Δ5,7Sterols from the sponges Ircinia pipetta and Dysidea avara identification of cholesta-5,7,24-trien-3B-OL

1. 1. Δ5,7-sterols have been isolated as pure compounds from the marine sponges Ircinia pipetta (Dictyoceratida:Thorectidae) and Dysidea avara (Dictyoceratida:Dysideidae) by reverse phase HPLC and analyzed by GLC, u.v., mass spectrometry and 1H-NMR. 2. 2. Ircinia pipetta and D. avara have rather similar sterol compositions and contain predominantly Δ5,7-sterols, accompaned by Δ5-sterols. Ergosterol, cholesta-5,7-dien-3β-ol and 24-ethylcholesta-5,7-dien-3β-ol are the major sterols in I. pipetta, while D. avara contains in addition to these three sterols, (24Z)-24-ethylcholesta-5,7,24(28)-trien-3β-ol as the fourth major sterol. 3. 3. Cholesta-5,7,24-trien-3β-ol which previously was not isolated from a marine organism is also present.