Three new pimaren diterpenoids from marine mangrove plant, Bruguiera gymnorrhiza.

Three new pimaren diterpenoids, ent-8(14)-pimarene-15R, 16-diol (1), ent-8(14)-pimarene-1alpha,15R,16-triol (2), and (5R, 9S, 10R, 13S, 15S)-ent-8(14)-pimarene-1-oxo-15R,16-diol (3), along with three known diterpenoids (4-6) have been isolated from the stem of mangrove plant Bruguiera gymnorrhiza. The structures of compounds 1-3 were determined by extensive spectroscopic (2D NMR, MS, IR, and CD) analysis, and 3 and 5 showed moderate cytotoxic activities against L-929 and K562, respectively.