Secondary metabolites from the marine alga Caulerpa brownii (Chlorophyta)

The green seaweed Caulerpa brownii ( Chlorophyta, Caulerpaceae) occurs in Tasmania in two morphological forms ( branched and unbranched) and each form has a different profile of diterpenoid secondary metabolites. Unbranched specimens gave rise to the novel secondary metabolites 11, 13, 14, 17, and 18, the secondary metabolite 8 that has been isolated for the first time as a natural product, as well as the known compounds 1 and 3 - 7. Branched specimens of C. brownii yielded the novel terpenoid esters 21 and the known compounds 1 and 2.