In‐vitro trypanocidal activity evaluation of crude extract and isolated compounds from Baccharis dracunculifoliaD. 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 mg mL−1, displayed 100% lysis of trypomastigote forms of the Y strain of Trypanosoma cruzi(2 times 106parasites 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‐(dihydrocinnamoyloxy)‐cinnamic acid (6), and friedelanol (7). The chemical structures of all compounds were established by UV‐vis, 1H and 13C NMR data analysis in comparison with the literature. Compounds 1and 3were the most active in the trypanocidal assay, showing IC50 values (inhibitory concentration required for 50% inhibition) of 247.6 and 249.8 μM, respectively. Compounds 2, 4, and 6displayed moderate activity, whilst compounds 5and 7were inactive.