Structural activity relationship studies of zebra mussel antifouling and antimicrobial agents from verongid sponges.

Several dibromotyramine derivatives including moloka'iamine were selected as potential zebra mussel (Dreissena polymorpha) antifoulants due to the noteworthy absence of fouling observed on sponges of the order Verongida. Sponges of the order Verongida consistently produce these types of bromotyrosine-derived secondary metabolites. Previously reported antifouling data for the barnacle Balanus amphitrite(EC50 = 12.

A new coumestan from Tephrosia calophylla.

A new coumestan, tephcalostan (1) has been isolated from the whole plant of Tephrosia calophylla BEDD. together with two known flavonoids, 7-O-methylglabranin (2) and kaempferol 3-O-beta-D-glucopyranoside (3). The structure of tephcalostan was elucidated as 5'-(R)-8, 9-methylenedioxy-5'-isopropenyl-4', 5'-dihydrofurano[2', 3':2, 3]coumestan by extensive one-and two-dimensional (1D- and 2D-)-NMR techniques including (1)H-(1)H correlation spectroscopy (COSY), heteronuclear single quantum coherence (HSQC), heteronuclear multiple bond connectivity (HMBC) and nuclear Overhauser enhancement spectroscopy (NOESY) experiments.