Avaliação da bioatividade de óleo essencial de Eugenia pyriformis sobre Lutzomyia longipalpis e Leishmania infantum

Abstract

Phlebotomine sandflies are vectors of Leishmania protozoa, posing a significant public health concern. Among the various sandfly species, Lutzomyia longipalpis stands out as the primary transmitter of L. infantum, the etiological agent of Visceral Leishmaniasis (VL), a zoonotic disease with high lethality if not treated early. The four main pillars of control involve health education, early diagnosis and treatment of human cases, control of the canine reservoir, and control of the vector, with the latter three posing significant challenges for health authorities. In this context, the use of botanical compounds has been widely studied, both for application as insecticides and parasiticides. Given the above, the objective of this study was to evaluate the bioactivity of the essential oil from Eugenia pyriformis leaves (OEEp) on vector insects. Additionally, the effect of OEEp on cultivated forms of Leishmania was assessed. OEEp was obtained through steam distillation from moist leaves of Eu. pyriformis collected in Perdões, Minas Gerais. Spectrometry identified β-Caryophyllene (28.21%), Caryophyllene oxide (12.79%), (+)- Spathulenol (6.58%), α-Copaene (5.73%), and β-Gurjunene (5.11%) as major compounds. OEEp was diluted in 4% (v/v) DMSO and used to prepare sugar solutions at concentrations of 2.5 mg/mL, 5 mg/mL, and 7.5 mg/mL, tested in survival, feeding, preference, and attraction assays, all with replicates and controls. To evaluate the leishmanicidal effect of OEEp, promastigotes and amastigotes of Leishmania infantum were used, with Miltefosine as a control. There was no significant difference between OEEp baits and sucrose (control) in survival, attraction, and preference assays. The results indicate that the tested concentrations of OEEp showed no significant differences compared to sucrose control in survival, feeding, attraction, and preference assays. However, when assessing the leishmanicidal potential of OEEp, a significant inhibition of the proliferation of L. infantum promastigotes and amastigotes was observed. Although OEEp did not demonstrate a direct insecticidal effect, its acceptance as a sugar bait by Lu. longipalpis paves the way for integrated strategies that combine bait attractiveness with its leishmanicidal potential.