Marine natural products: highly functionalized steroids (12β-hydroxy-24-norcholesta-1,4,22-trien-3-one and 12β-acetoxy-24-norcholesta-1,4,22-trien-3-one) from the sea raspberry, Gersemiarubiformis

Abstract

Two new C26 steroid Δ1.4-dien-3-ones 5 and 6 with 12β oxygen functions have been isolated from the soft coral Gersemiarubiformis and their structures elucidated from their spectral data and chemical transformations.

New Cytotoxic Oxygenated Sterols from the Marine Bryozoan Cryptosula pallasiana

“…Comparing their MS and NMR data with those reported in the literature, the known sterols were identified as (23 Z )-cholesta-5,23-diene-3 β ,25-diol ( 7 ) [ 15 ], cholest-5-ene-3 β ,7 β -diol ( 8 ) [ 16 ], cholest-5-ene-3 β ,7 α -diol ( 9 ) [ 16 ], (22 E )-3 β -hydroxy-24-norcholesta-5,22-dien-7-one ( 10 ) [ 16 ], (22 E )-3 β -hydroxycholesta-5,22-dien-7-one ( 11 ) [ 16 ], 3 β -hydroxycholest-5-en-7-one ( 12 ) [ 16 ] and (4 E ,22 E )-12 β -hydroxy-24-norcholesta-1,4,22-trien-3-one ( 13 ) [ 17 ], respectively. The cis -double bonds between C-23 and C-24, together with an oxygenated hydroxyl group at C-25 in the side chain of 7 is scarce in natural sterols.…”

“…Sterols 8 - 12 were previously isolated from two marine sponges Cliona copiosa [ 16 ] and Stelodoryx chlorophylla [ 18 ], and sterols 8 - 9 were also isolated from a soft coral Dendronephthya gigantean [ 19 ] and a marine bryozoan Biflustra grandicella [ 20 ]. Compound 13 was a highly functionalized C 26 steroid Δ 1,4 -dien-3-one with 12 β oxygen function, which is a rare structural feature among sterols and has been isolated from soft coral Gersemia rubiformis [ 17 ]. However, all of the known sterols were isolated for the first time from this species.…”

Electron impact induced fragmentations of the 1,4-diene analogues of steroid hormones and related steroids

“…In an attempt to confirm the identity of the ion at m / z 121, as originating exclusively by fragmentation a (as ion at m / z 122) but with the migration of one hydrogen atom, we obtained the mass spectra of 4,6,6,17a,21,21 ,21-2H,-pregna-l ,4-diene-3,20-dione ( 9 ) and of 4,6,6,21,21,21-2H,-17a-hydroxypregna-l,4diene-3,20-dione (10). The calculated deuterium distribution is shown in Table 2.…”

“…From ions 45 and 46 we determined that in compound 9, 75% of the molecules 0 dH are trideuterated at C-21 and 25% are dideuterated at that position, while for compound 10 the distribution was 87% and 13% respectively. From the ions at m / z 194 and 195 (fragmentation b) of 9 we calculated that 85% of the molecules were deuterated at C-17. The deuterium distribution at positions 4 and 6 was calculated from these data and by considering the deuterium distribution obtained from the molecular ion.…”

Anti-inflammatory Constituents from Solanum nigrum

“…Spirostane-type compounds with C26 have not been reported from natural sources so far while a few steroids with C26 have been found in the marine organisms. 29,30 All the compounds obtained from the fruits of S. nigrum were evaluated for their inhibitory activities on LTC 4 release, and the results were summarized in Table 2. Of the compounds tested, compound 4 exhibited the most potent inhibition of LTC4 release with an IC50 value of 2.2 µM (the positive control, zileuton, 0.75 µM).…”