New acetogenin peroxides from the Indian sponge Acarnus bicladotylota.

Two new cyclic peroxides (1 and 2) and the known metabolite 3 have been found in the organic extract of the Indian sponge Acarnus bicladotylota. The structure of the new products has been assured by chemical and spectroscopic methods. The absolute stereochemistry of 1-3 has been determined by Mosher's method on the semisynthetic derivative 4.

New scalaranes from the nudibranch Glossodoris atromarginata and its sponge prey.

Two new scalaranes (1 and 2) have been isolated from the dorid nudibranch Glossodoris atromarginataand its prey. The structures were deteremined by spectral techniques and confirmed by chemical methods. Compounds 1 and 3 showed selective cytotoxic activity against human thyroid carcinoma.