The 220 MHz NMR spectra of phytosterols

Rubinstein, I.; Goad, L. John; Clague, A. D. H.; Mulheirn, L. J.

doi:10.1016/s0031-9422(00)89083-4

Cited by 367 publications

(244 citation statements)

References 22 publications

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“…1 H NMR spectra of 4-8 and 12, as well as 13 C NMR of 6, agreed with those previously reported. [19][20][21][22] In the 1 21,23 confirmed their structures. The TMSsterol at T RR′ ) 1.325 showed an MS which matched both mass spectra of TMS derivatives from sitosterol (21) 12 and clionasterol (24-epi-sitosterol).…”

Section: Resultsmentioning

confidence: 85%

Phycomysterols and Other Sterols from the Fungus Phycomyces blakesleeanus

Oltra

et al. 1998

J. Nat. Prod.

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In the search for novel bioactive products from filamentous fungi, sterols and triterpenoids found in Phycomyces blakesleeanus were analyzed using semipreparative HPLC, GC-MS, and NMR techniques. Structures proposed for the three new compounds identified, phycomysterol A (1), phycomysterol B (2), and neoergosterol (3), were confirmed by chemical synthesis. Phycomysterols possess a new natural 19-norergostane skeleton with an aromatic B ring. Phycomysterol A showed anti-HIV activity.Fungi have been one of the main natural sources of biologically active substances since the discovery of antibiotics. Searching for new bioactive products from filamentous fungi, chemical analysis and biological screening of metabolites from Gibberella fujikuroi have been the subject of our work over the past few years. [1][2][3] We recently began studying Phycomyces blakesleeanus (Mucoraceae), which is a fungal producer of -carotene (provitamin A), riboflavine (vitamin B 2 ), pyridoxine (vitamin B 6 ), ergosterol (provitamin D 2 ), biotin, and nicotinic acid. 4,5 Therefore, oil from Phycomyces could be an interesting alimentary vitamin complement, if it were proven to be free of mycotoxins. We have identified more than forty nontoxic compounds among the acidic metabolites from P. blakesleeanus 6 and are now working on neutral metabolites. In the mycelium of P. blakesleeanus (NRRL1555 wild strain) we have found eleven sterols previously unreported in Phycomyces. These include the new natural sterols (1-3; Chart 1) with a 19-norergostane skeleton and an aromatic B ring. Previous studies of sterols from Phycomyces at the University College of Wales yielded a number of new sterols (4-13) and certain aspects of fungal ergosterol biosynthesis were resolved. 7-11 However, some sterols present in the fungus were not identified. 9 Results and DiscussionSterol and triterpene mixtures isolated from P. blakesleeanus were subjected to semipreparative HPLC. Fractions obtained were studied by NMR spectroscopy and aliquots were treated with N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) to form TMS derivatives for analysis by GC-MS. The sterol ester mixture was saponified, and the nonsaponifiable fraction was analyzed as described above. Results are shown in Table 1. Proportions are only approximate because they were determined from the area of the gas chromatogram peaks, based on total ion current response data. TMS-ethers of sterols were used for GC-MS analysis, instead of free sterols, because the former have better chromatographic properties and afford highly characteristic modes of fragmentation from which structural details may be inferred. 12 In the mass spectrum of 1, as the TMS-ether, the molecular ion was consistent with the TMS derivative of a sterol with the molecular formula C 27 H 40 O, containing four double bonds. The fragment ions [M -TMSOH -C 9 H 17 ] + , [M -TMSOH -C 6 H 11 ] + , and [M -(C 6 H 11 + H)] + indicated a side chain with nine carbon atoms and a double bond. Thus, 1 must possess a nucleus with three double bonds and ...

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Section: Resultsmentioning

confidence: 85%

Phycomysterols and Other Sterols from the Fungus Phycomyces blakesleeanus

Oltra

et al. 1998

J. Nat. Prod.

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“…Compounds 2 and 3 were obtained as a mixture, which were identified as (24S)-3b-hydroxy-24-ethylcholest-5-en-7-one and (24R)-3b-hydroxy-24-ethylcholest-5-en-7-one by direct comparison of their spectral data with those reported in the literature. [9][10][11] Presence of these compounds in this plant is reported for the first time herein.…”

Section: -8)mentioning

confidence: 70%

A Novel Iridoid from Boschniakia rossica

Yim

Kim

Liu

et al. 2004

CHEMICAL & PHARMACEUTICAL BULLETIN

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Boschniakia rossica FEDTSCH. et FLEROV (Orobanchaceae) is a parasitic plant grown on the roots of Alnus maximowiczii CALLIER (Betulaceae). Although its dried herb has been traditionally used as a tonic medicine in China, Korea and Japan, the tonic principle has not been yet described. It also attracts Felidae animals, and two compounds, boschniakine and boschnialactone, were isolated from this plant as being responsible for this activity.1) Some iridoids and phenylpropanoids were isolated from B. rossica in the previous studies.

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“…The stereochemistry of the C-24 methyl was assigned as S, based on the 1 H-NMR shifts of 26 and 27 methyls. 37,38) Thus the structure of the sterol 4 was established as (24S)-ergost-5-en-3b,7b-diol. The 7a-and 24R-isomers were reported earlier.…”

Section: )mentioning

confidence: 99%

New Sphingolipids and a Sterol from a Lobophytum Species of the Indian Ocean

Muralidhar¹,

Kumar²,

Krishna³

et al. 2005

CHEMICAL & PHARMACEUTICAL BULLETIN

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As part of our continuous search for bioactive metabolites from marine organisms, [2][3][4][5][6] we have investigated a soft coral species belonging to the genus Lobophytum collected from the Indian Ocean. Earlier studies of the genus Lobophytum led to the isolation of several sesquiterpenoids, cembrane and lobane diterpenes, sterols and sphingolipids. 7,8) Several compounds from this genus showed cytotoxic, [9][10][11] anti-HIV, 12) antibacterial, 13) and ichthyotoxic [14][15][16][17] activities. In this paper we report the isolation and structural elucidation of three new sphingolipids and a sterol along with cytotoxic activity of a known sphingolipid isolated from the organism.Sphingolipids exist widely in the eukaryotic cell membranes of both terrestrial and marine organisms.18) Sphingolipids attracted much attention in recent years due to their involvement in various cellular processes including cell growth, survival, differentiation, and adhesion. 19,20) Results and DiscussionRepeated column chromatography of EtOAc solubles of the methanolic extract of the organism followed by purification by medium pressure liquid chromatography (MPLC) afforded compounds 1-5 as colourless solids. The IR spectra of 1-3 suggested the presence of hydroxyl and amide groups while the UV spectra had no characteristic signals above 210 nm. Close examination of 1 H-and 13 C-NMR spectra of 1-3 (Table 1) revealed the presence of NH, carbonyl, end methyls and long aliphatic chain suggesting sphingolipid skeleton. . The stereochemistries at C-2, C-3 and C-2Ј were assigned 2S, 3R and 2ЈR by comparing the NMR and optical rotation data with those of natural and synthetic sphingolipids. [24][25][26][27] The geometry of the double bonds was taken as trans (4E,8E) on the basis of large coupling constants (15.3, 15.0 Hz). Chemical investigation of a soft coral species of the genus Lobophytum has resulted in the isolation of three new sphingolipids- (2S,3S,4R)-2-nonadecanoylamino-octadecane-1,3,4-triol (1), (2S,3R,4E,8E)

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The 220 MHz NMR spectra of phytosterols

Cited by 367 publications

References 22 publications

Phycomysterols and Other Sterols from the Fungus Phycomyces blakesleeanus

Phycomysterols and Other Sterols from the Fungus Phycomyces blakesleeanus

A Novel Iridoid from Boschniakia rossica

New Sphingolipids and a Sterol from a Lobophytum Species of the Indian Ocean

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