Avaliação in vitro do potencial amebicida de extratos brutos e triterpenos obtidos a partir de Maytenus gonoclada (Celastraceae), sobre Entamoeba histolytica

Abstract

Amebiasis is a human disease caused by the protozoan Entamoeba histolytica, a parasite that causes invasive pathogenic and death of about 100.000 individuals per year worldwide. Some species of the genus Maytenus have been used in Brazilian folk medicine to treat diarrhea. These plants are promising sources of bioactive triterpenes of medicinal interest. Twelve extracts and four triterpenes, previously known, isolated from the branches and roots of Maytenus gonoclada were investigated "in vitro" against potential amoebicide at different time intervals. Crude extracts, lupeol, 3-30-dihydroxy-lup-20 (29)-ene and 3-oxo-11-hydroxylup-20 (29)-ene exhibited no activity against E. histolytica, however, the triterpene tingenone was active. The cytotoxicity was evaluated using the tingenone mononuclear cells human peripheral blood. The IC50 of 8.9 M was found. In this case the cytotoxic dose is very close to the dose amoebicide, precluding further studies with substance "in nature". The cytotoxicity of tingenone on human cells could be restricted to its use in parasite treatments. However the ease of obtaining large amounts and, pointing their use for changes in the structure of the molecule to obtain derivatives with potent activity and lower toxicity.