Novel oxylipin metabolites from the brown alga Eisenia bicyclis

Nine novel oxylipin metabolites together with several known ones were isolated from the brown alga Eisenia bicyclis. Five (1-5) of them are ecklonialactone derivatives containing a chlorine or an iodine atom, and two (6 and 7) are cymathere type oxylipins with a lactone ring or a chlorine atom. The structures of these oxylipin metabolites were confirmed by NMR and mass spectroscopy and compared with spectral data in the literature. The postulated biosynthetic pathway of these metabolites is discussed.