Abstract
Two hydroperoxysterols 24-hydroperoxy-24-vinyl-cholesterol (1) and 29-hydroperoxystigmasta-5,24(28)-dien-3β-ol (2), and fucosterol (3) were isolated from the brown alga Turbinaria ornata (Sargassaceae). Hydroperoxide 2 is a new natural compound and was converted into 29-hydroxystigmasta-5,24 (28)-dien-3β-ol
(4) by reaction with LAH. Sterols 1, 2, and 4 exhibited cytotoxicity against various cancer cell lines.
