In vitro leishmanicidal activity of aurones

A series of aurones with drug-potential for Leishmania infections was ident ified in vitro using both a direct cytotoxicity assay against extracellular promastigotes of Leishmania donovoni, L. infantum, L. enriettii, and L. ma jor, and a test against intracellular amastigote forms of L. donovoni resid ing within murine macrophages. The most active aurone (6-hydroxy-2-[phenyl- methylene]-3(2H)-benzofuranone) had an EC50 of 0.45 mu g/ml in the extra-, and an EC50 of 1.40 mu g/ml in the intracellular assay. Other aurones were active between 0.06-12.50 mu g/ml and 0.04-7.81 mu g/ml, respectively. When tested against murine bone marrow-derived macrophages as a mammalian host cell control, the compounds showed only moderate cytotoxicity (EC50 2.32 to >25.0 mu g/ml). This is the first report on aurones as a new class of natu ral products with leishmanicidal activity.