Neutral diterpenoids of oleoresins of five species of conifers of Transcarpathia

The compositions of the neutral diterpenoids of the oleoresins of five species of conifers growing in the Transcarpathia have been studied. It has been found that the oleoresins ofAbies alba M.,Larix decidua M., andPicea excelsa L. contain more than 50% of neutral diterpenoids. The group and qualitative compositions of the oxygen-containing diterpenoids have been determined. In the oleoresins ofAbies alba,Picea excelsa, andPicea abies tertiary alcohols — cis-abienol and isocembrol — predominate, while inLarix decidua the main component is the hydroxy ester larixyl acetate. Primary alcohols related to the resin acids have been found in all the oleoresins investigated. Features of the distribution of diterpenoids according to the species of conifers have been revealed. The results obtained are necessary for the chemotaxonomy of conifers of the family Pinceae.     

Alkaloids of Rauwolfia species growing in Vietnam

Reserpine, ajmaline, serpentine, ajmalicine, isoreserpiline, and other alkaloids have been isolated from the roots ofRauwolfia cambodiana Pierre ex Pitard,R. verticillata Baill. andR. serpentina Benth.R. vomitoria Afz. was the richest in alkaloids.     

Gas-chromatographic determination of the composition of the volatile components of the oleoresins of some species of conifers

Using the method of analytical GLC in a glass capillary column, the compositions have been studied of the volatile fractions of the oleoresins of five species of conifers:Larix decidua,Pinus strobus,Pinus mugo,Picea excelsa, andPinus abies. In the oleoresins 21 monoterpene and 22 sesquiterpene compounds were identified from their relative retention times and with the aid of additives. The main components of the volatile fractions of the oleoresins were - and -pinenes and 3-carene among the monoterpenes, and longifolene caryophyllene, - and -cadinenes and -murolene among the sesquiterpene compounds. The quantitative analysis of the fractions was carried out by the method of internal normalization from averaged correlation coefficients.Institute of Organic Chemistry, Siberian Branch, Academy of Sciences of the USSR, Novosibirsk. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 629–632, September–October, 1990.     

Lipopolysaccharides of marine blue-green algae

The lipopolysaccharides (LPSs) have been isolated from two blue-green algae,Oscillatoria hilderbrandtii andNostoc sp. by the method of phenol-water extraction. The LPSs contain polysaccharide and lipid components. The polysaccharide fraction fromO. hildebrandtii consists predominantly of 1,3-bound rhamnose residues with a substituent in the second position. The rhamnose residues in the polysaccharide fraction ofNostoc are connected by 1,3- and 1,2-glycosidic bonds. The lipid components of the LPSs fromO. hilderbrandtii andNostoc consist of palmitic and steric acids, with glucosamine and glucose.     

Size-dependent core-level spectroscopy of free neutral clusters

Studies of the electronic and geometric structure of free clusters are presented to highlight the application of core-level spectroscopy using synchrotron radiation to cluster physics. The study of electronic structure deals with the excitation of the C 1s electron to the Rydberg states of the molecule in CH₄ clusters and demonstrates the gradual evolution of the surface and bulk-specific spectral features with cluster size. A second study investigates the K-edge excitations in Ne clusters and is concerned with extracting structural information from the X-rays Absorption Near-Edge Structure (XANES).     

Pentaketide metabolites of mutants and the biosynthesis of melanin inVerticillium tricorpus

From mutants of the fungusVerticillium tricorpus Isaac., having various genetic blocks in the biosynthesis of melanin, we have isolated and identified scytalone, flaviolin, 3,3′-biflavinolin, 2-hydroxyjuglone, vermelone, and 1,8-dihydroxynaphthalene, which, in combination with the results of complementation analysis, has enabled the main stages of the biosynthesis of melanin inV. tricorpus to be established. The results on the inhibition of the biosynthesis of melanin by tricyclazole in natural isolates ofV. tricorpus indicates that the initital stages of the biosynthesis of melanin inV. tricorpus up to the formation of 1,3,8-trihydroxynaphthalene are identical with those ofVerticillium dahliae.     

Lipids of the fruit ofAcanthopanax sessiliflorus

In the lipids of the seeds and pericarp of the introduced speciesAcanthopanax sessiliflorus (Rupr. et Maxim.) Seem (familyAraliaceae), 23 classes of compounds have been detected, of which 19 have been identified. Sixteen of the classes have been studied. The lipids of the pericarp contain a more complex set of components than the seeds. Hydroxyacyldiacylglycerides, fatty acid methyl esters, and a complex group of pthalicacidesters have been detected in the familyAraliaceae for the first time. The fatty acid compositions of the seed and pericarp lipids are characterized by a high level of petroselinic acid.     

Glycosides of marine invertebrates. VIII. Steroid glycosides of the holothurianIsostichopus badionotus

The steroid glycoside fraction ofIsostichopus badionotus, consisting of a mixture of D-xylosides of steroid alcohols, has been isolated by column chromatography on silica gel. The mixture of aglycones obtained after acid hydrolysis was separated with the aid of argentation chromatography into several fractions. GLC-MS analysis, and also the use of IR and¹³C NMR spectroscopy has shown that the steroid glycosides ofI. badionotus are xylosides of Δ⁰-, Δ⁷-, Δ²²-, and Δ^7.22-, C₂₇-, C₂₈-, and C₂₉-steroids of the cholestane series.     

Structure of ergolide

The epigeal part ofErigeron khorassanicus Boiss. has yielded a new sesquiterpene lactone of the pseudoguaiane type — ergolide C₁₇H₂₂O₅, mp 179–180°C (ethanol) [α] _D ²⁰ +123° (c 4.88; ethanol). On the basis of chemical transformations and spectral characteristics, its structure and configuration have been established as 6-acetoxy-4-oxo-1,7αH,6,8,10βH-pseudoguai-11(13)-en-8,12-olide.     

Preparation and Characterization of the Solid Inclusion Compounds of α-, β-Cyclodextrin with Phenylalanine (D-, L- and DL-Phe) and Tryptophan (D-, L- and DL-Trp)

The solid cyclodextrin (α-, β-CD) inclusion compounds of phenylalanine (D-, L- and DL-Phe) and tryptophan (D-, L-?and DL-Trp) were prepared and the stoichiometry of host and guest in the supermolecules was determined to be 1:1 based on elemental analyses. β-CD formed inclusion compounds with α-aromatic amino acid (α-AAA) in higher yield in contradistinction to α-CD. The yields of the α- or β-CD inclusion compounds of a pair of optical isomers of chiral aromatic amino acids and their racemic modification decreased in the order L->DL->D-form. The complexation between CD and α-AAA caused a change in shape, location and diffracted intensity of the X-ray diffraction peaks of both host and guest. The decomposition temperature of the inclusion compounds was not only slightly higher than that of a pure host but also remarkably higher than that of a pure guest. Upon inclusion the signals of CD protons inside the cavity shifted to upfield while those of the protons outside the cavity had only smaller changes, and the proton signals of the aromatic ring of guest shifted to a certain extent. The chemical shift changes of 4-H and 5-H located in small end side of cavity were a bit bigger than those of 2-H and 3-H located in large one, suggesting that aromatic ring of a guest molecule within a host cavity might be kept near small end side of?cavity. An ESI-MS experiment has proved the formation and stability of the 1:1 CD inclusion compounds of α-AAA in aqueous solution.     

Pheromones of insects and their analogs

From cyclohexene and caproaldehyde, using ozonolysis and the Knoevenagel reaction, we have synthesized hexadeca-7Z,11E-dien-l-yl acetate — the sex pheromone ofSitotroga cerealella and a component of the sex pheromone ofPectinophora gossypiella.     

Isoform specific gene auto-regulation via miRNAs: a case study on miR-128b and ARPP-21

In this study, we investigate whether miRNAs located within “host” protein-coding genes may regulate the expression of their host genes. We find that 43 of 174 miRNAs encoded within RefSeq genes are predicted to target their host genes. Statistical analysis of this phenomenon suggests that gene auto-regulation via miRNAs may be under positive selective pressure. Our analysis also indicates that several of the 43 miRNAs have a much lower expectation of targeting their host genes by chance than others. Among these examples, we identify miR-128b:ARPP-21 (cyclic AMP-regulated phosphoprotein, 21 kD) as a case in which both the miRNA and the target site are also evolutionarily conserved. We provide experimental support for this miRNA:target interaction via reporter silencing assays, and present evidence that this isoform-specific gene auto-regulation has been preserved in vertebrate species in order to prevent detrimental consequences of ARPP-21 over-expression in brain.     

The application of immobilized α-L-rhamnosidase andL-rhamnosedehydrogenase in the analysis ofL-rhamnose and α-L-rhamnosides

A highly sensitive and specific enzymatic assay for the quantitative determination of α-L-rhamnosides employing naringinase (an enzyme complex consisting of α-L-rhamnosidase and β-L-glucosidase) andL-rhamnose dehydrogenase is described. The test can be carried out in the presence of other glycosides or sugars and deoxysugars. Even compounds having very low solubility can be assayed by this procedure.     

Polysaccharides of iridaceae V. Characterization of the neutral fraction of the water soluble polysaccharide from Juno drepanophylla

From the WSPS-I of the bulbs with roots ofJuno drepanophylla, 15 fractions have been isolated by fractionation on DEAE-cellulose. Fractions 1 and 2 together made up 53% of the total weight of the fractions. Fraction 1 proved to be homogeneous on ultracentrifugation, on passage through Sepharose-4B, and on high-pressure LC. The results of the analysis of the methylated product of fraction 1 differed little from those for the initial polysaccharide.     

The pivotal role of copper(II) in the enantiorecognition of tryptophan and histidine by gold nanoparticles

Stereoselective amino acid analysis has increasingly moved into the scope of interest of the scientific community. In this work, we report a study on the chiral recognition of d,l-Trp and d,l-His using l-Cys-capped gold nanoparticles (AuNPs) and copper(II) ion. In the l-Cys-capped AuNPs, the thiol group of the amino acid interacts with AuNPs through the formation of Au–S bond, whereas the α-amino and α-carboxyl groups of the surface-confined cysteine can coordinate the copper(II) ion, which in turn, binds the l- or d-amino acid present in solution forming diastereoisomeric complexes. The resulting systems have been characterized by UV–Vis spectra and dynamic light scattering measurements, obtaining different results for l- and d-Trp, as well as for l- and d-His. The knowledge of the solution equilibria of the investigated systems allowed us to accurately calculate in advance the concentrations of the species present in solution and to optimize the system performances, highlighting the pivotal role of copper(II) ion in the enantiodiscrimination processes.     

Lipids of the biomass ofRuta graveolens,grownin vivo andin vitro

A lower content of chlorophylls, phospholipids, and linolenic acid and a higher content of rutin, carotenoids, and xanthophylls in the biomass ofRuta graveolens L. obtainedin vitro has been found as compared with these indices from the epigeal part of the plant grownin vivo.     

The mannan formed by the yeastBullera tsugae

The structure of an extracellular mannan formed by the yeastBullera tsugae has been studied. It has been shown that the repeating unit of this polysaccharide contains β-(1→3)- and β-(1→4)-bound D-mannopyranose residues in equimolar ratio. A comparison has been made of the polymer under investigation with the extracellular mannan from a yeast of the genusRhodotorula.     

Synthesis of N-glycyl-β-glycopyranosyl amines,derivatives of natural oligosaccharides — glucose analogs of Lex antigen

Treatment of the natural tri-, tetra-, and pentasaccharides, β-d-Galp-(1→4)-[α-l-Fucp-(1→3)]-d-Glcp, α-l-Fucp-(1→2)-β-d-Galp-(1→4)-[α-l-Fucp-(1→3)]-d-Glcp, and α-l-Fucp-(1→2)-[α-d-GalNAcp-(1→3)]-β-d-Galp-(1→4)-[α-l-Fucp-(1→3)]-d-Glcp, which are glucose analogs of Le^x, with ammonium carbamate in aqueous methanol gave the corresponding β-glycopyranosyl amines. After their N-acylation with N-Z-glycine N-hydroxysuccinimidyl ester (Z is benzyloxycarbonyl) with subsequent hydrogenolytic removal of Z-group, corresponding N-glycyl-β-glycopyranosyl amines were obtained in yields up to 70%.     

Steroids of the spirostand and furostan series from plants of the genusAllium. II. The structure of alliospiroside B fromAllium cepa

A new steroid glycoside — alliospiroside B (I) — has been isolated from the collective fruit ofAllium cepa L. On the basis of chemical transformations and with the aid of physicochemical measurements it has been established that compound (I) has the structure of (25S)spirost-5-ene-1β,3β-diol 1-O-[O-α-L-rhamnopyranosyl-(1 → 2)-β-D-galactopyranoside. Compound (I) C₃₉H₆₂O₃, mp 200–202°C (from ethanol). [α] _D ²⁰ ?110.9±2° (c 1.01; pyridine) was obtained by extracting the collective fruit ofA. cepa with ethanol folowed by the column chromatographic separation of the combined glycosides on silica gel. The acid hydrolysis of (I) gave (25S)-ruscogenin (II), C₂₇H₄₂O₄, mp 189–191°C, [α] _D ²³ ?104.1±2° (c 0.98; pyridine). The¹H and¹³C NMR spectra are given for both compounds and the IR spectrum for compound (I).     

Cerebrosides of the Far Eastern sponge Hymeniacidon assimilis

Cerebrosides have been isolated from chloroform-ethanol extract of the spongeHymeniacidon assimilis. Their structures have been established with the aid of¹H NMR spectroscopy, acid hydrolysis, and ozonolysis as the β-galactosides of the C₁₆-, C₁₇-, and C₁₈-erythro-Δ⁴-sphingenines of normal, iso, and anteiso structures acylated in the amino groups with C₂₁-, C₂₂-, and C₂₃-α-hydroxy acids. The cerebrosides fromH. assimilis differ in structure from the corresponding compounds isolated previously from sponges.