15β-Senecioyl-oxy--kaur-16-en-19-oic Acid, a Diterpene Isolated from , as Promising Oral Compound for the Treatment of Schistosomiasis.

Praziquantel is the only available drug to treat schistosomiasis, and therefore, urgent studies must be performed to identify new anthelmintic agents. This study reports the anthelmintic evaluation of two related -kaurane diterpenes isolated from aerial parts of (Asteraceae), -kaur-16-en-19-oic acid () and 15β-senecioyl-oxy--kaur-16-en-19-oic acid () against and in a murine model of schistosomiasis. Both compounds exhibited activity with lethal concentration 50% (LC) values of 26.1 μM () and 11.6 μM () as well as reduced toxicity against human cell lines, revealing a good selectivity profile, mainly with compound (selectivity index > 10). Compound also decreased egg production and caused morphological alterations in the parasite reproductive system. In mice infected with , oral treatment with compound at 400 mg/kg, the standard dose used in this model of schistosomiasis, caused a significant reduction in a total worm burden of 61.9% ( < 0.01). egg production, a key mechanism for both transmission and pathogenesis, was also markedly reduced. In addition, compound achieved a significant reduction in hepatosplenomegaly. Therefore, the diterpene 15β-senecioyl-oxy--kaur-16-en-19-oic acid () has an acceptable cytotoxicity profile and is orally active in a murine schistosomiasis model.