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DOI: 10.1055/s-0034-1382485
Leishmanicidal sesquiterpene lactones from Tithonia diversifolia
Sesquiterpene lactones (SLs) are recognized as a class of natural compounds with a wide spectrum of biological activities, including against Leishmania spp. In this work, a SL rich extract from Tithonia diversifolia (SLRE) was tested against promastigote forms of L. braziliensis. This result revealed that SLRE is a rich source of potent leishmanicidal compounds (LD50= 1.5 ± 0.50 µg/mL). Therefore eight sesquiterpene lactones from SLRE were investigated and three of them (1 – 3) showed potent leishmanicidal effect with high level of selectivity, displaying LD50 values (ranging from 21.2 ± 8.0 to 37.4 ± 7.1µM) similar to that observed for positive control (hygromycin B; 15.1 ± 0.9µM). Due to these results, compounds 1 – 3 were evaluated at their LD50 concentrations on intracellular amastigotes. After 48 hours of treatment these SLs reduced the internalization of parasites in about 58, 51 and 27%, respectively, in comparison with negative control. The results described herein bring new perspectives in the study of STL and may provide promising leads for the development of new drugs against leishmaniasis.
The authors thank to FAPESP for funds and grants (process number 2014/04281 – 7)