With the purpose of discovery leishmanicidal secondary metabolites from natural products, crude ethanolic extract (EE) from stems of the Caesalpinia echinata was assayed to verify its in vitro leishmanicidal activity. The EE showed in vitro growth inhibition activities of 90% against amastigote-like of Leishmania (Leishmania) amazonensis. The EE was then submitted to fractionation by Gel Permeation Chromatography (GPC) yielding fifteen fractions (F1 to F15). The same biological assay was performed for the fifteen fractions and the fractions F9 to F11 showed in vitro growth inhibition activities around 80%. The fractions F9 to F11 were pooled to produce an enriched fraction named EF. Evaluation of the acute toxicity of the EE and EF were carried out with Swiss-Webster mice, orally treated by a single oral dose of 300mg of the samples (EE and EF)/kg of body to verify changes in hematological and biochemical profiles and 5.0g of the samples (EE and EF)/kg body to verify the toxicity and safety in using EE and EF as therapeutic agents in the treatment of the leishmaniasis. After preliminary results, the LD50 concentration was estimated to be greater than 5.0g/kg body for both samples (EE and EF) by oral route. The EE and EF of the C. echinata were actives in vitro experiments and nontoxic for mice, moreover these experiments proved to be the first steps towards the development of leishmanicidal agents from C. echinata.
