RESUMO
The dichloromethane extract of Almeidea coerulea stems yielded the (11-hydroxyrutaecarpine alkaloid reported for the first time from this species) and the triterpene (28-hydroxy-28, 29-dihydrolupeol). The dictamine, skimianine, sitosterol and stigmasterol were also isolated from methanol extract. Extracellular forms of Leishmania amazonensis (promastigotes) was tested with dichloromethane extract and 28-hydroxy-28, 29-dihydrolupeol with showed anti-leishmanial activity above 0.1 mg/mL and 75µg/mL (inhibited 50 percent promastigote growth), respectively.
RESUMO
Infections due to protozoa of the genus Leishmania are a major worldwide health problem, with high endemicity in developing countries. The drugs of choice for the treatment of leishmaniasis are the pentavalent antimonials (SbV), which present renal and cardiac toxicity. Besides, the precise chemical structure and mechanism of action of these drugs are unknown up to date. In order to find new drugs against leishmaniasis, we have been studying extracts of Brazilian trees. In the present study, we have evaluated the effectiveness of an alkaloid extract of Aspidosperma ramiflorum Muell. Arg. (Apocynaceae), against the extracellular forms promastigotes of L. (L.) amazonensis and L. (V.) braziliensis. The alkaloid extract of A. ramiflorum was much more effective against L. (L.) amazonensis (LD50 < 47 µg/ml) than L. (V.) braziliensis. Based on these in vitro results against L. (L.) amazonensis new studies should be made to find the compounds with anti-leishmanial activity.