|
Abstract
|
Abstract: Background: One of the most important causative agents of visceral leishmaniasis (VL)
is Leishmania infantum, which is mainly spread by Phlebotomus and Lutzomyia sandflies in the Old
and New World, respectively. Novel and e ective drugs to manage this neglected vector-borne
disease are urgently required. In this study, we evaluated the toxicity of carvacrol, thymol and
linalool, three common essential oil constituents, on amastigotes and promastigotes of L. infantum.
Methods: in vitro experiments were performed by 24 h MTT assay. Carvacrol, thymol and linalool at
concentrations ranging from 1.3 to 10 g/mL were tested on promastigotes of L. infantum. For in vivo
test, two groups of hamsters (Mesocricetus auratus) received 100 mg/kg of body weight/day of
carvacrol and thymol as intraperitoneal injection on day 7 post-infection, followed by a 48 h later
injection. The third group was treated with the glucantime as standard drug (500 mg/kg) and the
last group (control) just received normal saline. On the 16th day, the number of parasites and
histopathological changes in liver and spleen were investigated. Results: 24 h MTT assay showed
promising antileishmanial activity of thymol and carvacrol, with IC50 values of 7.2 (48 M) and
9.8 g/mL (65 M), respectively. Linalool at all concentrations did not a ect L. infantum promastigote
viability. In vivo toxicity data of carvacrol and thymol showed that the former at 100 mg/kg was the
safest and most e ective treatment with little side e ects on the liver. Conclusions: Overall, thymol and
carvacrol are highly promising candidates for the development of e ective and safe drugs in the fight
against VL.
|