Flavonoid oligosides from georgian <Emphasis Type="Italic">Astragalus falcatus</Emphasis>

New flavonoid oligosides were isolated from leaves and flowers of Astragalus falcatus Lam. It was found on the basis of chemical transformations, UV, IR, PMR, ¹³ C NMR, HMBC, HSQC, 1D-TOCSY, and mass spectral properties that falcoside C had the structure quercetin 3-O-[β-D-glucopyranosyl(1 → 3)-α-Lrhamnopyranosyl(1 → 6)]-β-D-galactopyranoside 7-O-β-D-glucopyranoside; falcoside D, isorhamnetin 3-O-[β-D-xylopyranosyl(1 → 3)-α-L-rhamnopyranosyl(1 → 6)]-β-D-galactopyranoside 7-O-α-Lrhamnopyranoside.     

Glucofructans from <Emphasis Type="Italic">Saussurea lappa</Emphasis> roots

Glucofructans from Saussurea lappa (Asteraceae) roots were studied. It was found that free fructose and oligomeric glucofructans (saccharose, 1-kestose, nystose, 1^F-β-fructofuranosylnystose, and 1^F-β-fructofuranosyl-1^F-β-fructofuranosylnystose) were present. The dominant polymer Sl-GF (MW 51.4 kDa), which was a linear inulin-type glucofructan consisting of β-(2 → 1)-bonded fructofuranose units, was isolated and characterized. The total content of glucofructans in Saussurea lappa roots was 476.97–578.27 mg/g.     

Steroidal glycosides from Allium cyrillii bulbs

Two spirostanol saponins, one of which was a new compound, were isolated among the steroidal glycosides of Allium cyrillii Ten. Bulbs. The structures of these glycosides were established using chemical and spectral analytical methods as β-D-glycopyranosyl-(1 → 2)-[β-D-xylopyranosyl-(1 → 3)]-β-D-glucopyranosyl-(1 → 4)β-D-galactopyranosyl-(1 → 3)-(25R)-5α-spirostan-2α,3β-diol and β-D-glucopyranosyl-(1 → 2)-[4-O-(3hydroxy-3-methylglutaryl)-β-D-xylopyranosyl-(1 → 3)]-β-D-glucopyranosyl-(1 → 4)-β-D-galactopyranosyl(1 → 3)-(25R)-5α-spirostan-2α,3β-diol.     

Triterpene glycosides from <Emphasis Type="Italic">Astragalus</Emphasis> and their genins. XC. Askendoside K from <Emphasis Type="Italic">Astragalus taschkendicus</Emphasis>

A new triterpene cycloartane glycoside called askendoside K was isolated from roots of Astragalus taschkendicus Bunge (Leguminosae). The structure of this glycoside was established using chemical and biochemical transformations and spectral data. Askendoside K was a bisdesmoside of cycloorbigenin C and had the structure 23R,24R-cycloartan-3β,6α,16β,23,24,25-hexaol 3-O-[(α-L-arabinopyranosyl)(1 → 2)-β-D-xylopyranoside],23-O-[(β-D-glucuronopyranosyl)(1 → 2)-β-D-glucopyranoside].     

A new furostanol glycoside with fatty acid synthase inhibitory activity from <Emphasis Type="Italic">Ophiopogon japonicusa</Emphasis>

A new furostanol glycoside, named ophiopogonin J (1), was isolated from the fibrous root of Ophiopogon japonicas. The structure of the compound was established as (25R)-26-[(O-β-D-glucopyranosyl-(1 → 2)-β-D-glucopyranosyl)]-20α -hydroxyfurost-5, 22-diene-3-O-α-L-rhamnopyranosyl-(1 → 2)-[β-D-xylopyranosyl(1 → 4)]-β-D-glucopyranoside on the basis of spectroscopic methods, including HR-ESI-MS and 1D and 2D NMR experiments.     

Structure of carbohydrate antigens from <Emphasis Type="Italic">Microbulbifer</Emphasis> sp. KMM 6242

A capsular polysaccharide (CPS) containing D-galactosamine uronic acid and D-alanine was isolated from a culture of the marine proteobacterium Microbulbifer sp. KMM 6242. 2D NMR spectroscopy showed that the CPS is a homopolymer of 2-acetamido-2-deoxy-N-(D-galacturonyl)-D-alanine with the structure →4)-β-D-GalpNAcA6(D-Ala)-(1→. An O-specific polysaccharide containing D-ribose and D-galactose was isolated from the cell-membrane lipopolysaccharide. 1D and 2D NMR spectroscopy established the structure of the disaccharide repeating unit of the polysaccharide as →3)-β-D-Ribf-(1→4)-β-D-Galp-(1→.     

Steroidal glycosides of gitogenin from Allium rotundum

Two new steroidal glycosides were isolated by fractionation of total extracted substances from inflorescences and flower stalks of Allium rotundum (Alliaceae). The structures were determined on the basis of chemical transformations, physical constants, and spectral data as 26-O-β-D-glucopyranosyl-(25R)-5α-furostan2α,3β,22α,26-tetraol 3-O-β-D-glucopyranosyl-(1 → 2)[β-D-xylopyranosyl-(1 → 3)]-β-D-glucopyranosyl(1 → 4)-β-D-galactopyranoside (2) and (25R)-5α-spirostan-2α,3β-diol 3-O-β-D-glucopyranosyl-(1 → 3)-βD-glucopyranosyl-(1 → 2)-[β-D-xylopyranosyl-(1 → 3)]-β-D-glucopyranosyl-(1 → 4)-β-D-galactopyranoside (3).     

Determination of the primary structure and carboxyl p<Emphasis Type="Italic">K</Emphasis><Subscript>A</Subscript>s of heparin-derived oligosaccharides by band-selective homonuclear-decoupled two-dimensional <Superscript>1</Superscript>H NMR

Determination of the structure of heparin-derived oligosaccharides by ¹H NMR is challenging because resonances for all but the anomeric protons cover less than 2 ppm. By taking advantage of increased dispersion of resonances for the anomeric H¹ protons at low pD and the superior resolution of band-selective, homonuclear-decoupled (BASHD) two-dimensional ¹H NMR, the primary structure of the heparin-derived octasaccharide ∆UA(2S)-[(1 → 4)-GlcNS(6S)-(1 → 4)-IdoA(2S)-]₃-(1 → 4)-GlcNS(6S) has been determined, where ∆UA(2S) is 2-O-sulfated ∆^4,5-unsaturated uronic acid, GlcNS(6S) is 6-O-sulfated, N-sulfated β-d-glucosamine and IdoA(2S) is 2-O-sulfated α-l-iduronic acid. The spectrum was assigned, and the sites of N- and O-sulfation and the conformation of each uronic acid residue were established, with chemical shift data obtained from BASHD-TOCSY spectra, while the sequence of the monosaccharide residues in the octasaccharide was determined from inter-residue NOEs in BASHD-NOESY spectra. Acid dissociation constants were determined for each carboxylic acid group of the octasaccharide, as well as for related tetra- and hexasaccharides, from chemical shift–pD titration curves. Chemical shift–pD titration curves were obtained for each carboxylic acid group from sub-spectra taken from BASHD-TOCSY spectra that were measured as a function of pD. The pK _As of the carboxylic acid groups of the ∆UA(2S) residues are less than those of the IdoA(2S) residues, and the pK _As of the carboxylic acid groups of the IdoA(2S) residues for a given oligosaccharide are similar in magnitude. Relative acidities of the carboxylic acid groups of each oligosaccharide were calculated from chemical shift data by a pH-independent method.     

Minor asterosaponin archasteroside C from the starfish <Emphasis Type="Italic">Archaster typicus</Emphasis>

A new minor asterosaponin (20S)-6-O-{β-d-fucopyranosyl-(1→2)-[β-d-fucopyranosyl-(1→4)-β-d-quinovopyranosyl-(1→2)]-β-d-quinovopyranosyl-(1→3)-β-d-quinovopyranosyl}-3β,6α,20-trihydroxycholest-9(11)-en-23-one 3-sulfate (archasteroside C) was isolated from the starfish Archaster typicus collected in shallow coastal waters of Vietnam. The structure of archasteroside C was determined by 2D NMR spectroscopy and electrospray ionization (ESI) tandem mass spectrometry.     

Characterization of a Thermostable Family 1 Glycosyl Hydrolase Enzyme from <Emphasis Type="Italic">Putranjiva roxburghii</Emphasis> Seeds

A 66-kDa thermostable family 1 Glycosyl Hydrolase (GH1) enzyme with β-glucosidase and β-galactosidase activities was purified to homogeneity from the seeds of Putranjiva roxburghii belonging to Euphorbiaceae family. N-terminal and partial internal amino acid sequences showed significant resemblance to plant GH1 enzymes. Kinetic studies showed that enzyme hydrolyzed p-nitrophenyl β-d-glucopyranoside (pNP-Glc) with higher efficiency (K _cat/K _m = 2.27 × 10⁴ M⁻¹ s⁻¹) as compared to p-nitrophenyl β-d-galactopyranoside (pNP-Gal; K _cat/K _m = 1.15 × 10⁴ M⁻¹ s⁻¹). The optimum pH for β-galactosidase activity was 4.8 and 4.4 in citrate phosphate and acetate buffers respectively, while for β-glucosidase it was 4.6 in both buffers. The activation energy was found to be 10.6 kcal/mol in the temperature range 30–65 °C. The enzyme showed maximum activity at 65 °C with half life of ~40 min and first-order rate constant of 0.0172 min⁻¹. Far-UV CD spectra of enzyme exhibited α, β pattern at room temperature at pH 8.0. This thermostable enzyme with dual specificity and higher catalytic efficiency can be utilized for different commercial applications.     

New triterpene glycoside from <Emphasis Type="Italic">Cyclamen adzharicum</Emphasis> tubers

Nine pure glycosides were isolated from total saponins of Cyclamen adzharicum Pobed. (Primulaceae). The total chemical structure of cyclamen F, 3β-O-[β-D-Xylp(1→2)]-[β-D-Glcp(1→2)]-(β-D-Glcp(1→4)-α-L-Arap)-16α-hydroxy-13,28-epoxy-30,30-dibutoxyolean, was elucidated using modern physicochemical and spectral methods (NMR, ¹H, ¹³C, HMBC, HMQC, DEPT, COSY, MS). A glycoside with the cyclamen F chemical structure has not been reported and, therefore, is a new organic compound.     

Identification of a new flavone glycoside from <Emphasis Type="Italic">Codonopsis nervosa</Emphasis>

A new flavone glycoside, luteolin 7-O-[(6″′-caffeoyl)-β-D-glucopyranosyl-(1 → 6)]-β-D-glucopyranoside (1), was isolated from Codonopsis nervosa, along with three other known compounds, luteolin 7-O-β-D-glucopyranoside (2), luteolin 7-O-gentiobioside (3), and tangshenoside VI (4). Their structures were determined on the basis of 1D and 2D NMR, IR, and HR-ESI-MS.     

A new flavonoid glycoside from <Emphasis Type="Italic">Galium verum</Emphasis>

A new flavonoid glycoside, an apigenin 7-O-(3,4-di-O-acetyl)-α-L-rhamnopyranosyl-(1 → _6)-β-D- glucopyranoside (1), was isolated from the 95% ethanol extract of Galium verum L. Its structure was elucidated by spectroscopic analysis.     

Structure of the repeat unit of the Alteromonas addita type strain KMM 3600T O-specific polysaccharide

The O-specific polysaccharide of Alteromonas addita type strain KMM 3600T is constructed of trisaccharide repeat units containing L-rhamnose, D-glucose, and D-galactose. It was established that the O-specific polysaccharide consists of trisaccharide repeat units with the structure →3)-α-D-Galp-(1→3)-α-L-Rhap-(1→3)-α-D-Glcp-(1→ based on monosaccharide analysis, Smith degradation, PMR and ¹³C NMR spectroscopy, and two-dimensional COSY, HSQC, and HMBC. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 445–447, September-October, 2008.     

A new triterpene glycoside from fruit of <Emphasis Type="Italic">Phytolacca americana</Emphasis>

Glycosides H and I, the structures of which were established by modern physicochemical analytical methods (PMR, ¹³C NMR, COSY, TOCSY, HMBC, MS) and acid-base hydrolysis, were isolated from the purified total saponins from fruit of Phytolacca americana containing at least 10 triterpene glycosides by rechromatography of enriched fractions over a column of silica gel. Glycoside H was a bidesmoside of phytolaccageninic acid, which was isolated earlier from cell culture of Phytolacca acinosa. Glycoside I was 3-O-(β-D-xylopyranosyl-(1 → 3)-β-D-galactopyranosyl-(1 → 3)- β -D-xylopyranosyl)-28-O- β -D-glucopyranosyl phytolaccagenin, which was isolated by us for the first time.     

Polysaccharide hydrolases from leaves of Boscia senegalensis: properties of endo-(1-->3)-beta-D-glucanase

The leaves of Boscia senegalensis are traditionally used in West Africa in cereal protection against pathogens, pharmacologic applications, and food processing. Activities of α-amylase, β-amylase, exo-(1→3, 1→4)-β-d-glucanase, and endo-(1→3)-β-d-glucanase were detected in these leaves. The endo-(1→3)-β-d-glucanase (EC3.2.1.39) was purified 203-fold with 57% yield. The purified enzyme is a nonglycosylated monomeric protein with a molecular mass of 36 kDa and pI≥10.3. Its optimal activity occurred at pH 4.5 and 50°C. Kinetic analysis gave V _max, k _cat , and K _m values of 659 U/mg, 395 s⁻¹, and 0.42 mg/mL, respectively, for laminarin as substrate. The use of matrix-assisted laser desorption ionization time-of-flight mass spectrometry and high-performance liquid chromatography revealed that the enzyme hydrolyzes not only soluble but also insoluble (1→3)-β-glucan chains in an endo fashion. This property is unusual for endo-acting (1→3)-β-d-glucanase from plants. The involvement of the enzyme in plant defense against pathogenic microorganisms such as fungi is discussed.     

A new flavone glycoside from the aerial part of <Emphasis Type="Italic">Scutellaria schachristanica</Emphasis>

The new flavone glycoside schachristanoside was isolated from the aerial part of Scutellaria schachristanica Zuz. (Lamiaceae). Spectral data and chemical transformations found that schachristanoside had the structure chrysin-7-O-[α-L-arabinopyranosyl-(1 → 6)]-β-D-glucopyranoside.     

Triterpene glycosides from <Emphasis Type="Italic">Astragalus</Emphasis> and their genins. LXXXIX. Askendoside H from <Emphasis Type="Italic">Astragalus taschkendicus</Emphasis>

A new triterpene glycoside of the cycloartane series that was called askendoside H was isolated from roots of Astragalus taschkendicus Bunge (Leguminosae). Its structure was elucidated based on chemical transformations and spectral data. Askendoside H was a bisdesmoside of cycloorbigenin C, 23R,24Rcycloartan-3β,6α,16β,23,24,25-hexaol 3-O-[(α-L-arabinopyranosyl)(1 → 2)-β-D-xylopyranoside] 23-O-βD-glucopyranoside.     

New class of carbohydrate-based nonionic surfactants: diblock co-oligomers of tri-<Emphasis Type="Italic">O</Emphasis>-methylated and unmodified cello-oligosaccharides

Mixtures of diblock co-oligomers of tri-O-methylated and unmodified cello-oligosaccharides have been found to be amphiphilic, as reported before. In order to clarify their accurate amphiphilic property, diblock co-oligomers of tri-O-methylated and unmodified cello-oligosaccharides with monodispersity, methyl β-d-glucopyranosyl-(1→4)-2,3,6–tri-O-methyl-β-d-glucopyranosyl-(1→4)-2,3,6–tri-O-methyl-β-d-glucopyranosyl-(1→4)-2,3,6-tri-O-methyl-β-d-glucopyranosyl-(1→4)-2,3,6-tri-O-methyl-d-glucopyranoside (1, pentamer), methyl β-d-glucopyranosyl-(1→4)- β-d-glucopyranosyl-(1→4)-2,3,6-tri-O-methyl-β-d-glucopyranosyl-(1→4)-2,3,6-tri-O-methyl-β-d-glucopyranosyl-(1→4)-2,3,6-tri-O-methyl-β-d-glucopyranosyl-(1→4)-2,3,6-tri-O-methyl-d-glucopyranoside (2, hexamer), and methyl β-d-glucopyranosyl-(1→4)-2,3,6-tri-O-methyl-β-d-glucopyranosyl-(1→4)- 2,3,6-tri-O-methyl-d-glucopyranoside (3, trimer) were synthesized independently. These compounds had higher surface activities compared to the mixture of diblock co-oligomers of tri-O-methylated and unmodified cello-oligosaccharides and commercially available methylcellulose (MC) SM-4. This paper describes the methods of synthesis of these compounds, and the influence of amphiphilic character on their surface activity. A new class of carbohydrate-based nonionic surfactant without long alkyl chain was discovered.     

Two new triterpenoid saponins from <Emphasis Type="Italic">Lysimachia davurica</Emphasis>

Two new saponins were isolated from an ethanol extract of the whole plants of Lysimachia davuria. The new saponins were respectively characterized as 3-O-{β-D-glucopyranosyl-(1→2)-[β-D-glucopyranosyl-(1→4)]-α-L-arabinopyranosyl}-3β,28-dihydroxyolean-12-en-30-oic acid-O-[β-D-xylopyranosyl-(1→2)-β-D-glucopyranosyl]-ester (1) and 3-O-{ β-D-glucopyranosyl-(1→2)-[β-D-glucopyranosyl-(1→4)]-α-L-arabinopyranosyl}-3β,28-dihydroxyolean-12-en-30-oic acid-O-β-D-glucopyranosyl-ester (2). Their structures were determined by 1D, 2D NMR and MS techniques. Published in Khimiya Prirodnykh Soedinenii, No. 5, pp. 466–468, September–October, 2007.