Bioassay-directed fractionation of the lipophilic extract of the marine sponge Mycale izuensis led to the isolation of cytotoxic mycalolides including a new compound, 30,32-dihydroxymycalolide A (1). Its structure including absolute stereochemistry was deduced by spectroscopic and chemical methods. Compound 1 was cytotoxic against HeLa cells with an IC(50) value of 2.6 ng/mL.
Laboratory of Aquatic Natural Products Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan.
