3-O-Methyl galactose found in polysaccharides of Lampteromyces japonicus.

A polysaccharide fraction from Lampteromyces japonicus contained a sugar (4%), which was identified as 3-O-methyl galactose by demethylation with boron trichloride, periodate oxidation of the methyl glycoside derivative and gas chromatography-mass spectrometry of the alditol acetate derivative.

Conformational changes in concanavalin A associated with demetallization and alpha-methylmannose binding studied by Fourier transform infrared spectroscopy.

Infrared spectra of concanavalin A have been obtained both in the absence and in the presence of the metal ions, Mn2+ and Ca2+, and the saccharide, alpha-methylmannose. Second derivative calculations have been used to determine the frequencies of the different amide I and II components. In the demetallized protein dissolved in H2O buffer, absorptions in the amide I, II and III regions at 1695 and 1634, 1532 and 1237 cm-1, respectively, are assigned to beta-structure, while absorptions at 1563 and both 1318 and 1343 cm-1 are assigned to turns and bends. After deuterium exchange, the residual amide II maximum in the difference spectrum shifts from 1538 to 1563 cm-1, indicating that exchange is faster in the beta-structure than in the turns. In the presence of Mn2+ and Ca2+, the amide II band component at 1532 cm-1 shifts 4-6 cm-1 to higher wavenumbers, and the amide I band component at 1634 shifts 1 cm-1 in the same direction, both in H2O and 2H2O buffers, suggesting changes in the hydrogen-bonding network of a large portion of the protein, particularly in the beta-sheet regions. The addition of alpha-methylmannose increases the magnitude of exchange from 55% to above 90%. Comparison with existing X-ray crystallographic data has been made, and the usefulness of FT-IR to complement this technique is discussed.

Mining chemodiversity from biodiversity: pharmacophylogeny of medicinal plants of Ranunculaceae.

This paper reports a pharmacophylogenetic study of a medicinal plant family, Ranunculaceae, investigating the correlations between their phylogeny, chemical constituents, and pharmaceutical properties. Phytochemical, ethnopharmacological, and pharmacological data were integrated in the context of the systematics and molecular phylogeny of the Ranunculaceae. The chemical components of this family included several representative metabolic groups: benzylisoquinoline alkaloids, ranunculin, triterpenoid saponin, and diterpene alkaloids, among others. Ranunculin and magnoflorine were found to coexist in some genera. The pharmacophylogenetic analysis, integrated with therapeutic information, agreed with the taxonomy proposed previously, in which the family Ranunculaceae was divided into five sub-families: Ranunculoideae, Thalictroideae, Coptidoideae, Hydrastidoideae, and Glaucidioideae. It was plausible to organize the sub-family Ranunculoideae into ten tribes. The chemical constituents and therapeutic efficacy of each taxonomic group were reviewed, revealing the underlying connections between phylogeny, chemical diversity, and clinical use, which should facilitate the conservation and sustainable utilization of the pharmaceutical resources derived from the Ranunculaceae.

[Structure and immunochemical properties of the urinary oligosaccharides excreted during induced galactosuria]. / Structure et propriétés immunochimiques des oligosaccharides urinaires excrétés au cours de la galactosurie provoquée

Induced galactosuria is characterized by the excretion in urine of large amounts of new oligosaccharides, the structure of which are in connection with blood-group phenotypes ABH, Lewis and Secretor: O group : O-alpha-L fucopyranosyl-(1 leads to 2)-D galactopyranose et O-alpha-L fucopyranosyl-(1 leads to 2)-O-beta-D galactopyranosyl-(1 leads to 3)-[O-alpha-L fucopyranosyl-(1 leads to 4)]-O-beta-D 2-deoxy-2 acetamido-glucopyranosyl-(1 leads to 4)-[O-alpha-L fucopyranosyl-(1 leads to 6)]-D-galactopyranose. A group: O-alpha-D-2-deoxy-2 acetamido-galactopyranosyl-(1 leads to 3)-[O-alpha-L fucopyranosyl-(1 leads to 2)]-D galactopyranose et O-alpha-D-2-deoxy-2 acetamido-galactopyranosyl-(1 leads to 3)-[O-alpha-L fucopyranosyl-(1 leads to 2)]-O-beta-D galactopyranosyl-(1 leads to 3)-[O-alpha-L fucopyranosyl-(1 leads to 4)]-O-beta-D-2-deoxy-2 acetamido-glucopyranosyl-(1 leads to)-[O-alpha-L fucopyranosyl-(1 leads to 6)]-D galactopyranose. B group : O-alpha-D galactopyranosyl-(1 leads to 3)-[O-alpha-L fucopyranosyl-(1 leads to 2)]-D galactopyranose et O-alpha-D galactopyranosyl-(1 leads to 3)-[O-alpha-L fucopyranosyl-(1 leads to 2)]-O-beta-D galactopyranosyl-(1 leads to 3)-[O-alpha-L fucopyranosyl-(1 leads to 4)]-O-beta-D-2-deoxy-2 acetamido-glucopyranosyl-(1 leads to 4)-[O-alpha-L fucopyranosyl-(1 leads to 6)]-D-galactopyranose.

A novel sphingophosphonoglycolipid containing 3-O-methylgalactose isolated from the skin of the marine gastropod Aplysia kurodai.

A novel sphingophosphonolipid was isolated from the skin of a marine gastropod, Aplysia kurodai. It was composed of one mol each of sphingosine base, fatty acid, glucose, galactosamine, and an unknown sugar and two mol each of galactose and aminophosphonic acid. The unknown sugar was identified as 3-O-methylgalactose by GC-mass spectrometry of the alditol acetate derivative and by GLC of the trimethylsilyl methylglycoside derivative. The aminophosphonic acid was identified as 2-aminoethylphosphonic acid by TLC of the free acid and the dinitrophenyl (DNP-) compound and by GLC of the O-di-trimethylsilyl-N-isothiocyanate compound. Thus, a ceramide bis(2-aminoethylphosphono)-pentaoside structure having an oligosaccharide chain consisting of one mol each of glucose, 3-O-methylgalactose and galactosamine and two mol of galactose was proposed.

Oligosaccharide microanalysis by c.d. spectroscopy. Reference curves for D-mannose derivatives.

This study completes the spectroscopic basis for a novel oligosaccharide microanalytical method, wherein a derivatization sequence provides monosaccharide subunits bearing two types of exciton-coupling chromophore groups ("bichromophoric") for circular dichroic spectroscopy, namely 4-bromobenzoate (lambda max 245 nm) and 4-methoxycinnamate (lambda max 311 nm). The 24 possible derivatives of methyl alpha-D-mannopyranoside bearing two chromophore and two acetate groups have been prepared and their c.d. spectra recorded. These spectra have been used to calculate the c.d. curves of the 14 possible tetrachromophic derivatives according to the pairwise additivity rule. The accuracy of these calculations has been demonstrated for six representative derivatives. The c.d. curves obtained here, together with curves of the corresponding D-glucose and D-galactose derivatives, comprise a set of 42 unique and distinctive spectra which can be utilized to identify sugars and their linkage patterns, and thus represent the basis for an alternative to methylation analysis which does not rely upon synthetic standards.

Determination of position of substitution on 2-acetamido-2-deoxy-D-galactosyl residues in glycolipids.

The substitution site on 2-acetamido-2-deoxy-D-galactosyl residues in oligosaccharide chains of glycolipids was determined by permethylation of the glycolipid with methyl iodide in the presence of dimethylsulfinyl carbanion, methanolysis of the permethylated product under mild conditions, acetylation with acetic anhydride-pyridine, and identification of the resulting substituted methyl glycosides of 2-deoxy-2(N-methylacetamido)-D-galactose by g.l.c. The method was applied to glycolipids of known structure, including normal brain ganglioside, Tay-Sachs ganglioside, and Forssman glycolipid.

[Determination of ranunculin in Pulsatilla chinensis and synthetic ranunculin by reversed phase HPLC].

A method for the determination of ranunculin in Pulsatilla chinensis and synthetic ranunculin by reversed phase HPLC using betamethasone as internal standard is described. The column employed was a 10 micron LiChrosorb RP-18 (230 x 14 mm), the eluting solvent consisted of methanol-water (40:10, V/V) and the effluent was monitored at 225 nm. The advantages of this method are simple, rapid and accurate. The coefficients of variation are less than 1%.

[Analysis of polysaccharides used as food additives. VI. Identification of mixtures of polysaccharides by methylation analysis (author's transl)]. / Beiträge zur Analytik von als Lebensmittelzusatzstoffe verwendeten Polysacchariden. VI. Identifizierung von Polysaccharidgemischen mit Hilfe der Methylierungsanalyse.

Polysaccharide mixtures used as stabilizers having identical sugar units, but differing in their linkages can be identified with confidence by means of methylation analysis. Such mixtures are methylated with sodium hydride and methyl iodide in anhydrous dimethylsulfoxide. The methylated products are acid hydrolyzed and the resulting methyl sugars are separated and identified by thinlayer- or gaschromatography.

A compound representing the D-glycerate terminus of the methylglucose-containing polysaccharide of Mycobacterium smegmatis.

In order to study the structure of the methylglucose-containing polysaccharide (MGP) of Mycobacterium smegmatis by NMR spectroscopy, we have prepared the model compound O-alpha-D-glucopyranosyl-(1 leads to 2)-D-glyceric acid. This compound, which represents the aglycon-containing terminus of MGP, was made from leucorse [O-alpha-D-glucopyranosyl-(1 leads to 5)-D-fructopyranose] by successive treatment with sodium borohydride, lead tetraacetate, and hypobromite. The structure of O-alpha-D-glucopyranosy.-(1 leads to 2)-D-glyceric acid was confirmed by chemical and enzymic methods. 13C and 1H NMR spectra of this compound, together with spectra of several disaccharides, were obtained for future reference in the polysaccharide study. The nine resonances in the 13C spectrum were assigned by comparison with the spectrum of methyl alpha-D-glucopyranoside. Analysis of the 1H NMR spectrum showed that the two methylene protons on C-3 of the glycerate moiety were less equivalent in the sodium salt than in the acid. This may be attributable to hydrogen bonding between the carboxylate and the hydrogen atom of the glycerate 3-hydroxyl group.

Occurrence of 3-O-methylmannose in the polysaccharide of Leptospira biflexa Urawa.

3-O-methylmannose was identified by gas-liquid chromatography-mass spectrometry in the acid hydrolysate of the polysaccharide of Leptospira biflexa Urawa.

Determination of carboxymethyl-D-glucoses in the product of hydrolytic depolymerization of carboxymethylcellulose by isotachophoresis.

Optimal conditions for isotachophoretic separation of carboxymethyl-D-glucoses formed by acidic depolymerization of carboxymethylcellulose were found. 6-O-carboxymethyl-D-glucose, 2-O-carboxymethyl-D-glucose and 3-O-carboxymethyl-D-glucose were identified and determined in the reaction mixture after carboxymethylcellulose hydrolysis. Relative reactivity of hydroxy groups in the glucopyranose unit of cellulose decreased in the following order: O(6)H greater than O(2)H much greater than O(3)H. This was found to be in agreement with the data published by other authors.