Essential oil from the dried and fresh leaves of Annona cacans (Anonnaceae): GC/MS analyses and anti-leishmanial potential

Annona cacans (Annonaceae) is known as “cortição” and the fruit is used as cathartic. In this study the chemical composition of essential oil from dried and fresh leaves of A. cacans and anti-leishmanial activity were evaluated. The leaves of A.cacans were separated into two batches of equal mass (266g), and the lot n°.1 was submitted to drying in an oven (25°C/12h) and lot n°.2 is formed by fresh leaves. The samples of lot n°.1 and 2 were submitted to essential oil extraction by hydrodistillation in a Clevenger apparatus. The chemical composition of the essential oils was determined by GC/MS. The anti-leishmanial activity against Leishmania infantum promastigotes was determined. The essential oils were incubated to the highest concentration of 150µg/mL for 24h at 24°C. Parasite viability was determined by MTT assay at 550nm. Pentamidine served as positive control and DMSO 0.5% as negative control. Each assay was performed in triplicate and the concentration necessary to 50% inhibitory concentration (IC₅₀) was calculated in µg/mL. Twenty compounds were identified in the essential oils of dried and fresh leaves. The germacrene B was the major constituent of both oils. The oils shows in vitro anti-leishmanial activity with IC₅₀=38.71 and 26.50µg/mL for essential oils of dried and fresh leaves, respectively. Further investigations are necessary to understand the possible mechanism of action in parasites as well as their systemic adverse effects, toxicity and efficacy toward a clinical employment.