Terpenoids from the Soft Coral <i>Stereonephthya bellissima</i>

A detailed chemical study of the extract from the soft coral Stereonephthya bellissima resulted in the isolation and identification of seven new sesquiterpenoids, bellissinanes A–G (1–7), along with four new diterpenes (8–11). Bellissinane A (1) is the third reported nardosinane-type sesquiterpene bearing a 6/5/6 tricyclic system. Bellissinanes C and D (3, 4) contain a phenylethylamine fragment, which is relatively unusual in marine organisms. Bellissinanes E–G (5–7) belong to the rare class of nornardosinane sesquiterpenoids. Structurally uncommon octahydro-1H-indenyl-type and prenyleudesmane-type skeletons were characterized for herpetopanone B (8) and bellissimain A (9), respectively. Bellissinane E (5) exhibited in vivo angiogenesis-promoting activity.