Halymecins, new antimicroalgal substances produced by fungi isolated from marine algae.

Novel antimicroalgal substances halymecins A (1), B (2) and C (3) were isolated from the fermentation broth of a Fusarium sp. and halymecins D (4) and E (5) from an Acremonium sp. The structures of these halymecins, Fig. 1, were determined based on extensive 2D NMR studies as well as mass spectral data. These chemical structures are conjugates of di- and trihydroxydecanoic acid. Halymecin A showed antimicroalgal activity against Skeletonema costatum.