New briaranes from the Taiwanese Gorgonian Junceella juncea

In addition to the known junceelolide C (4), three new briaranes, juncenolides B (1), C (2), and D (3), have been isolated from the acetone extract of a red Gorgonian Junceella juncea collected in Taiwan. The structures of 1-3 were elucidated on the basis of FABMS and 2D NMR techniques including COSY, HMQC, HMBC, and NOESY experiments. Among them, compound 2 exhibited mild cytotoxicity against human liver carcinoma (HEPA 59T/VGH) and oral epidermoid (KB) carcinoma cells.