Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “GLYCOSIDES”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,495 records · Page 83Linked to original sources
PubMed1991

Structure of the glycopeptidolipid antigen of serovar 20 of the Mycobacterium avium serocomplex, synthesis of allyl glycosides of the outer di- and tri-saccharide units of the antigens of serovars 14 and 20, and serology of the derived neoglycoproteins.

The tetrasaccharide hapten released from the glycopeptidolipid (GPL) antigen of Mycobacterium avium serovar 20 has been characterized as O-(2-O-methyl-alpha-D-rhamnopyranosyl)-(1----3)-O-(2-O-methyl-alpha-L- fucopyranosyl)-(1----3)-alpha-L-rhamnopyranosyl-(1----2)-6-deoxy-L-talos e. Syntheses are reported of allyl glycosides of the outer disaccharide unit of this hapten, O-(2-O-methyl-alpha-D-rhamnopyranosyl)-(1----3)-2-O-methyl-alpha-L-fu copyranose , and also of the outer di- and tri-saccharide units of the GPL antigen of M. avium serovar 14, O-(N-formyl-alpha-L-kansosaminyl)-(1----3)-2-O-methyl-alpha-D-rham nopyranose and O-(N-formyl-alpha-L-kansosaminyl)-(1----3)-O-(2-O-methyl-alpha-D- rhamnopyranosyl)-(1----3)-2-O-methyl-alpha-L-fucopyranose. The key steps in the latter synthesis involve the preparation of allyl 4-azido-4,6-dideoxy-3-C-methyl-2-O-methyl-alpha-L-mannopyranoside as a precursor for the N-formylkansosamine unit, followed sequentially by conversion into and use of a trichloroacetimidate as glycosyl donor for di- and tri-saccharide formation, O-deacylation, reduction, and N-formylation. The allyl glycosides, representative of the haptens from both serovars, have been converted into neoglycoproteins (NGPs) and their serological activities have been compared in the light of the structural relationship between them.

Antigens, Bacterial↗
PubMed1993

Formation of alpha-(1-->6), alpha-(1-->3), and alpha-(1-->2) glycosidic linkages by dextransucrase from Streptococcus sanguis in acceptor-dependent reactions.

Dextransucrase from Streptococcus sanguis 10558 was found to synthesize alpha-(1-->6), alpha-(1-->3), and alpha-(1-->2) linkages during an acceptor-dependent glucosyl transfer reaction. Normally, new glucosyl residues are added at C-6 of monosaccharide acceptors. However, sugars blocked at C-6 also can serve as good acceptors. The disaccharide and trisaccharide products formed when methyl 6-bromo-6-deoxy-alpha-D-glucopyranoside was used as acceptor were isolated and characterized. Both were found to contain only alpha-(1-->3) glycosidic bonds. This supports the hypothesis that when C-6 is blocked the acceptor binds to the enzyme in a flipped orientation, resulting in an approximate exchange in space of the C-3 and C-6, thereby putting C-3 adjacent to the active site. The second alpha-(1-->3) links in the trisaccharide are formed by a single-chain mechanism without release of the intermediate disaccharide. With maltose as acceptor, new glucosyl residues are added at C-6'. However, if that position is blocked with a bromine atom, the resulting compound, 6'-bromo-6'-deoxy-maltose, can still serve as an acceptor. The product in this case was isolated and characterized. The new glycosidic link was found to be alpha-(1-->2).

Carbohydrate Conformation↗
PubMed1993

Synthesis of the laminara-oligosaccharide methyl beta-glycosides of dp 3-8.

Ethyl 2,3,4,6-tetra-O-acetyl-1-thio-alpha-D-glucopyranoside has been prepared in a good yield by anomerization of the corresponding beta-thioglucoside with tin(IV) chloride and transformed, in three steps, into ethyl 2-O-benzoyl-4,6-O-benzylidene-1-thio-alpha-D-glucopyranoside (18). Chloroacetylation of 18, followed by treatment of the product with chlorine gave crystalline 2-O-benzoyl-4,6-O-benzylidene-3-O-chloroacetyl-beta-D-glucopyranosyl chloride (20). This was coupled with methanol in the presence of silver carbonate-silver perchlorate and the product was O-dechloroacetylated to afford methyl 2-O-benzoyl-4,6-O-benzylidene-beta-D-glucopyranoside (22). Silver triflate-promoted glucosylation of 18 with 20 gave a beta-(1-->3)-linked disaccharide derivative, reaction of which with chlorine yielded crystalline O-(2-O-benzoyl-4,6-O-benzylidene-3-O-chloroacetyl-beta-D-glucopyranosyl) - (1-->3)-2-O-benzoyl-4,6-O-benzylidene-beta-D-glucopyranosyl chloride (24). Likewise, condensation of 22 with 20 gave a beta-(1-->3)-linked disaccharide glycoside, which was partially deprotected to give methyl O-(2-O-benzoyl-4,6-O-benzylidene-beta-D-glucopyranosyl)-(1-->3)-2-O-benz oyl- 4,6-O-benzylidene-beta-D-glucopyranoside (26). The methyl beta-glycosides of a homologous series of (1-->3)-linked beta-D-gluco-oligosaccharides from the tri- to the octa-saccharide have been synthesized in a blockwise manner by using 22 and 26 as the glycosyl acceptors, 24 as the disaccharide donor, and silver triflate as the promoter.

Carbohydrate Conformation↗
PubMed1993

Synthesis of the methyl glycosides of a tri- and a tetra-saccharide related to heparin and heparan sulphate.

The methyl glycoside of a tetrasaccharide isolated from heparin, methyl O-(alpha-L-idopyranosyluronic acid)-(1-->4)-O-(2-acetamido-2-deoxy-alpha-D- glucopyranosyl)-(1-->4)-O-(beta-D-glucopyranosyluronic acid)-(1-->3)-O-beta-D-galactopyranoside disodium salt and a trisaccharide derivative thereof, methyl O-(alpha-L-idopyranosyluronic acid)-(1-->4)-O-(2-acetamido-2- deoxy-alpha-D-glucopyranosyl)-(1-->4)-O-beta-D-glucopyranosyluronic acid disodium salt, were synthesized using a block-type strategy. A suitable protected disaccharide block of iduronic acid and glucosamine (IdoA-GlcN) was used as a key intermediate for the syntheses and was glycosidated with a protected galactose derivative and a disaccharide block of glucuronic acid and galactose (GlcA-Gal) to give tri- and tetra-saccharide derivatives, respectively. Deprotection gave the target compounds.

Carbohydrate Sequence↗
PubMed1996

Molecular cloning and bacterial expression of a cDNA encoding furostanol glycoside 26-O-beta-glucosidase of Costus speciosus.

Furostanol glycoside 26-O-beta-glucosidase (F26G) purified from Costus speciosus rhizomes was digested with endoproteinase, and several internal peptide fragments were obtained. Degenerate oligonucleotide primers based on amino acid sequences of the peptides were used for amplification of F26G cDNA fragments by applying nested polymerase chain reactions to cDNAs from in vitro cultured plantlets of C. speciosus. Using primers based on sequences of the cDNA fragments, the 5'- and 3'-end clones were isolated by rapid amplification of cDNA ends (RACE) methods. Finally, the entire coding portion of F26G cDNA was cloned by using primers designed from sequences of the RACE products. The deduced amino acid sequence of CSF26G1, the protein encoded by the cloned cDNA, consists of 562 amino acids and shows high homology to a widely distributed family of beta-glucosidases (BGA family). Cell-free homogenate of Escherichia coli expressing CSF26G1 cDNA showed beta-glucosidase activity specific for cleavage of the C-26 glucosidic bond of furostanol glycosides.

Amino Acid Sequence↗
PubMed1990

Analysis of N- and O-glycosidically bound sialooligosaccharides in glycoproteins by high-performance liquid chromatography with pulsed amperometric detection.

N-Glycosidically bound sialooligosaccharides in a model glycoprotein of serum type (porcine thyroglobulin) were released by pronase digestion, followed by hydrazinolysis. The resulting oligosaccharides were re-N-acetylated and reduced with sodium borohydride. On the other hand, O-glycosidically bound sialooligosaccharides were released from a mucin-type glycoprotein (bovine submaxillary mucin) with alkali in the presence of sodium borohydride. The reduced oligosaccharides thus obtained from both types of glycoproteins were analysed by high-performance liquid chromatography on a column of a latex-type pellicular anion-exchange resin with strong alkali as eluent. These sequential procedures were useful for mapping of oligosaccharides in glycoproteins.

Amino Acids↗
PubMed1993

Column liquid chromatographic determination of flavanone glycosides in Citrus. Application to grapefruit and sour orange juice adulterations.

Six flavone glycosides were separated by HPLC using RP-18 with a quaternary mobile phase mixture [water-acetonitrile-tetrahydrofuran-acetic acid (80:16:3:1, v/v)]. This procedure was applied to the separation and determination of the most important flavanone glycosides contained in pure grapefruit and sour orange juices and mixtures. This method can be used for quality control of industrial concentrates and juices.

Beverages↗
PubMed1990

Two flavonol glycosides from the underground parts of Vancouveria hexandra.

Two new flavonol glycosides were isolated from the roots and rhizomes of Vancouveria hexandra. The glycosides were determined by chemical and spectral means to be anhydroicaritin 3-galactosyl(1----3) rhamnoside-7-glucoside and anhydroicaritin 3-[6-O-acetyl-galactosyl(1----3)rhamnoside]-7-glucoside.

Flavonoids↗
PubMed1992

Two flavonol glycosides from Vancouveria hexandra.

In addition to two known glycosides, ikarisoside F and epimedin A, two new glycosides of a flavonol with a gamma, gamma-dimethylallyl group were isolated from the underground and the aerial parts of Vancouveria hexandra. The structures were determined to be des-O-methylanhydroicaritin 3,7-diglucoside and anhydroicaritin 3-glucosyl (1----3)rhamnoside-7-glucoside by means of spectral analysis.

Carbohydrate Sequence↗
PubMed1991

Two flavonol glycosides, hexandrasides C and D, from the underground parts of Vancouveria hexandra.

In addition to four known glycosides, icariin, epimedin B, epimedosides A and E, two new glycosides of a flavonol with a gamma,gamma-dimethylallyl group were isolated from the underground parts of Vancouveria hexandra. The structures were determined to be des-O-methyl-anhydroicaritin 3-O-beta-D-xylopyranosyl(1----2)-alpha-L-rhamnopyranoside 7-O-beta-D-glucopyranosyl(1----2)-beta-D-glucopyranoside and anhydroicaritin 3-O-alpha-L-rhamnopyranosyl(1----3)-alpha-L-rhamnopyranoside 7-O-beta-D-glucopyranoside by means of spectral analysis.

Carbohydrate Sequence↗
PubMed1992

Balanitoside, a furostanol glycoside, and 6-methyldiosgenin from Balanites aegyptiaca.

In addition to a known spirostanol glycoside, balanitin-3, and a new sapogenol, 6-methyldiosgenin, a new furostanol saponin, balanitoside has been isolated from the fruits (mesocarp) of Balanites aegyptiaca. The structure of the glycoside has been determined as 26-O-beta-D-glucopyranosyl-3 beta, 22,26-trihydroxy-furost-5-ene 3-O-alpha-L-rhamnopyranosyl-(1-->2)-beta-D- glucopyranosyl-(1-->4)-beta-D-glucopyranoside, on the basis of spectroscopic and chemical evidence.

Carbohydrate Sequence↗
PubMed1995

Cycloartane triterpene glycosides from Astragalus trigonus.

Three new cycloartane glycosides, trigonoside I, II and III, and the known astragalosides I and II were isolated from the roots of Astragalus trigonus. The structures of the new glycosides were totally elucidated by high field (600 MHz) NMR analyses as cycloastragenol-6-O-beta-xylopyranoside, cycloastragenol-3-O-[alpha-L-arabinopyranosyl(1-->2)-beta-D- xylopyranosyl]- 6-O-beta-D-xylopyranoside and cycloastragenol-3-O-[alpha-L-arabinopyranosyl (1-->2)-beta-D-(3-O-acetyl)-xylopyranosyl]-6-O-beta-D-xylopyranoside.

Carbohydrate Conformation↗
PubMed1996

Iridoid glycosides from Thunbergia grandiflora.

The novel iridoid glycosides, isounedoside and grandifloric acid, were isolated from Thunbergia grandiflora. Grandifloric acid contains C-10 as a carboxylic acid group, the presence of which was predicted by recent iridoid biosynthesis studies carried out within T. alata. Isounedoside contains a rare 6,7-epoxide functional group. A revision in some of the NMR spectral assignments for the known iridoid glycoside alatoside was also made.

Diterpenes↗
PubMed1996

Phenylethanoid glycosides from Stachys officinalis.

From the aerial parts of Stachys officinalis, six new phenylethanoid glycosides, named betonyosides A-F, and six known phenylethanoid glycosides, acetoside, acetoside isomer, campneosides II, forsythoside B and leucosceptoside B, were isolated and their structures were elucidated from spectroscopic and chemical evidence. Campneosides II were separated into two epimers.

Carbohydrate Conformation↗
PubMed1979

Mutagenicity of anthraquinone and benzanthrone derivatives in the Salmonella/microsome test: activation of anthraquinone glycosides by enzymic extracts of rat cecal bacteria.

Approximately 70 anthraquinones and 20 benzanthrones were assayed for mutagenicity in the Salmonella/microsome test, employing 5 tester strains and Aroclor 1254 induced rat-liver microsomes. About one-third of the anthraquinones were frameshift mutagens, particularly phenolic and nitro anthraquinones. The most potent mutagens detected were of plant origin. Lucidin (1,3-dihydroxy-2-hydroxymethylanthraquinone) and its 2-ethyl ether gave values of 70 and 82 revertants per nmol, respectively, with strain TA100 (and microsomes in the case of the ether). A number of glycosides of mutagenic hydroxyanthraquinones were found to be nonmutagenic in the standard assay procedure, but could be activated by incorporation of cell-free sonic extracts of rat cecal bacteria, e.g., alizarin-2-O-beta-D-glycoside, emodin-1 (8)-monoglucoside and lucidin-3-O-primveroside. Over one-third of the benzanthrones tested were frameshift mutagens for Salmonella; the most potent response of 64 revertants/nmol was obtained with 3-p-toluidinobenzanthrone and microsomal activation in strain TA98.

Anthraquinones↗
PubMed1988

Preparation and evaluation of technetium-99m labeled cardiac glycoside derivatives as potential myocardial imaging agent.

Three cardiac glycosides, two natural, cymarin and convallotoxin and one synthetic, strophanthidin-beta-D-glucoside were converted to their thiosemicarbazone and subsequently radiolabeled with 99mTc by chelation. The resulting radioactive chelate complexes were evaluated in animals to determine the suitability of this class of compounds for myocardial imaging. It was observed from the animal biodistribution data of the three radioactive compounds, there was a considerable variation in the heart to non-target organ uptake ratio. A possible explanation of this variation was offered in the light of their lipophilic character, protein binding ability and affinity towards non-target receptors. It is anticipated that this study may help to develop a 99mTc-cardiac glycoside complex with better distribution characteristics, and such a compound may offer a suitable alternative to 201Tl, which is at present used for myocardial imaging.

Animals↗
PubMed2004

Biotransformation of soy isoflavone-glycosides in laying hens: intestinal absorption and preferential accumulation into egg yolk of equol, a more estrogenic metabolite of daidzein.

Dietary soy-isoflavones have recently been noted as phytoestrogens with potentially beneficial effects on human health, and they are biologically transformed in the intestinal tract into aglycones and further into several specific metabolites. Here we report that in laying hens daidzin, a soy isoflavone-glycoside, in the diet was transformed into equol, absorbed, transported in circulating peripheral blood, and preferentially accumulated into egg yolk in its conjugated form. Laying hens were fed experimental diets containing two levels of soy isoflavone-glycosides (177 or 528 mg per 100 g diet) for 21 or 42 days, and blood and eggs were collected at 1- to 9-day intervals. HPLC analyses revealed that most of the isoflavones (daidzein, glycitein, and genistein) and a metabolite, equol, were present in blood and egg yolk in conjugated form. The concentration of equol-conjugates in blood plasma and egg yolk was higher than any of the other three isoflavone-conjugates analyzed and, especially in egg yolk, the equol-conjugates comprised no less than 60% of the total isoflavone-conjugates. The isoflavones, including equol, distributed mostly (95%) in the high-density fraction of blood serum, and more (65%) in the granule fraction of egg yolk. These results raise the possibility that feeding domestic animals soy-based fodder produces animal-based foods rich in a more active form of phytoestrogens.

Animal Feed↗