New briaranes from the South China Sea gorgonian Junceella fragilis

Three new briarane diterpenes, junceellonoids C - E (1 - 3), along with six known briaranes, junceellin A (4), praelolide (5), and junceellolides A-D (6 - 9), were isolated from the EtOH/CH2Cl2 extracts of the South China Sea gorgonian coral Junceella fragilis. The structures of 1 - 3 were established by extensive spectroscopic analysis, including 1D- and 2D-NMR data. Compounds I and 2 exhibited mild cytotoxicity against human galactophore carcinoma (MDA-mB-231 and MCF-7) cells at the concentration of 100 mu m.