Trypanocidal Activity of Abietane Diterpenoids from the Roots of Craniolaria annua

A chloroform extract from roots of Craniolaria annua provided six new C-11 unsubstituted abietanes, 14-hydroxy-6,12-dione-7,9(11),13-abietatriene (1), 14-hydroxy-12-oxo-7,9(11),13abietatriene (2), 6,12,14-trihydroxyabieta-5,8,11,13-tetraen-7-one (3), ar-abietatriene-12-ol6,7-dione-14,16-oxide (4), ar-abietatriene-12,16-diol-14,16-oxide (5) and ar-abietatriene-12-ol7-one-14,16-oxide (6), and two known compounds, ferruginol and stigmasterol. The structures of both the new and known compounds were established by spectroscopic methods. Abietane 1 gave 14-hydroxy-6-oxoferruginol (1A) upon treatment with NaBH4. Abietanes 1, 1A, 3Ð5 and ferruginol showed cytotoxic effects against trypomastigote and epimastigote forms of Trypanosoma cruzi and against fibroblastic Vero cells.