Acetylene sesquiterpenoid esters from the green alga Caulerpa prolifera

Sixteen secondary metabolites of the green alga Caulerpa prolifera have been isolated, and their chemical structures elucidated by analysis of their spectroscopic data. Two groups of metabolites have been established, with either a 1,2-dihydro- (2a-2i) or a 1,2,3,3'-tetrahydro-2,3-didehydro (3a-3f) caulerpenyne carbon backbone. The terminal vinyl acetoxy group of caulerpenyne was substituted by various fatty acid residues. The antifouling activity of the algal extract was tested in laboratory assays against two of the major groups of fouling organisms (bacteria, microalgae).