A seco-laurane sesquiterpene and related laurane derivatives from the red alga Laurencia okamurai Yamada

A ring-cleaved sesquiterpene named seco-laurokamurane (1) and six related derivatives (2-7) were isolated from red alga Laurencia okamurai Yamada, together with six known sesquiterpenes. Their structures were elucidated by detailed analysis of spectroscopic data. Compound 1 possesses an unprecedented carbon skeleton named seco-laurokamurane. Selected compounds had moderate antifungal activity and cytotoxicity.121