Antileishmanial and trypanocidal activity of brazilian Cerrado plants

The side effects and the emerging resistance to the available drugs against leishmaniasis and trypanosomiasis led to the urgent need for new therapeutic agents against these diseases. Thirty one extracts of thirteen medicinal plants from the Brazilian Cerrado were therefore evaluated in vitro for their antiprotozoal activity against promastigotes of Leishmania donovani, and amastigotes of Trypanosoma cruzi. Among the selected plants, Casearia sylvestris var. lingua was the most active against both L. donovani and T. cruzi. Fifteen extracts were active against promastigotes of L. donovani with concentrations inhibiting 50% of parasite growth (IC50) between 0.1-10 µg/ml, particularly those of Annona crassiflora (Annonaceae), Himatanthus obovatus (Apocynaceae), Guarea kunthiana (Meliaceae), Cupania vernalis (Sapindaceae), and Serjania lethalis (Sapindaceae). With regard to amastigotes of T. cruzi, extracts of A. crassiflora, Duguetia furfuracea (Annonaceae), and C. sylvestris var. lingua were active with IC50 values between 0.3-10 µg/ml. Bioassay fractionations of the more active extracts are under progress to identify the active antiparasite compounds

<i>In vitro</i> investigation of Brazilian Cerrado plant extract activity against <i>Plasmodium falciparum</i>, <i>Trypanosoma cruzi</i> and <i>T. brucei gambiense</i>

<p>The threatened Brazilian Cerrado biome is an important biodiversity hotspot but still few explored that constitutes a potential reservoir of molecules to treat infectious diseases. We selected eight Cerrado plant species for screening against the erythrocytic stages of <i>Plasmodium falciparum</i>, human intracellular stages of <i>Trypanosoma cruzi</i> and bloodstream forms of <i>T. brucei gambiense</i>, and for their cytotoxicity upon the rat L6-myoblast cell line. Bioassays were performed with 37 hexane, ethyl acetate and ethanol extracts prepared from different plant organs. Activities against parasites were observed for 24 extracts: 9 with anti-<i>P. falciparum</i>, 4 with anti-<i>T. cruzi</i> and 11 with anti-<i>T. brucei gambiense</i> activities. High anti-protozoal activity (IC₅₀ values < 10 μg/mL) without obvious cytotoxicity to L6 cells was observed for eight extracts from plants: <i>Connarus suberosus</i>, <i>Blepharocalyx salicifolius</i>, <i>Psidium laruotteanum</i> and <i>Myrsine guianensis</i>. Overall, studies of plant extracts will contribute to increase the biodiversity knowledge essential for Cerrado conservation and sustainable development.</p