Antioxidative 7-Oxodehydropodocarpane-Type Trinorditerpenes from the Bark ofTaiwania cryptomerioides

Five new 7-oxopodocarpane-type trinorditerpenes together with 1beta,13,14-trihydroxy-8,11,13-podocarpatrien-7-one ( 1) were isolated from the bark of Taiwania cryptomerioides. By using NMR and other spectral methods, the structures of five new compounds, 14-hydroxy-13-methoxy-8,11,13-podocarpatriene-3,7-dione ( 2), 1beta,14-dihydroxy-13-methoxy-8,11,13-podocarpatrien-7-one ( 3), 13,14-dihydroxy-8,11,13-podocarpatriene-3,7-dione ( 4), 3beta,13,14-trihydroxy-8,11,13-podocarpatrien-7-one ( 5), and 1beta,13,14-trihydroxy-8,11,13-podocarpatriene-2,7-dione ( 6), were elucidated. Compounds 1, 4, 5, and 6 exhibited strong antioxidative activity.