Echinosulfonic acid D: an ESI MS<i> ⁿ </i> evaluation of a new cytotoxic alkaloid from the New-Caledonian sponge <i>Psammoclemma</i> sp.

Abstract

A new bromoindolesulfonic acid derivative, echinosulfonic acid D (1) was isolated from the New-Caledonian sponge Psammoclemma sp. in a minute quantity. The structure of the alkaloid was established by spectroscopic methods and, in particular, by ESI MSn experiments. Echinosulfonic acid D was cytotoxic to KB cells (IC50 2 microg/mL).