Abstract

Four new triterpenoids with a squalene carbon skeleton martiriol 7, pseudodehydrothyrsiferol 8, dioxepandehydrothyrsiferol 9 and 16-epihydroxydehydrothyrsiferol 10 have been isolated from the red alga Laurencia viridis. The structures were determined through the interpretation of their spectral data and the relative stereochemistries were proposed on the basis of ROESY and NOEDIFF data. Their cytotoxic activities were evaluated. (C) 2001 Elsevier Science Ltd. All rights reserved.