Lithothamnin A, the first bastadin-like metabolite from the red alga Lithothamnion fragilissimum.

Lithothamnin A (1) is a new bastadin-like metabolite and represents the first report of this class of molecules from the red alga Lithothamnion fragilissimum. Lithothamnin A contains several novel structural features that distinguish it from other bastadins. These unique structural features include novel aromatic substitution patterns and the presence of a meta-meta linkage between aromatic rings, in addition to the meta-para linkage seen in the bastadins. Lithothamnin A is modestly cytotoxic in a panel of six human tumor cell lines.