Ergosta-5,7,9(11), 22-tetraen-3β-ol and its 24ξ-Ethyl Homolog, Two New Marine Sterols from the Red Sea Sponge Biemna fortis
✍ Scribed by Claude Delseth; Yoel Kashman; Carl Djerassi
- Publisher
- John Wiley and Sons
- Year
- 1979
- Tongue
- German
- Weight
- 589 KB
- Volume
- 62
- Category
- Article
- ISSN
- 0018-019X
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✦ Synopsis
Abstract
The steroidal components of a Red Sea sponge, Biemna fortis, were fractionated through reversed phase HPLC. and analyzed by a combination of physical methods, including high resolution GC./MS. and 360 MHz ^1^H‐NMR. The sponge contains five conventional Δ^5^‐sterols, 1a–c, 1e, 1g, which comprise about 25% of the mixture and 2,5% of gorgosterol (1h), a sterol never found before in Porifera. Three Δ^5,7,22^‐sterols were also present as major components in the mixture (∼70%): cholesta‐5,7,22‐trien‐3β‐ol (2a), ergosta‐5,7,22‐trien‐3β‐ol (2c) and (24__R__)‐ethylcholesta‐5,7,22‐trien‐3β‐ol (2e) whereas two new tetra‐unsaturated sterols were identified in minor amounts (2%): ergosta‐5,7,9(11),22‐tetraen‐3β‐ol (3c) and 24ξ‐ethylcholesta‐5,7,9 (11), 22‐tetraen‐3β‐ol (3e or 3f). NMR. spectroscopy made possible the assignment of a 24__R__ configuration for all the C(24) substituted sterols isolated in sufficient amount from the mixture. The possible symbiotic, dietary or biosynthetic origins of these sterols are discussed.