New Cytotoxic Terpenoids from Soft Corals Nephthea chabroli and Paralemnalia thyrsoides

A novel cytotoxic diterpenoid, chabrolin A (1) (possessing an unprecedented terpenoid skeleton), as well as three new cytotoxic sesquiterpenoids, parathyrsoidins E–G (2–4), were isolated by cytotoxicity-guided fractionation from soft corals Nephthea chabroli and Paralemnalia thyrsoides. The structures of the new compounds were determined by extensive analysis of spectroscopic data.