Cytotoxic oxasqualenoids from the red alga Laurencia viridis

Three new polyether squalene derivatives 15-dehydroxythyrsenol A (2), prethyrsenol A (3) and 13-hydroxyprethyrsenol A (4) have been isolated from the red alga Laurencia viridis. Their structures were determined through the interpretation of NMR spectroscopic data and chemical correlations. In addition, four semi-synthetic compounds modulating the solubility of the lead compound dehydrothyrsiferol (1) were prepared without loss of activity. The cytotoxicity of the new compounds exhibited low mu M activities. In order to explain their biological properties, docking simulations of the natural and synthetic compounds onto the alpha v beta 3 integrin binding region were carried out. (C) 2011 Elsevier Masson SAS. All rights reserved.