Visceral leishmaniasis (VL) is part of a complex group of zoonotic parasitic infections capable of affecting humans and several species of wild and domestic animals. It is considered by the World Health Organization (WHO) as one of the most severe infections for humans, characterized by prolonged fever, weight loss, anemia, hepatosplenomegaly, and if untreated, can be fatal (Alvar et al., 2012).

In Brazil, VL is considered an important public health problem due to its high incidence, which affects poorer and more vulnerable populations. Caused by Leishmania infantum Nicolle 1908 and transmitted by the bite of the sand fly Lutzomyia longipalpis Lutz and Neiva 1912, VL represents an additional challenge for the public health system on the outskirts of large Brazilian cities, where low-income populations and precarious infrastructure are often concentrated and have ideal environmental conditions for vector proliferation (Brasil, Ministério da Saúde, 2016; Galvis-Ovallos et al., 2018).

In this scenario, it is essential to implement specific control and prevention strategies to combat this problem, with emphasis on vector control through the application of synthetic residual insecticides, such as the pyrethroids deltamethrin and α-cypermethrin (Costa, 2005; Brasil, Ministério da Saúde, 2016). However, it is important to highlight that the excessive and indiscriminate use of these conventional insecticides over time has contributed to developing resistance in sand flies (Alexander et al., 2009; Denlinger et al., 2015; Souza et al., 2016).

The growing inefficiency of these products has sparked interest in developing new alternatives. Plants emerge as a viable alternative due to the diversity of secondary metabolites with insecticidal potential, as many of these can cause damage to the nervous, digestive or respiratory systems of insects, interfere with vital physiological processes and affect feeding behavior, reproduction, growth and development (Isman, 2006; Miresmailli and Isman, 2014).

The Asteraceae botanical family has been extensively explored in terms of its chemical composition and biological activity (Verdi et al., 2005; Rolnik et al., 2021). Among numerous species that comprise this family, we highlight the Pseudobrickellia brasiliensis species (Spreng.) R.M. King and H. Rob., known as “arnica-do-campo”, native to Brazil and popularly used for presenting analgesic and anti-inflammatory functions (Athayde et al., 2019; Marinho et al., 2024). However, there are still no reports in the literature that attest to its insecticidal potential.

Therefore, the objective of the present study was to evaluate the toxicity of essential oil (EO) from P. brasiliensis leaves on adult sand flies of the species L. longipalpis under laboratory conditions and to chemically characterize this oil using gas chromatography coupled to mass spectrometry.