Trypanosomicidal kaurane diterpenes from Wedelia paludosa

The diterpenes ent-kaur-16-en-19-oic acid, ent-kaur-9(11),16(17)-dien-19-oi c acid and 3 alpha-angeloiloxy-ent-kaur-16-en-19-oic acid were identified a s trypanosomicidal compounds of the ethanolic extract from the aerial parts of Wedelia paludosa D.C. (Asteraceae), showing activity up to the lowest d ose of 0.68 mg/mL in the in vitro assay against trypomastigotes of T. cruzi , the causative agent of Chagas' disease (American trypanosomiasis), The ot her isolates, friedelan-3 beta-ol, ent-kaur-16 alpha-ol-19-oic acid, beta-a myrin acetate and (22-E)-stigmasta-5,22-dien-3 beta-ol, were inactive. This is the first report on the trypano, somicidal activity of ent-kaur-9(11),1 6(17)-dien-19-oic acid and 3 alpha-angeloiloxy-ent-kaur-16-en-19-oic acids; this effect was already known for ent-kaur-16-en-19-oic acid.