Meroditerpenoids from the southern Australian marine brown alga Sargassum fallax

Chemical investigation of the Australian marine brown alga Sargassum fallax resulted in the isolation of three meroditerpenoids fallahydroquinone (8), fallaquinone (9) and fallachromenoic acid (10) together with the previously reported compounds sargaquinone (1), sargaquinoic acid (2), sargahydroquinoic acid (3) and sargachromenol (11). Compounds (2) and (3) displayed moderate antitumour activity.