New Compounds From the Deep‐sea Sponge <i>Mycale lingua</i>

Three compatible solutes and one compound of unknown ecological function were isolated and characterized from the deep-sea sponge Mycale lingua (Bowerbank, 1866), collected from Tisler reef in Norway. These included the first isolation of asterubine and sulcatin from M. lingua as well as two new sulcatin analogues, sulcatin B and sulcatin C, which have not previously been reported from natural sources. Compound structures were elucidated through high-resolution liquid chromatography-mass spectrometry, and one- and two-dimensional nuclear magnetic resonance spectroscopic methods. All four compounds were tested in tau-tau aggregation assays to determine if they had potential for the treatment of Alzheimer's disease. No activity was displayed in either the cell-free or cell-based tau aggregation assays for any of the compounds.