Irciniasulfonic acid was obtained. from a marine sponge of Ircinia sp. Spec
troscopic and chemical analyses revealed its structure consists of three di
fferent kinds of acids, i.e. common fatty acids, a novel unsaturated branch
ed C-10 fatty acid and an isethionic acid. Irciniasulfonic acid and deacyl
irciniasulfonic acid reverse multidrug resistance in human carcinoma cells
caused by overexpression of membrane glycoprotein. (C) 2001 Elsevier Scienc
e Ltd. All rights reserved.