Sargachromanols as inhibitors of Na +/K + ATPase and isocitrate lyase

Sargachromanol D ( 4) and H ( 8) were found to be strong Na +/K + ATPase inhibitors, with IC 50 values of 3.6 and 4.6 μM, respectively. Sargachromanols A–P ( 1– 16), 16 meroterpenoids of the chromene class isolated from the brown alga Sargassum siliquastrum, were evaluated for their inhibitory activities toward Na +/K + ATPase from porcine cerebral cortex and isocitrate lyase (ICL) from Candida albicans. These studies led to the identification of compounds 4, 6, 8, and 12 as potent Na +/K + ATPase inhibitors. Compounds 12, 13, and 16 exhibited moderate ICL inhibitory activity. Compound 12 also showed weak antibacterial activity. The preliminary structure–activity relationship of these compounds is described to elucidate the essential structural requirements.