Carbon-13 nuclear magnetic resonance studies of allylic hydroxysterols. Assignment of structure of 5.alpha.-cholest-8(14)-ene-3.beta.,7.alpha.,15.alpha.-triol, an inhibitor of sterol synthesis

Tsuda, Mitsuhiro; Parish, Edward J.; Schroepfer, George J.

doi:10.1021/jo01322a021

Cited by 42 publications

(5 citation statements)

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“…Although the 1 H-NMR data of compound 3 were very similar to the literature data, their 13 C-NMR data exhibited a significant difference for C(7). The chemical shift of C(7) of compound 3 was 66.5, while in the literature it was reported as 79.9 ppm, implying that these two HOÀC (7) had different configurations, which were consistent with the observed allylic 7a-and 7b-OH substituent effects, respectively [13] [14]. By comparison with the 13 C-NMR data of conicasterol (5), upfield shifts of 7.3 and 5.5 ppm for C(5) and C(9), respectively, of compound 3 were observed [7], which were ascribed to the syn-axial geffects [10].…”

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confidence: 78%

Oxygenated 4‐Methylidene Sterols from the South China Sea Sponge Theonella swinhoei

Zhang

Lin

2010

Helvetica Chimica Acta

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Two new O-bearing 4-methylidene sterols, 9a-hydroxy-15-oxoconicasterol (1) and 8b-hydroxy-Bnorconicasta-6a-aldehyde (2), were isolated from the EtOH extract of the marine sponge Theonella swinhoei collected from the South China Sea. Their structures were elucidated by spectroscopic data and comparison with known compounds. In addition, spectroscopic data reported for the known 4-methylidene sterol 7a-hydroxyconicasterol (3) were revised.Introduction. -Marine sponges of the genus Theonella have attracted a great deal of attention for their bioactive secondary metabolites, including polyoxygenated aliphatic compounds, unusual cyclic peptides, macrolides, polyethers, polyketides, alkaloids, and sterols [1 -3]. Interestingly, the sterols isolated from the genus Theonella, mainly from T. swinhoei, were found possessing unique 4-methylidene moieties [3 -8], and some of them also have 8,14-seco-frameworks [7] [8]. As part of ongoing investigation on bioactive chemical constituents of marine sponges collected from the South China Sea, studies on the marine sponge T. swinhoei led to the isolation and determination of two new O-bearing 4-methylidene sterols, 9a-hydroxy-15-oxoconicasterol (1) and 8b-hydroxy-B-norconicasta-6a-aldehyde (2), together with a known 4-methylidene sterol 7a-hydroxyconicasterol (3), from the EtOH extract of this sponge. Here, we report the details of isolation and structure elucidation of these compounds.

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supporting

confidence: 78%

Oxygenated 4‐Methylidene Sterols from the South China Sea Sponge Theonella swinhoei

Zhang

Lin

2010

Helvetica Chimica Acta

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“…The ROESY correlations (Fig. 3) C-NMR data (in CDCl 3 ) of 2 were similar to those of 5α-cholest-8(14)-ene-3β,7α,15α-triol, 4) except for big difference on the chemical shifts of the double bond and two oxygenated carbons. An oxygenated quaternary carbon was observed at δ C 103.1 (C, C-15) indicating for a dioxygenated carbon.…”

Section: )supporting

confidence: 57%

“…1) were isolated from the CH 2 Cl 2 residue (3.75 g) by using combined chromatographic methods. Detailed analyses of the spectroscopic data (one dimensional (1D)-, 2D-NMR and MS) and comparisons with previously reported values led to the elucidation of known compounds as 5α-cholest-7-ene-3β,6α-diol (5), 3) 5α-cholest-8(14)-ene-3β,7α-diol (6), 4) and 5α-cholest-7,9(11)-diene-3β-ol (7).…”

Section: Resultsmentioning

confidence: 93%

“…An oxygenated quaternary carbon was observed at δ C 103.1 (C, C-15) indicating for a dioxygenated carbon. In addition, the oxymethine signal was shifted down-field to δ C 76.9 (CH, C-7)/δ H 4.54 (H-7) [versus δ C 73.6 (CH, C-7)/δ H 4.28 (H-7) of 5α-cholest-8(14)-ene-3β,7β-diol 4) ] and the observation of just two hydroxy proton signals at δ H 4.54 (1H, d, J=4.5 Hz, The relative configuration of astropectenol B (2) was assigned by comparison of the 13 C-NMR data with those reported of similar compounds 4,7,8) and by ROESY. The β-orientation of the hydroxy group at C-3 was indicated by the ).…”

Section: )mentioning

confidence: 99%

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Steroidal Constituents from the Starfish <i>Astropecten polyacanthus</i> and Their Anticancer Effects

Thao

Cường

Luyen

et al. 2013

CHEMICAL & PHARMACEUTICAL BULLETIN

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Using various chromatographic methods, four new steroids, astropectenols A-D (1-4), along with three known compounds (5-7) were isolated from a methanol extract of the starfish Astropecten polyacanthus. The structure elucidation was confirmed by spectroscopic methods, including one dimensional (1D)-, 2D-NMR and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS). The CH 2 Cl 2 fraction and compound 7 exhibit potent cytotoxic effects against HL-60 human leukemia cells with the IC 50 of 8.29 µg/mL and 2.70 µM, respectively, comparing to the positive control, mitoxantrone (IC 50 6.80 µM). When HL-60 cells were treated with the CH 2 Cl 2 fraction or compound 7, several apoptosis events like chromatin condensation and the increase of the population of sub-G1 hypodiploid cells were observed. Investigations for the possible mechanism underlying the induction of apoptosis showed that CH 2 Cl 2 fraction or compound 7 induced apoptosis through down-regulation of Bcl-2, up-regulation of Bax, cleavage of caspase-9, cleavage of caspase-3 and cleavage of poly(ADP-ribose) polymerase (PARP) in HL-60 cells. Furthermore, the apoptosis induction of HL-60 cell by CH 2 Cl 2 fraction or compound 7 was attended by the decreasing of phospho-extracellular signal-regulated kinase (ERK) 1/2 and C-myc. These results indicated that the CH 2 Cl 2 fraction and compound 7 could induce the apoptosis of HL-60 cells via the inactivation of ERK 1/2 and the decrease of C-myc. Our finding suggested the potential using of the CH 2 Cl 2 fraction and compound 7 for leukemia treatment. Key words Astropecten polyacanthus; starfish; oxygenated steroid; cytotoxic; apoptosisEchinoderms represent an outstanding source of polar steroids of a great structural diversity, showing various biological activities. Among five living classes of the phylum Echinodermata, two classes Asteroidea (starfish) and Ophiuroidea (brittle stars) are especially rich in polar steroids.1) The research on starfish has expanded rapidly over the past few years, which has been prompted by the discovery of a variety of unique structures and the interest in their pharmacological properties. Starfish have attracted organic chemists, biochemists, and pharmacologists as a fascinating source of bioactive marine natural products, especially steroids and steroidal glycosides. 2)Some polyhydroxylated steroids from starfish exhibited antibacterial and cytotoxic activities. 1)In our screening research for anti-cancer agents from Vietnamese echinoderms, we found the starfish Astropecten polyacanthus to possess significant cytotoxic effects. As part of our continuing investigations on this starfish, we report herein the isolation, structural elucidation, and evaluation of anticancer activity of extracts and seven steroids, including four new compounds 1-4, from the starfish A. polyacanthus.

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“…Among the most useful derivatives, the acetate is often used for the assignment of the hydroxyl-bearing carbon and adjacent carbons of steroids and triterpenoids [1,14,18,[20][21][22][23]. The acetylation of the 3~-hydroxyl group of sterols produces a characteristic downfield shift of the C-3 signal (-3p.p.m.…”

Section: Derivatizationmentioning

confidence: 99%

13C NMR spectroscopy of sterols

Goad¹,

Akihisa²

1997

Analysis of Sterols

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Carbon-13 nuclear magnetic resonance studies of allylic hydroxysterols. Assignment of structure of 5.alpha.-cholest-8(14)-ene-3.beta.,7.alpha.,15.alpha.-triol, an inhibitor of sterol synthesis

Cited by 42 publications

References 13 publications

Oxygenated 4‐Methylidene Sterols from the South China Sea Sponge Theonella swinhoei

Oxygenated 4‐Methylidene Sterols from the South China Sea Sponge Theonella swinhoei

Steroidal Constituents from the Starfish <i>Astropecten polyacanthus</i> and Their Anticancer Effects

13C NMR spectroscopy of sterols

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