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

Claude Delseth, Yoel Kashman, Carl Djerassi

Research output: Contribution to journalArticlepeer-review

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 1H‐NMR. The sponge contains five conventional Δ5‐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 Δ5,7,22‐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 (24R)‐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 24R 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.

Original languageEnglish
Pages (from-to)2037-2045
Number of pages9
JournalHelvetica Chimica Acta
Volume62
Issue number6
DOIs
StatePublished - 19 Sep 1979

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