Dichotellides A-E, five new iodine-containing briarane type diterpenoids from Dichotella gemmacea

Five new briarane type diterpenoids, dichotellides A-E (1-5), were isolated from the South China Sea gorgonian Dichotella gemmacea together with four known analogues (6-9). Compounds 1-5 represent the first examples of iodine-containing briarane type diterpenoids from nature. The structures of these diterpenoids were elucidated by spectroscopic analysis, including 1D, 2D-NMR, and HRESIMS, and the absolute configuration of 1 was further confirmed by single crystal X-ray diffraction analysis. All the isolates were evaluated for cytotoxicity activity against four human tumor cell lines, and only 3 exhibited marginal activity against SW1990 (human pancreatic cancer). (C) 2010 Elsevier Ltd. All rights reserved.