SummaryThe steroidal components of 2 marine sponges, Terpios zeteki (from Hawaii) and Dysidea herbacea (from Australia) were fractionated through a combination of chromatographic methods, including reversed phase HPLC., and were analyzed by a combination of physical methods, including high resolution GC.-MS. and 360 MHz 'H-NMR. T. zeteki contains 6 conventional 5a-stanols which comprise 91% of the sterol mixture, and traces (0.5%) of a new C26 sterol, 5a-24-norcholestan-3/3-01. Minor amounts of conventional d5-sterols (6.5%) and of a single d4-3-ketosteroid (1.5%) were also present. In contrast, the Australian sponge (D. herbacea) contains 3 d5,7-sterols which comprise 1.5% of the sterol mixture, and one new C29 sterol, (24 Z)-stigmasta-5,7,24 (28)-trien-38-01, as the major component (75%). In addition, minor amounts of conventional 5a-stanols (0.5%), d5-sterols (5%) and 5a-d7-sterols (18%) were present in this complex sterol mixture. The possible dietary or endosymbiotic origins of these sterols are discussed.

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