Identification of 2-O (indole-3-acetyl)-D-glucopyranose, 4-O-(indole-3-acetyl)-D-glucopyranose and 6-O-(indole-3-acetyl)-D-glucopyranose from kernels of Zea mays by gas-liquid chromatography-mass spectrometry

New esters of indole-3-acetic acid and d-glucose have been isolated from mature sweet-corn kernels of Zea mays. The esters were resolved by t.l.c. into two fractions having R_F values distinct from that of authentic 1-O-(indole-3-acetyl)-β-d-glucopyranose. Analysis of the trimethylsilyl ethers of the two fractions by combined gas-liquid chromatography-mass spectrometry (g.l.c.-m.s.) showed that the esters have a free carbonyl group. Labeling of the carbonyl carbon atom with an O-methyloxime group, and analysis of the O-trimethylsilyl O-methyloxime derivatives by g.l.c.-m.s. permitted the new compounds to be identified as a mixture of 2-O-(indole-3-acetyl)-d-glucopyranose, 4-O-(indole-3-acetyl)-d-glucopyranose, and 6-O-(indole-3-acetyl)-d-glucopyranose.     

Photochemical oxidation of partially protected derivatives of α-d-glucofuranose and β-d-fructofuranose

An improved procedure for the preparation of 1,2-O-isopropylidene-β-d-fructofuranose and its 6-pyruvoylation is described. Photolysis of this ester in benzene furnished 5,6-O-isopropylidene-β-d-lyxo-5-ulofuranose, characterised as the O-methyloxime diacetate. Similary, photochemical oxidation of 1 1,2-O-isopropylidene-6-O-pyruvoyl-α-d-glucofuranose gave 1,2-O-isopropylidene-α-d-lgluco-hexodialo1,4:6,3-difuranose in excellent yield.     

Isomerization of 1-O-Indol-3-Ylacetyl-β-d-Glucose : Enzymatic Hydrolysis of 1-O, 4-O, and 6-O-Indol-3-YlacetyL-β-d-Glucose and the Enzymatic Synthesis of Indole-3-Acetyl Glycerol by a Hormone Metabolizing Complex

The first compound in the series of reactions leading to the ester conjugates of indole-3-acetic acid (IAA) in kernels of Zea mays sweet corn is the acyl alkyl acetal, 1-O-indol-3-ylacetyl-β-d-glucose (1-O-IAGlu). The enzyme catalyzing the synthesis of this compound is UDP-glucose:indol-3-ylacetate glucosyl-transferase (IAGlu synthase). The IAA moiety of the high energy compound 1-O-IAGlu may be enzymatically transferred to myo-inositol or to glycerol or the 1-O-IAGlu may be enzymatically hydrolyzed. Alternatively, nonenzymatic acyl migration may occur to yield the 2-O, 4-O, and 6-O esters of IAA and glucose. The 4-O and 6-O esters may then be enzymatically hydrolyzed to yield free IAA and glucose. This work reports new enzymatic activities, the transfer of IAA from 1-O-IAGlu to glycerol, and the enzymecatalyzed hydrolysis of 4-O- and 6-O-IAGlu. Data is also presented on the rate of non-enzymatic acyl migration of IAA from the 1-O to the 4-O and 6-O positions of glucose. We also report that enzymes catalyzing the synthesis of 1-O-IAGlu and the hydrolysis of 1-O, 4-O, and 6-O-IAGlu fractionate as a hormone metabolizing complex. The association of synthetic and hydrolytic capabilities in enzymes which cofractionate may have physiological significance.     

Cyanosalvianin, a supramolecular blue metalloanthocyanin, from petals of Salvia uliginosa

A metalloanthocyanin, cyanosalvianin, was found in blue petals of Salvia uliginosa. Cyanosalvianin consisted of 3-O-(6-O-p-coumaroylglucopyranosyl)-5-O-(4-O-acetyl-6-O-malonylglucopyranosyl) delphinidin, 7,4′-di-O-glucopyranosylapigenin and magnesium ion. We reproduced the same blue color as the petals by mixing the three components together. An ESI-MS measurement gave a molecular weight of 9014 indicating the composition of cyanosalvianin to be six molecules of the anthocyanin component, six molecules of the flavone component and two magnesium ions. The special arrangement of the organic components in cyanosalvianin was analyzed by CD and 2D-NMR spectroscopy. It was clarified that cyanosalvianin has a similar structure to that of commelinin, a metalloanthocyanin isolated from blue dayflower, Commelina communis.     

The use of 1-O-tosyl-d-glucopyranose derivatives in α-d-glucoside synthesis

1-O-Tosyl-d-glucopyranose derivatives having a nonparticipating benzyl group at O-2 have been shown to react rapidly in various solvents with low concentrations of alcohols, either methanol or methyl 2,3,4-tri-O-benzyl-α-d-glucopyranoside. The stereospecificity of the glucoside-forming reaction could be varied from 80% of β to 100% of α anomer by changing the solvent or modifying the substituents on the 1-O-tosyl-d-glucopyranose derivative. 2,3,4-Tri-O-benzyl-6-O-(N-phenylcarbamoyl)-1-O-tosyl-α-d-glucopyranose in diethyl ether gave a high yield of α-d-glucoside. Kinetic measurements of reaction with various alcohols (methanol, 2-propanol, and cyclohexanol) show a high rate even at low concentrations of alcohol, and give some insight into the reaction mechanism. The high rate and stereoselectivity of their reaction suggest that the 1-O-tosyl-d-glucopyranose derivatives may be used as reagents for oligosaccharide synthesis.     

Michael Heidelberger as a Carbohydrate Chemist

The deoxyaldaric acids corresponding in structure to the 3-deoxy-2-C-(hydroxymethyl)aldonic (isosaccharinic) acids have been identified as products of treatment of various carbohydrates with alkali and oxygen-alkali. The structures of the acids were determined from the mass spectra of their Me₃Si derivatives on the basis of previously known, specific fragmentation reactions. The g.l.c.-m.s. technique was used, and g.l.c. retention data are given. The identified species are 2-deoxy-3-C-(hydroxymethyl)tetraric, 3-deoxy-2-C-hydroxymethyl-erythro-pentaric, 3-deoxy-2-C-hydroxymethyl-threo-pentaric, 2-methyltartronic, 2-(2-hydroxyethyl)tartronic, and 2-(2,3-dihydroxypropyl)tartronic acids. Their formation from 4-O-substituted uronic and ulosonic acids is briefly discussed.     

Caffeic acid derivatives and further compounds from Espeletia barclayana Cuatrec. (Asteraceae,Espeletiinae)

This work describes the isolation of seven (1–7) secondary metabolites from Espeletia barclayana (Asteraceae, Espeletiinae) and their identification by spectroscopic (NMR) and spectrometric (MS) techniques. Ten (8–17) additional compounds were identified based on their retention times, high-resolution mass spectrometry data, and comparison with reference substances or data from literature. The systematic significance of some of the identified substances – the sesquiterpene lactone longipilin acetate, four caffeoylquinic acids and two tri-caffeoylaltraric acids – is discussed with the aim of providing insights into the complex relationships among Espeletiinae taxa and its closest relatives. Five of the isolated metabolites [5-O-(E)-caffeoylquinic acid (1), 1,3-di-O-(E)-caffeoylquinic acid (2), 1,5-di-O-(E)-caffeoylquinic acid (3), 3,4-di-O-(E)-caffeoylquinic acid (4) and 3-O-methylquercetin 7-O-β-glucopyranoside (7)] constitute new reports for the genus Espeletia and for the subtribe Espeletiinae. Chemical data suggest that Espeletiinae might have a closer relationship with Smallanthus than with Ichthyothere, i.e., the two genera suggested to be the sister groups of Espeletiinae based on molecular markers.     

Carbohydrates of the brown seaweeds : Part III. Desmarestia aculeata

Mannitol, sucrose, and laminitol have been isolated from ethanolic extracts of the brown seaweed Desmarestia aculeata and characterised, and rhamnose, sedoheptulose, glucose, fructose, and 2-O-methyl- and 3-O-methyl-fucose have been identified by their chromatographic mobilities and g.l.c. retention times. Laminarin, alginic acid, and “fucans” were isolated also and characterised. The laminarin contained 1.7% of mannitol end-groups, and the fucans a relatively high proportion of galactose which was present as end-group and (1→3)-linked units.     

Flower pigment composition of Crocus species and cultivars used for a chemotaxonomic investigation

A survey of floral anthocyanins and other flavonoids by analytical high-performance liquid chromatography (HPLC) was performed among 70 species and subspecies, 43 cultivars and six artificial hybrids of Crocus and the results were compared with taxonomical delimitations established by Mathew (The Crocus. B.T. Batsford Ltd, London, 1982).Nine anthocyanins were detected. The Crocus species and cultivars were placed into seven chemotypes according to their contents of 3,7-di-O-, 3,5-di-O-glucosides or 3-O-rutinosides of delphinidin and petunidin and to the presence of 3,7-di-O-malonyl-glucosides of petunidin and malvidin and delphinidin 3-O-glucoside-5-O-malonylglucoside. These malonated anthocyanins have only been found in Crocus and may be characteristic for this genus.The same 18 flavonoids were detected in every taxon. However, quantitative differences were noted and four chemotypes of Crocus were defined by their major contents of flavonoids. Six of the flavonoids appear to be unique for Crocus.The anthocyanin/flavonoid patterns of some of the taxa provide a valuable supplement to the taxonomy based on morphological and cytological patterns. Most chemotypes were represented in several series but the chemical data were useful in distinguishing different species. For all series except Series h the chemical data were very similar for all subspecies or accessions within a species, and chemotypes within a series were more similar than between series. However for six species, the analyses suggest that they should be further investigated using other methods, to evaluate their relations to other series.     

Galactose 6-O-Sulfotransferases Are Not Required for the Generation of Siglec-F Ligands in Leukocytes or Lung Tissue

Eosinophil accumulation is a characteristic feature of the immune response to parasitic worms and allergens. The cell surface carbohydrate-binding receptor Siglec-F is highly expressed on eosinophils and negatively regulates their accumulation during inflammation. Although endogenous ligands for Siglec-F have yet to be biochemically defined, binding studies using glycan arrays have implicated galactose 6-O-sulfate (Gal6S) as a partial recognition determinant for this receptor. Only two sulfotransferases are known to generate Gal6S, namely keratan sulfate galactose 6-O-sulfotransferase (KSGal6ST) and chondroitin 6-O-sulfotransferase 1 (C6ST-1). Here we use mice deficient in both KSGal6ST and C6ST-1 to determine whether these sulfotransferases are required for the generation of endogenous Siglec-F ligands. First, we characterize ligand expression on leukocyte populations and find that ligands are predominantly expressed on cell types also expressing Siglec-F, namely eosinophils, neutrophils, and alveolar macrophages. We also detect Siglec-F ligand activity in bronchoalveolar lavage fluid fractions containing polymeric secreted mucins, including MUC5B. Consistent with these observations, ligands in the lung increase dramatically during infection with the parasitic nematode, Nippostrongylus brasiliensis, which is known to induce eosinophil accumulation and mucus production. Surprisingly, Gal6S is undetectable in sialylated glycans from eosinophils and BAL fluid analyzed by mass spectrometry. Furthermore, none of the ligands we describe are diminished in mice lacking KSGal6ST and C6ST-1, indicating that neither of the known galactose 6-O-sulfotransferases is required for ligand synthesis. These results establish that ligands for Siglec-F are present on several cell types that are relevant during allergic lung inflammation and argue against the widely held view that Gal6S is critical for glycan recognition by this receptor.     

Glucosyloxy alkaloids from Pancratium biflorum

From fluids of flower stems and bulbs, and from extracts of roots of Pancratium biflorum, collected at different stages of growth, three new glucosyloxy alkaloids, viz. hordenine-4-O-β-d-glucoside, lycorine-1-O-β-d-glucoside and pseudolycorine-1-O-β-d-glucoside, have been isolated and characterized. Additionally, three proto alkaloids, β-phenethylamine, tyramine and hordenine, together with four true alkaloids, lycorine, pseudolycorine, pretazettine and tazettine, encountered before in other memebrs of the Amaryllidaceae, have now been isolated also from this species. Ontogenic variations of alkaloidal constituents have been observed. The ability of the alkaloidal constituents to complex with divalent metal ions and phytosterols has been examined with a view to evaluating their significance in plant biochemistry.     

New light labile linker for solid phase synthesis of 2'-O-acetalester oligonucleotides and applications to siRNA prodrug development

We report on the synthesis and properties of oligonucleotides containing 2′-O-(levulinic acid) and 2′-O-(amino acid) acetalesters. Given that esters serve as promoieties in several therapeutic prodrugs, we believe that these derivatives will have potential use as nucleic acid prodrugs. In addition, we report on the synthesis of a novel solid support with a photolabile linker that not only allows for the synthesis of oligonucleotides containing various 2′-O-acetalesters, but can be generally adopted to the synthesis of base-sensitive oligoribonucleotides. The release of oligonucleotides from this support is faster than with conventional linkers.     

Liquid chromatography–diode array detection–mass spectrometry for compositional analysis of low molecular weight heparins

Low molecular weight heparins (LMWHs) are important artificial preparations from heparin polysaccharide and are widely used as anticoagulant drugs. To analyze the structure and composition of LMWHs, identification and quantitation of their natural and modified building blocks are indispensable. We have established a novel reversed-phase high-performance liquid chromatography–diode array detection–electrospray ionization–mass spectrometry approach for compositional analysis of LMWHs. After being exhaustively digested and labeled with 2-aminoacridone, the structural motifs constructing LMWHs, including 17 components from dalteparin and 15 components from enoxaparin, were well separated, identified, and quantified. Besides the eight natural heparin disaccharides, many characteristic structures from dalteparin and enoxaparin, such as modified structures from the reducing end and nonreducing end, 3-O-sulfated tetrasaccharides, and trisaccharides, have been unambiguously identified based on their retention time and mass spectra. Compared with the traditional heparin compositional analysis methods, the approach described here is not only robust but also comprehensive because it is capable of identifying and quantifying nearly all components from lyase digests of LMWHs.     

Polyphenolic compounds in the fruits of Egyptian medicinal plants (Terminalia bellerica, Terminalia chebula and Terminalia horrida): Characterization, quantitation and determination of antioxidant capacities

Thirty-four polyphenolic substances in methanol extracts of the fruits of Terminalia bellerica, Terminalia chebula and Terminalia horrida, three plants used in Egyptian folk medicine, were initially identified by HPLC-ESI-MS and quantitated by analytical HPLC after column chromatography on Sephadex LH-20. After purification by semi-preparative HPLC the compounds were identified by their mass and fragmentation patterns using ESI-MS-MS. For several compounds detailed ¹H/¹³C NMR analysis at 600 MHz was performed. Two polyphenolics, namely 4-O-(4″-O-galloyl-α-l-rhamnopyranosyl)ellagic acid and 4-O-(3″,4″-di-O-galloyl-α-l-rhamnopyranosyl)ellagic acid were identified by NMR. Antioxidant capacities of the raw fruit extracts and the major isolated substances were determined using the 1,1-diphenyl-2-picrylhydrazyl radical (DPPH), oxygen radical absorbance capacity (ORAC) and ferric reducing ability of plasma (FRAP) in vitro assays and indicated that chebulic ellagitannins have high activity which may correlate with high potential as cancer chemopreventive agents. Therefore, further studies (metabolism, bioavailability and toxicity) of the polyphenolics in Terminalia species using preclinical models and in vivo human intervention trials are warranted.     

Pendulaosides A and B. Two acylated triterpenoid saponins from Harpullia pendula seed extract

Two new acylated triterpenoid saponins named pendulaosides A and B as well as the known phenolic compounds methyl gallate, gallic acid, 1,2,3,6-tera-O-galloyl-β-d-glucose and 1,2,3,4,6-penta-O-galloyl-β-d-glucose, were isolated from the seeds of Harpullia pendula. The structures of pendulaosides A and B were determined using extensive 1D and 2D NMR analysis and mass spectrometry as well as acid hydrolysis, as 3-O-β-d-glucopyranosyl-(1→2)-[α-L-arabinofuranosyl-(1→3)]-β-d-glucuronopyranosyl-22-O-angeloyl-3β,16α,22α,24β,28-pentahydroxylolean-12-ene and 3-O-β-d-glucopyranosyl-(1→2)-[α-L-arabinofuranosyl-(1→3)]-β-d-glucuronopyranosyl-16-O-(2-methylbutyroyl)-3β,16α,22α,24β,28-pentahydroxylolean-12-ene, respectively. To the best of our knowledge the two triterpene parts 22-O-angeloyl-3β,16α,22α,24β,28-pentahydroxylolean-12-ene and16-O-(2-methylbutyroyl)-3β,16α,22α,24β,28-pentahydroxylolean-12-ene have never been characterized before. The two isolated saponins were assayed for their in-vitro cytotoxic activity against the three human tumor cell lines HepG2, MCF7 and PC3. The results showed that pendulaoside A exhibited moderate activity on PC3 cell line with IC50value equal to 13.0 μM and weak activity on HepG2 cell line with IC50 value equal to 41.0 μM. Pendulaoside B proved to be inactive against the three used cell lines.     

The flavonoids of ferns in the isolated genera Loxsoma and Loxsomopsis

Kaempferol and quercetin 3-O-glucosides and 3-O-rhamnoglucosides are common to both Loxsoma cunninghamii and Loxsomopsis costaricensis, but in the former the new flavonoid glycosides, kaempferol and quercetin 3-O-glucoside-7-O-arabinoside have also been identified. The data are consistent with the proposed taxonomic relationship between these geographically isolated genera. Comparative flavonoid chemistry indicates that the Loxsomaceae may be a primitive family, not closely related to the Hymenophyllaceae or the Cyatheaceae.     

Substrate-like water soluble lipase inhibitors from Filipendula kamtschatica

Filipendula kamtschatica is a plant utilized as a traditional medicine by Ainu people in Japan, but its chemical constituents are not much studied. Pancreatic lipase inhibitors are a promising tool for the treatment of obesity. We searched for natural lipase inhibitors from F. kamtschatica and two new compounds were isolated along with the known flavonoid glycoside. The structure elucidation of new compounds revealed these two to be 2-O-caffeoyl-4-O-galloyl-l-threonic acid and 3-O-caffeoyl-4-O-galloyl-l-threonic acid, which can be recognized as a pancreatic lipase’s substrate-like structure. The isolated compounds all showed an inhibitory activity against porcine pancreatic lipase and one of the isomer, 3-O-caffeoyl-4-O-galloyl-l-threonic acid, possessed the most potent activity with IC₅₀ value showing an order lower value compared to others. The substrate-like structure of the new compounds seemed to be important for their activity.     

Synthesis and some reactions of methyl 4,6-O-benzylidene-2,3-dideoxy-2-phenylazo-β-d-erythro-hex-2-enopyranoside

Methyl 4,6-O-benzylidene-2,3-dideoxy-2-phenylazo-β-d-erythro-hex-2-enopyranoside has been synthesised, and its addition reactions with methoxide, azide, hydride, and deuteride ions have been studied. Comment is made on the stereochemistry of addition reactions of 2- and 3-phenylazo derivatives of methyl 4,6-O-benzylidene-2,3-dideoxy-d-hex-2-enopyranosides.     

Control by bacteriophage T4 of two sequential phosphorylations of the alpha subunit of Escherichia coli RNA polymerase

The effect of 2′-O-methylation upon the base-stacking properties of dinucleoside monophosphates has been studied by circular dichroism measurements over the temperature range from ?20 °C to +80 °C at high and at low salt concentration of 13 2′-O-methyl derivatives in neutral aqueous solution. It is found that 2′-O methylation generally enhances the stacking propensity of dinucleoside monophosphates except for the dimers with adenine in the 3′-linked nucleoside, where the converse trend is observed. The influence of 2′-O-methylation upon the base-stacking property of a dimer correlates in part with the effect of a reduction in salt concentration, suggesting that the 2′-O-methyl group effects the stacking by displacing ions from the immediate environment of the dimer as well as by intramolecular steric effects. The dimers which exhibit an enhanced stacking due to the 2′-O-methylation are found in a larger than statistical abundance in yeast transfer RNA, whereas those showing a reduced stacking occur in minor abundance. These observations are discussed in relation to some current views on the role of modified nucleosides in the conformation of ribonucleic acids.     

Antinociceptive activity of the HPLC- and MS-standardized hydroethanolic extract of Pterodon emarginatus Vogel leaves

Several studies have demonstrated the analgesic and anti-inflammatory effects of fruit and seed extracts from Pterodon emarginatus Vogel (Fabaceae). The objective of this study was to evaluate the antinociceptive activity of the hydroethanolic extract of P. emarginatus leaves in mice and characterize its chemical composition using HPLC coupled to UV–vis diode array detection and mass spectrometry with electrospray ionization. Our results showed that the doses of 500 and 1000 mg/kg produced an antinociceptive effect, as observed in the hot plate test and writhing induced by acetic acid. The chromatographic profile and spectral mass data suggest the presence of di-C-glycosylflavones (e.g., vicenin-2 and schaftoside), C,O-glycosylflavones (e.g., chrysoeriol-8-C-glucosyl-2″-O-glucuronide-6-C-arabinoside) and luteolin-7-O-rutinoside as the main constituents. Lower levels of oleanane-type saponins, such as soyasaponin Bb and Be, and the saponin derivatives hederagenin and aglycone B, which are typical of Fabaceae family, were also found. From this study, it is suggested that the analgesic effect observed is not due to the terpenoids previously reported from fruit and seed extracts, but could be attributed to flavones and the hederagenin derivatives that were identified as main constituents of the hydroethanolic extract from the leaves.