Sangiangols A and B, Two New Dolabellanes from an Indonesian Marine Soft Coral, Anthelia sp.

A new, rare trinor-dolabellane diterpenoid, sangiangol A (1), and one new dolabellane diterpenoid, sangiangol B (2), together with known cembranes and dolabellanes (3–8), were isolated from the ethyl acetate layer of an extract of an Indonesian marine soft coral, Anthelia sp. Compounds 1–8 exhibited moderate cytotoxicity against an NBT-T2 cell line (0.5–10 µg/mL). The structures of the new compounds were determined by analyzing their spectra and a molecular modelling study. A possible biosynthetic pathway for sangiangols A (1) and B (2) is presented. Cytotoxicity requires two epoxide rings or a chlorine atom, as in 4 (stolonidiol) and 5 (clavinflol B).