Indole alkaloids from the tunicate Aplidium meridianum.

Five new indole alkaloids, meridianins A-E (1-5), have been isolated from the tunicate Aplidium meridianum, which was collected at a depth of 100 m near the South Georgia Islands, and their structures were elucidated by spectroscopic techniques. Compounds 2-5 showed cytotoxicity toward murine tumor cell lines.