor response to treatment. Currently, there is no vaccine available for preventing leishmaniasis in humans, and the existing treatments, such as Glucantime, are unsatisfactory due to their high toxicity, cost, complex administration, and the emergence of drug-resistant strains. Consequently, it is imperative to explore innovative immunotherapeutic approaches based on the search for new compounds, screening molecules purified from plant resources. Essential oils (EOs) are combinations of terpenes that can be extracted from different parts of plants, including leaves, bark, roots, flowers, and fruits. Throughout history, EOs have been employed in traditional medicine for the management of a wide range of human ailments. Laureliopsis philippiana is a native tree widespread in the forest areas in the south of Chile and Argentina, known for its medicinal properties. Research has established that essential oils derived from L. philippiana exhibit insecticidal, antimicrobial, fungicidal and antitumoral properties. Therefore, the aim of the present work is to evalutate the possible antiparasitic effect/properties in vitro and in vivo of EOs from L. philippiana of Leishmania amazonensis. First, we evaluated the antiparasitic effect of all essential oils on L. amazonensis promastigotes. Paramela, Laurel, and Tepa exhibited significantly reduced parasite growth compared to the control group. Subsequently, we incorporated mice into our study as test subjects. Male BALB/c mice were infected in the right hind paw with 1x106 L. amazonensis promastigotes and treated with a formulation of Tepa+Vaselin 4%, that were administrated directly on the lesion one or three times a week. We worked with two groups: Tepa 1, which received one dose per week starting the following week after the infection commenced, and Tepa 2, which also received one dose per week but five weeks after the infection had started. We analysed different parameters like the swelling of the infection site, weight of the lesion, parasite load, splenic index and determination of the humoral immune response. We observed that Tepa treatment in both groups did not induce a significant alteration in swelling. However, during the final week of the protocol-measurement, Tepa 2 treatment exhibited a trend toward reducing swelling. Therefore, looking ahead, we intend to repeat the protocol with significant modifications.