Anti-malarial, anti-trypanosomal, and anti-leishmanial activities of jacaranone isolated from Pentacalia desiderabilis

Leishmaniasis, Chagas disease, and malaria affect the poorest population around the world, with an elevated mortality and morbidity. In addition, the therapeutic alternatives are usually toxic or ineffective drugs especially those against the trypanosomatids. In the course of selection of new anti-protozoal compounds from Brazilian flora, the C[H.sub.2][Cl.sub.2] phase from MeOH extract obtained from the leaves of Pentacalia desiderabilis (Vell.) Cuatrec. (Asteraceae) showed in vitro anti-leishmanial, anti-malarial, and antitrypanosomal activities. The chromatographic fractionation of the C[H.sub.2][Cl.sub.2] phase led to the isolation of the bioactive compound, which was characterized as jacaranone [methyl (1-hydroxy-4-oxo-2,5-cyclohexandienyl) acetate], by spectroscopic methods. This compound showed activity against promastigotes of Leishmania (L.) chagasi, Leishmania (V.) braziliensis,and Leishmania (L.). amazonensis showing an [IC.sub.50] of 17.22, 12.93, and 11.86 µg/mL, respectively. Jacaranone was also tested in vitro against the Trypanosoma cruzi trypomastigotes and Plasmodium falciparum chloroquine-resistant parasites (K1 strain) showing an [IC.sub.50] of 13 and 7.82 µg/mL, respectively, and was 3.5-fold more effective than benznidazole in anti-Trypanosoma cruzi assay. However, despite of the potential against promatigotes forms, this compound was not effective against amastigotes of L. (L.) chagasi and T. cruzi. The cytotoxicity study using Kidney Rhesus monkey cells, demonstrated that jacaranone showed selectivity against P. falciparum (21.75 µg/mL) and a selectivity index of 3. The obtained results suggested that jacaranone, as other similar secondary metabolites or synthetic analogs, might be useful tolls for drug design for in vivo studies against protozoan diseases.