Isolation of an Unusual 2-Aminoimidazolium Salt of Steroid Trisulfate from a Marine Sponge Topsentia sp.

Abstract

An unusual salt comprised of three 2-aminoimidazolium cations and halistanol sulfate anion was isolated from a marine sponge Topsentia sp. along with known halistanol trisodium salt. Their structures were determined by spectroscopic methods. The number of 2-aminoimidazoliumions in the molecule was estimated from the signal intensity in the ¹H NMR spectrum, and that of sodium ions was from the atomic absorption spectrometry. This is the first report of a unique salt consisted of 2-aminoimidazolium cations in natural source. Both halistanol sulfate salts showed antimicrobial activities against Flavobacterium marinotypicum and Mortierella ramaniana at 10 μg/disk.