A new polyacetylenic fatty acid and other secondary metabolites from the Chinese green alga Caulerpa racemosa (Caulerpaceae) and their chemotaxonomic significance

A new polyacetylenic fatty acid, (8E,12Z,15Z)-10-hydroxy-8,12,15-octadecatrien-4,6-diynoic acid (1), together with five known metabolites, including two linear diterpenes (3 and 4) and three sterols (5-7), has been isolated from the Chinese green alga Caulerpa racemosa. Its structure was determined on the basis of extensive spectroscopic analysis. Compound represents the first example of polyacetylenic lipids from marine algae up to now, while compound 4 is characterized for the first time in the Caulerpaceae. Furthermore, the chemotaxonomic significance of these compounds was also summarized. (C) 2011 Elsevier Ltd. All rights reserved.