Development of Nanoemulsions to Enhance the Antileishmanial Activity of Copaifera paupera Oleoresins

Based on the ethnopharmacological evidences about the antileishmanial activity of Copaifera spp. oleoresins, the effects of crude extracts and fractions of oleoresin of two specimens from Copaifera paupera were evaluated on Leishmania amazonensis and Leishmania infantum strains. The oleoresin rich in α-copaene (38.8%) exhibited the best activity against L. amazonensis (IC(50) = 62.5 μg/mL) and against L. infantum (IC(50) = 65.9 μg/mL). The sesquiterpene α-copaene isolated was tested alone and exhibited high antileishmanial activity in vitro with IC(50) values for L. amazonensis and L. infantum of 17.2 and 11.4 μg/mL, respectively. In order to increase antileishmanial activity, nanoemulsions containing copaiba oleoresin and α-copaene were developed and assayed against L. amazonensis and L. infantum promastigotes. The nanoemulsion containing α-copaene (NANOCOPAEN) showed the best activity against both species, with IC(50) of 2.5 and 2.2 μg/mL, respectively. This is the first report about the antileishmanial activity of α-copaene.