Essential Oil of Pilocarpus Microphyllus Stapf. Against Promastigotes Forms of Leishmania Infantum

Abstract

Leishmaniasis makes up a group of infectious diseases caused by different species of the genus Leishmania. The visceral form as reponsible for the hight number of deaths. The treatment is still quite limited by some factors such as long duration, adverse effects, toxicity, high costs, which reinforces the importance of the discovery of new drugs for the disease. Pilocarpus microphyllus Stapf. popularly known as Jaborandi, is used for various medicinal purposes. Its leaves contain important imidazole alkaloids; some with functions already well known. The objective of this work was to evaluate the antileishmania activity of the essential oil of Pilocarpus microphyllus Stapf. against promastigotes forms of Leishmania infantum . Promastigotes forms L. infantum in log phase of growth were plated in the amount of 1x10 6 per well, in a 96-well plate containing essential oil obtained from the leaves of Pilocarpus microphyllus in eight serial dilutions, at concentrations of 800 to 6.25 μg/mL. The plate was then incubated in (BOD) oven at 26°C for 48 hours, remaining 6 hours 20 μL Resazurin 10 mol/L per well was added. At the end, the plate reading was performed on plate reader at 550 nm. The minimum concentration (IC50) was obtained by calculating probit regression. The essential oil of P . microphyllus Stapf. demonstrated activity on promastigote forms of L. infantum , with activity dependent on concentration, presented an IC50 of 6.343 μg/mL. In the literature some activities of the constituents of P . microphyllus are already reported. The essential oil of P. Microphyllus Stapf. was shown to be very promising against promastigote forms of L. infantum . Future studies will be conducted to investigate their cytotoxicity on host cells, elucidate their mechanism of action, and evaluate their in vivo activity in the treatment of disease in experimental models.