In vitro antileishmanial and antitrypanosomal activities of flavanones from Baccharis retusa DC. (Asteraceae)

Abstract Leishmaniasis and Chagas’ are parasitic protozoan diseases that affect the poorest population in the world, causing a high mortality and morbidity. As a result of highly toxic and long-term treatments, novel, safe and more efficacious drugs are essential. In this work, the CH 2 Cl 2 phase from MeOH extract from the leaves of Baccharis retusa DC. (Asteraceae) was fractioned to afford two flavonoids: naringenin ( 1 ) and sakuranetin ( 2 ). These compounds were in vitro tested against Leishmania spp. promastigotes and amastigotes and Trypanosoma cruzi trypomastigotes and amastigotes. Compound 2 presented activity against Leishmania ( L. ) amazonensis , Leishmania ( V. ) braziliensis , Leishmania ( L. ) major , and Leishmania ( L. ) chagasi with IC 50 values in the range between 43 and 52 μg/mL and against T. cruzi trypomastigotes (IC 50  = 20.17 μg/mL). Despite of the chemical similarity, compound 1 did not show antiparasitic activity. Additionally, compound 2 was subjected to a methylation procedure to give sakuranetin-4′-methyl ether ( 3 ), which resulted in an inactive compound against both Leishmania spp. and T. cruzi . The obtained results indicated that the presence of one hydroxyl group at C-4′ associated to one methoxyl group at C-7 is important to the antiparasitic activity. Further drug design studies aiming derivatives could be a promising tool for the development of new therapeutic agents for Leishmaniasis and Chagas’ disease.