The sterols of the asteroid Echinaster sepositus

1. 1. The free sterol mixture of starfish Echinaster sepositus was found to contain over 25 components. Most of them have been identified by mass and NMR spectral analyses of enriched fractions as well as of pure compounds. 2. 2. The major components were Δ7-sterols, and lesser amounts of Δ5- and ring saturated sterols were also present. 3. 3. (22E)-24-nor-5α-cholesta-7,22-dien-3β-ol (asterosterol), (22E)-27-nor-24(S)-methyl-5α-cholesta-7,22-dien-3β-ol (amuresterol), and 5α-cholesta-7,22-dien-3β-ol, probable biogenetic precursor of the minor 22,23-epoxy-sapogenins from the same starfish, are present in a relatively large proportion. 4. 4. Two new C-30 sterols, (24E)- and (24Z)-24-propyl-5α-cholest-24(28)-en-3β-ol, have been isolated and their structures determined by comparative physical methods, NMR and mass spectrometry. © 1980