In-vitro trypanocidal activit evaluation of crude y extract and isolated compounds from Baccharis dracunculifolia D.C. (Asteraceae)

We have performed a trypanocidal bioactivity-guided study of Baccharis dracunculifolia (Asteraceae), the main botanical origin of Brazilian green propolis. The leaf rinse extract of B. dracunculifolia, at a concentration of 3.0 mgmL(-1), displayed 100% lysis of trypomastigote forms of the Y strain of Trypanosoma cruzi (2 x 10(6) parasites mL(-1)). The chromatographic fractionation of the leaf rinse, using several techniques, afforded the isolation of the compounds isosakuranetin (1), aromadendrin 4'-methylether (2), baccharis oxide (3), ferulic acid (4), dihydrocinnamic acid (5), 3-prenyl-4-(dihydro-cinnamoyloxy)-cinnamic acid (6), and friedelanol (7). The chemical structures of all compounds were established by UV-vis, H-1 and C-13 NMR data analysis in comparison with the literature. Compounds 1 and 3 were the most active in the trypanocidal assay, showing IC50 values (inhibitory concentration required for 50% inhibition) of 247.6 and 249.8 muM, respectively. Compounds 2, 4, and 6 displayed moderate activity, whilst compounds 5 and 7 were inactive.