Five new degraded diterpenoids from Trigonostemon xyphophylloides

Five new degraded diterpenoids trigoxyphins J-N (1-5) together with four known analogues (6-9) were isolated from Trigonostemon xyphophylloides. Trigoxyphins K and L have a novel carbon skeleton. Trigoxyphin N (5) showed moderate cytotoxicities against two tumor cell lines.