4α-methylergosta-8,24(28)-dien-3β-ol,a minor sterol in the seed of horse chestnut

From ripe horse chestnut seed the 4α-methyl sterol fraction was isolated representing 4.5% of the unsaponifiable matter, i.e. 3 mg% of the seed. This fraction was investigated by capillary GC and combined GC-MS. It contains at least 12 components, of which 5 were identified as: obtusifoliol 4α-methylergosta-8,24(28)-dien-3β-ol, gramisterol, cycloeucalenol and citrostadienol. The distribution of these five 4α-methyl sterols in the seed was also determined and they represent about 90% of the investigated fraction. 4α-Methylergosta-8,24(28)-dien-3β-ol up to now been found in higher plants only in traces, while in this fraction it was found in the amount of about 5%.     

4alpha-methyl-24beta-ethyl-5alpha-cholesta-14,25-dien-3beta-ol and 24beta-ethylcholesta-5, 9(11), 22E-trien-3beta-ol,sterols from Clerodendrum inerme

From the aerial parts of Clerodendrum inerme, two new sterols (4alpha-methyl-24beta-ethyl-5alpha-cholesta-14, 25-dien-3beta-ol and 24beta-ethylcholesta-5, 9(11), 22E-trien-3beta-ol) and a new aliphatic ketone (11-pentacosanone) were isolated together with another known aliphatic ketone (6-nonacosanone) and a diterpene (clerodermic acid). The structure elucidations were based on analyses of physical and spectroscopic data.     

Characterization of the structure of a 4-methyl-delta 8,24-cholestadien-3 beta-ol isolated from rat skin

A new sterol has been isolated from the skin of rats treated with triparanol. Its chromatographic behavior on silicic acid-Celite columns and in gas-liquid chromatographic systems indicated it to be a 4-methyl-Delta(8,24)-cholestadien-3beta-ol. The specific rotation, the delayed color reaction with Liebermann-Burchard reagent, and the nuclear magnetic resonance (NMR) data support the Delta(8(9))-unsaturation. Previous workers have shown that triparanol treatment results in an accumulation of Delta(24)-unsaturated sterols in animal tissues. Consonant with this observation, the infrared, NMR, and mass spectrometric data confirm the presence of a C-24(25) unsaturated side chain in this sterol.     

Accumulation of 14 alpha-methylergosta-8,24(28)-dien-3 beta,6 alpha-diol in 14 alpha-demethylation mutants of Candida albicans: genetic evidence for the involvement of 5-desaturase

14 alpha-Demethylation mutants of the fungus Candida albicans have been shown to accumulate 14 alpha-methylergosta-8,24(28)-dien-3 beta,6 alpha-diol. A derivative from one of these mutants (KD4900) that does not form this 6 alpha-hydroxylated sterol but is still defective in 14 alpha-demethylation (KD4950) was obtained. Mutational restitution of 14 alpha-demethylation capacity to this derivative resulted in the formation of the 5,6-saturated sterol ergosta-7,22-dien-3 beta-ol as the major product, clearly indicating that 5-desaturase deficiency exists in this demethylation-proficient revertant (KD4952). This implies that its parent, KD4950, which has lost the ability to form the hydroxylated sterol, also is deficient in 5-desaturation. We infer from the results that 5-desaturase is responsible for the formation of the hydroxylated sterol. However, it is unclear whether the hydroxylation represents a genuine step of the normal 5-desaturation reaction.     

Nematotoxicity of Marasmius oreades agglutinin (MOA) depends on glycolipid binding and cysteine protease activity

Fruiting body lectins have been proposed to act as effector proteins in the defense of fungi against parasites and predators. The Marasmius oreades agglutinin (MOA) is a Galα1,3Gal/GalNAc-specific lectin from the fairy ring mushroom that consists of an N-terminal ricin B-type lectin domain and a C-terminal dimerization domain. The latter domain shows structural similarity to catalytically active proteins, suggesting that, in addition to its carbohydrate-binding activity, MOA has an enzymatic function. Here, we demonstrate toxicity of MOA toward the model nematode Caenorhabditis elegans. This toxicity depends on binding of MOA to glycosphingolipids of the worm via its lectin domain. We show further that MOA has cysteine protease activity and demonstrate a critical role of this catalytic function in MOA-mediated nematotoxicity. The proteolytic activity of MOA was dependent on high Ca(2+) concentrations and favored by slightly alkaline pH, suggesting that these conditions trigger activation of the toxin at the target location. Our results suggest that MOA is a fungal toxin with intriguing similarities to bacterial binary toxins and has a protective function against fungivorous soil nematodes.     

Chemical synthesis, spectral properties, and chromatography of 4alpha-methyl and 4beta-methyl isomers of (24R)-24-ethyl-5alpha-cholestan-3beta-ol and (24S)-24-ethyl-cholesta-5,22-dien-3beta-ol.

Described herein are chemical syntheses of the following compounds: 4-methyl-(24S)-24-ethyl-cholesta-4,22-dien-3-one, 4,4-dimethyl-(24S)-24-ethyl-cholesta-5,22-dien-3-one, 4beta-methyl-(24R)-24-ethyl-5alpha-cholestan-3beta-ol, 4alpha-methyl-(24R)-24-ethyl-5alpha-cholestan-3beta-ol, 4alpha-methyl-(24S)-24-ethyl-5alpha-cholest-22-en-3beta-ol, 4-methyl-6beta-bromo-(24S)-24-ethyl-cholesta-4,22-dien-3-one, 4alpha-methyl-(24S)-24-ethyl-cholesta-5,22-dien-3beta-ol, 4alpha,5alpha-epoxy-(24S)-24-ethyl-cholesta-4,22-dien-3beta-yl acetate, 4beta-methyl-(24S)-24-ethyl-cholest-22-en-3beta,5alpha-diol, 4beta-methyl-5alpha-hydroxy-(24S)-24-ethyl-cholest-22-en-3beta-yl acetate, 4beta-methyl-(24S)-24-ethyl-cholesta-5,22-dien-3beta-yl acetate and 4beta-methyl-(24S)-24-ethyl-cholesta-5,22-dien-3beta-ol. Chromatographic, nuclear magnetic resonance, and mass spectral data are presented for the compounds under consideration.     

Synthesis of iodine-131 labeled 6 beta-iodomethyl-19-norsitost-5(10)-en-3 beta-ol and 19-iodositost-5-en-3 beta-ol for adrenal imaging.

6 BETA-Iodomethyl-19-norsitost-5(10)-en-3 beta-ol (V) was synthesized by homoallylic rearrangement of 19-iodositost-5-en-3 beta-ol (IV), which was obtained by the hydrolysis of 19-iodositost-5-en-3 beta-ol acetate (III) derived from the displacement of sitost-5-ene-3 beta, 19-diol 3-acetate 19-p-toluenesulfonate (I) with sodium iodide in isopropanol. The radioiodinated IV and V were prepared by isotope exchange with sodium iodide-I-131.     

Erinacol (cyatha-3,12-dien-14beta-ol) and 11-O-acetylcyathin A3, new cyathane metabolites from an erinacine Q-producing Hericium erinaceum

In our search for new cyathane metabolites related to the biosynthesis of erinacine Q in Hericium erinaceum, we isolated a novel cyatha-3,12-dien-14beta-ol named erinacol together with known 11-O-acetylcyathatriol (the erinacine Q aglycon) and new metabolite 11-O-acetylcyathin A(3) from the mycelial extract. The structure of each compound was determined by spectral methods. Possible biosynthetic relationships of these metabolites are discussed from their structural features.     

Isolation of Lanosta-8,25-dien-3β-ol from the fungus Fomes Fastuosus

A new lanostane triterpene has been isolated from the fungus Fomes fastuosus which causes wood-rotting of Emblica officinalis. The compound is assigned the structure lanosta-8,25-dien-3β-ol on the basis of spectral data and correlation with lanosterol.     

Total synthesis of heterocyclic steroids, part I, synthesis of (+/-)-A-nor-3-thiaestra-1,5(10)-dien-17 beta-ol.

Total synthesis of (±)-A-nor-3-thiaestra-1,5(10)-dien-17β-ol was achieved starting from 4-o xo-4,5,6,7-tetrahydrobenzothiophene.     

Foliar application of the triterpene derivative 24-methylen-elemo-lanosta-8,24-dien-3-one alleviates salt toxicity in grapevine

This work focused on the effect triterpene derivative 24-methylen-elemo-lanosta-8,24-dien-3-one (F3) on the induction of salt stress tolerance of the Moroccan grapevine cv. “Doukkali”. Hardwood cuttings of the grapevine from a homogeneous plant material collected in the field were grown in hydroponic medium under different salt concentrations and treated with 50 or 100 µg ml^?1 of F3. Salt stress affected several physiological and biochemical parameters including relative water content, chlorophyll a and b content, peroxidase, and polyphenol oxidase activities, which decreased along with time. Meanwhile, proline, proteins, soluble sugars, H₂O₂, and carotenoid content, as well as phenolic compound content increased, suggesting an evidence of tolerance of this local variety to salinity. An exogenous supply of the triterpenic product increased all these parameters under normal conditions. In addition, F3 at low dose was found to be successful in lowering Na⁺ content and alleviating the inhibitory effects of salt stress on relative water content as well as on chlorophyll a and b.     

Characterization of the recognition of blood group B trisaccharide derivatives by the lectin from Marasmius oreades using frontal affinity chromatography-mass spectrometry

A novel lectin from the mushroom Marasmius oreades (MOA) has been shown to bind to human blood group B oligosaccharides [1]. In the present work we examine the binding of a series of analogues of the blood group B-trisaccharide, Gal(1-3)[Fuc(1-2)]Gal-OR (1, R = (CH₂)₈COOMe). MOA was biotinylated and immobilized on a micro column (9.8 L) for evaluation by Frontal Affinity Chromatography-Mass Spectrometry (FAC-MS) [2]. The trisaccharide 1 was found to be the epitope needed for maximum recognition (K _d = 3.6 M). A series of synthetic deoxygenated and O-methylated analogues of the B-trisaccharide (R = OMe) were then screened against the lectin, and the key structural elements for binding were determined. OH-4 of the -Gal residue and OH-2 of the -Gal residue were found to be critical for recognition. The FAC-MS technique also proved powerful in evaluating mixtures of compounds. Since the solution NMR structure and crystal structure of the B-trisaccharide are known [3], we propose the specific surface of the trisaccharide that is recognized by the lectin. Published in 2003.     

Studies on Galalpha3-binding proteins: comparison of the glycosphingolipid binding specificities of Marasmius oreades lectin and Euonymus europaeus lectin

The carbohydrate binding preferences of the Galalpha3Galbeta4 GlcNAc-binding lectins from Marasmius oreades and Euonymus europaeus were examined by binding to glycosphingolipids on thin-layer chromatograms and in microtiter wells. The M. oreades lectin bound to Galalpha3-terminated glycosphingolipids with a preference for type 2 chains. The B6 type 2 glycosphingolipid (Galalpha3[Fucalpha2]Galbeta4GlcNAcbeta3Galbeta4Glcbeta1Cer) was preferred over the B5 glycosphingolipid (Galalpha3Galbeta4GlcNAcbeta3Galbeta4Glcbeta1Cer), suggesting that the alpha2-linked Fuc is accommodated in the carbohydrate binding site, providing additional interactions. The lectin from E. europaeus had broader binding specificity. The B6 type 2 glycosphingolipid was the best ligand also for this lectin, but binding to the B6 type 1 glycosphingolipid (Galalpha3[Fucalpha2]Galbeta3GlcNAcbeta3Galbeta4Glcbeta1Cer) was also obtained. Furthermore, the H5 type 2 glycosphingolipid (Fucalpha2Galbeta4GlcNAcbeta3Galbeta4Glcbeta1Cer), devoid of a terminal alpha3-linked Gal, was preferred over the the B5 glycosphingolipid, demonstrating a significant contribution to the binding affinity by the alpha2-linked Fuc. The more tolerant nature of the lectin from E. europaeus was also demonstrated by the binding of this lectin, but not the M. oreades lectin, to the x2 glycosphingolipid (GalNAcbeta3Galbeta4GlcNAcbeta3Galbeta4Glcbeta1Cer) and GlcNAcbeta3Galbeta4GlcNAcbeta3Galbeta4Glcbeta1Cer. The A6 type 2 glycosphingolipid (GalNAcalpha3[Fucalpha2]Galbeta4GlcNAcbeta3Galbeta4Glcbeta1Cer) and GalNAcalpha3Galbeta4GlcNAcbeta3Galbeta4Glcbeta1-Cer were not recognized by the lectins despite the interaction with B6 type 2 glycosphingolipid and the B5 glycosphingolipid. These observations are explained by the absolute requirement of a free hydroxyl in the 2-position of Galalpha3 and that the E. europaea lectin can accommodate a GlcNAc acetamido moiety close to this position by reorienting the terminal sugar, whereas the M. oreades lectin cannot.     

Stigmasta-7,E-24(28)-dien-3β-ol from Bryonia dioica roots

Stigmasta-7,E-24(28)-dien 3β-ol was isolated from the roots of Bryonia dioica; it has been previously synthesised, but never found in the plant kingdom. The stereochemistry of the 24(28) double bond was unambiguously proved by high resolution (250 MHz) ¹H NMR.