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New Triterpenoid Sulfates from the Red Alga Tricleocarpa fragilis

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journal contribution
posted on 21.01.2000, 00:00 by F. David Horgen, Bryan Sakamoto, Paul J. Scheuer
Ten new sulfated terpenoids, including six cycloartenol sulfates (16), two 29-nor-cycloartenol sulfates (7,8), and two 29-nor-lanosterol sulfates (9,10), were isolated from brine shrimp-toxic fractions of the methanolic extract of the red alga Tricleocarpa fragilis collected in Hawaiian waters. Structures 110 were elucidated by spectral methods, and the absolute stereochemistry for compound 1 at C23 was determined by Mosher analysis. Compounds 7 and 10 showed brine shrimp toxicity at 50 μg/mL, while 1 and 3 showed substantial activity at 17 μg/mL. Compounds 2, 4, 5, and 9 were inactive. In cytotoxicity assays, compounds 110 were inactive at concentrations tested.