Acetate-Derived Metabolites from the Brown Alga Lobophora variegata.

Seven new nonadecaketides (1-7), lobophorols A-C, lobophopyranones A and B, and lobophorones A and B, along with the first naturally occurring related metabolites (8-10), were isolated from specimens of Lobophora variegata collected from the Canary Islands. Their structures were determined by extensive spectroscopic methods. In addition, an insight into the biosynthesis of these compounds on the basis of the involvement of type III polyketide synthases is proposed. Lobophorol A (1) showed significant antibacterial activity against Staphylococcus aureus.