NEW CYTOTOXIC METABOLITES FROM THE SPONGE CACOSPONGIA-SCALARIS

The sponge Cacospongia scalaris from Tarifa Island, Spain, contains in addition to five known compounds (1-5), the new scalarane sestertepen es 18-epi-scalaradial (6), 19-dihydroscalaradial (7), 12-epi-acetylsca larolide (8), and 16-acetylfuroscalarol (9) together with three uncomm on norscalaranes norscalaral A (10), norscalaral B (11), and norscalar al C (12). The structures were elucidated by interpretation of spectra l data. 18-epi-Scalaradial (6) represents the missing, stereoisomer on structure-activity studies carried out with compounds of this series and did not react with methylamine. The new compounds isolated from C. scalaris showed significant in vitro cytotoxicity against five tumor cell lines with 18-epi-scalaradial showing the greatest activity (ED(5 0) = 0.2 mu g/mL).