Ação in vitro do óleo essencial de Lippia alba em culturas de promastigotas de Leishmania chagasi

Abstract

Leishmaniasis are zoonotic diseases caused by protozoa of the genus Leishmania spp., with a high global incidence. The visceral form are often highly lethal, and existing treatments rely on intravenous or intramuscular administration of drugs, which are associated with recurrence and significant contraindications. Notably, the plant Lippia alba has been previously described as an antiparasitic agent effective against both blood and tissue helminths (worms) and protozoa. Thus, this study aimed to evaluate the direct effect of Lippia alba essential oil on promastigotes of Leishmania chagasi. The oil was extracted via hydrodistillation and subsequently underwent chemotyping by gas chromatography and mass spectrometry. Simultaneously, L. chagasi promastigotes were maintained in axenic culture at 28ºC. The parasites were then incubated with different dilutions of the essential oil and treated with a resazurin-based developer solution for fluorescence measurement using a fluorimeter (550 nm excitation, 590 nm emission). Parasitic viability was determined based on the optical density values obtained. Chemotyping revealed that the L. alba sample used in this study belongs to the linalool chemotype. In vitro assays demonstrated that the inhibitory effect of the essential oil was most pronounced at the highest concentration tested (500µg/mL), achieving approximately 32% of the parasites. Thus, the essential oil of L. alba at high concentrations exhibited potential inhibitory activity against L. chagasi in vitro.