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At least 19 recordsLinked to original sources
PubMed2001

Glycosides in medicine: "The role of glycosidic residue in biological activity".

Numbers of biologically active compounds are glycosides. Sometimes, the glycosidic residue is crucial for their activity, in other cases glycosylation only improves pharmacokinetic parameters. Recent developments in molecular glycobiology brought better understanding to the aglycone vs. glycoside activities, and made possible to develop new, more active or more effective glycodrugs based on these findings - very illustrative recent example is the story of vancomycin. This paper deals with an array of glycosidic compounds currently used in medicine but also with biological activity of some glycosidic metabolites of the known drugs. It involves glycosides of vitamins, polyphenolic glycosides (flavonoids), alkaloid glycosides, glycosides in the group of antibiotics, glycopeptides, cardiac glycosides, steroid and terpenoid glycosides etc. The physiological role of the glycosyl and structure-activity relations (SAR) in the glycosidic moiety (-ies) are discussed.

Animals↗
PubMed2001

Pregnane glycoside, lignan glycosides, triterpene glycosyl ester and flavonoid glycosides from Rubus amabilis.

Two new compounds, 3-O-beta-D-glucopyranosyl-3 beta, 15 alpha-dihydroxypregn-5-en-20-one (1) and (-)-secoisolariciresinol-O-alpha-L-rhamnopyranoside (2), along with six known compounds (3-8), have been isolated from the aerial parts of Rubus amabilis Focke. The structures of the new compounds were elucidated mainly by spectroscopic methods and some chemical transformations.

Drugs, Chinese Herbal↗
PubMed2004

Interference of Uzara glycosides in assays of digitalis glycosides.

OBJECTIVE: Presentation of a case report and pharmacokinetic investigation in healthy volunteers on the potential interference between cardiac glycosides and glycosides of Uzara, a herbal antidiarrheal preparation. METHODS: Pharmacokinetic pilot investigation of apparent digitoxin and digoxin serum concentrations in 4 healthy volunteers after single-dose administration of 30 drops Uzara (approximately 1.5 ml approximately = 22 mg glycosides). RESULTS: Maximal apparent serum concentrations of digitoxin between 198.0 microg/l and 919.8 microg/l (therapeutic range: 10-25 microg/l) occurred at 4-8 hours after administration. The terminal half-life of the glycosides was 8.87 +/- 2.20 hours. For digoxin, maximal apparent serum concentrations ranged between 1.4 microg/l and 6.34 microg/l (therapeutic range: 0.9-2.0 microg/l) at 6 hours post dosing. CONCLUSIONS: Administration of a single dose of an Uzara preparation, an over-the-counter product, results in false high serum concentrations of digitoxin and digoxin. As described in the manufacturers Summary of Product Characteristics, this preparation should not be given to patients with cardiac failure or arrhythmia who require treatment with cardiac glycosides because of the demonstrated pharmacological actions of uzara glycosides.

Adult↗
PubMed2004

[Cardiac glycosides: From ancient history through Withering's foxglove to endogeneous cardiac glycosides].

For centuries, drugs that increase the power of contraction of the failing heart have been used for the treatment of congestive heart failure (dropsy). The cardiac effect is due to the content of cardiac glycosides. Squill or sea onion, Urginea (Scilla) maritima, a seashore plant, was known by the ancient Romans and Syrians and possibly also by the ancient Egyptians. Squills were used erratically, but some prescriptions indicate that they may have been used for the treatment of oedematous states. The toxic effect of strophanthus species was known from poisoned arrows used by the natives in Africa. Digitalis, derived form the foxglove plant, Digitalis purpurea, is mentioned in writings as early as 1250; a Welsh family, known as the Physicians of Myddvai, collected different herbs and digitalis was included in their prescriptions. However, the druge was used erratically until the 18th century, when William Withering, an English physician and botanist, published a monograph describing the clinical effects of an extract of the foxglove plant. Later, in 1785, the indication and the toxicity of digitalis were reported in his book, "An account of the Foxglove and some of its medical uses with practical remarks on dropsy, and other diseases". In Denmark, the leaves of Digitalis purpurea or Digitalis lanata were tested for cardiac glycoside activity. The standardized digitalis powder was used in tinctures, infusions, and tablets. The preparations were included in successive editions of the Danish pharmacopoeia, some of the tinctures already in 1828, i.e. before the standardization of the drug. Isolation of cardiac glycosides from digitalis, strophanthus and squill and determination of their chemical structures initiated biochemical and pharmacological studies. The scientific advances led to an understanding of cardiac muscle contractility and the Na,K pump as the cellular receptor for the inotropic action of digitalis. Examination of putative endogenous ligands to the receptor revealed some endogenous cardiac glycosides of similar or identical structures as those found in digitalis, strophanthus and squill. Increased concentrations of these glycosides are found in patients with heart failure. Further investigations are needed to determine whether the secretion of glycosides might be a physiologic response to a diminished cardiac output.

Digitalis↗
PubMed1981

The effect of digitalis glycosides-specific antisera on the binding of the glycosides to (Na+ + K+)-ATPase.

The capability of digitalis glycoside-specific antisera to reverse the glycoside-induced inhibition of (Na+ + K+)-ATPase activity was examined. The antisera-induced reversal of the ATPase inhibition caused by digoxin was considerably slower (k-1 = 0.1177 . 10-3 .S-1) than the reversal caused by dihydrodigoxin and dihydrodigitoxin (k-1 = 4.462 . 10-3 . S-1 and K-1 = 3.609 .10-3 . S-1, respectively). In addition, the dissociation rate constants of the ouabain-induced dissociation of the various glycosides from the glycoside-ATPase complex were determined: The dissociation rate constants of the antisera-induced restoration of enzyme activity and that of the ouabain-induced dissociation of glycosides from the glycoside-enzyme complex were not significantly different.

Animals↗
PubMed1996

Thermospray-LC-MS analysis of various groups of polyphenols in tea. I. Catechins, flavonol O-glycosides and flavone C-glycosides.

This paper describes the application of thermospray-HPLC-MS (buffer ionization mode, single-stage MS, positive ion detection) to the analysis of flavanols (catechins), flavonol O-glycosides, flavone C-glycosides as well as caffeine, theobromine, theogallin and theanine from tea. All compounds are detected as pseudo-molecular ions [M+H]+. Other molecular ion species are adducts with sodium, potassium, ammonium and solvent clusters. The catechin gallates and the flavonol glycosides are fragmented. The fragmentation is temperature dependent. The glycoside bond is labile and consequently the flavonol glycosides have the protonated aglycone as this base peak. The ester bonds in the catechin gallates are more stable and the fragmentation is limited. The fragment pattern contributes to the structural information. LC-thermospray-MS is a good analytical tool for identifying the polyphenols mentioned above both in tea and other foodstuffs, especially in method development and structural elucidation.

Carbohydrate Sequence↗
PubMed2001

Analysis of glycosidically bound aroma precursors in tea leaves. 3. Change in the glycoside content of tea leaves during the oolong tea manufacturing process.

A direct qualitative and quantitative determination of the glycosides of tea aroma compounds at the four stages of the oolong tea manufacturing process (plucking, solar withering, indoor withering, and oolong tea product) was carried out by a capillary gas chromatographic-mass spectrometric analysis after trifluoroacetyl derivatization of the glycosidic fractions. Sixteen glucosides and primeverosides were identified and quantified in cv. Chin-shin-oolong and cv. Chinhsuan-oolong. A comparison of the glycosides in dried fresh leaves between the two cultivars showed significant differences. During the manufacturing process, the amounts of most of these glycosides increased from the solar-withering stage, reaching the highest level at the final stage of oolong tea production. It was noted that no glycoside decreased in its content during the manufacturing process, this being quite different from the manufacture of black tea. In addition, the contents of these alcoholic aroma compounds in the free aroma concentrate from each cultivar remained almost unchanged or slightly decreased, and they constituted only about 12 and 17% in amount of the whole oolong tea aroma compounds. However, jasmine lactone and indole were markedly higher in the final oolong tea products.

Chromatography, Gas↗
PubMedDate not supplied

[N-acetylmuramyl-L-alanyl-D-isoglutamine glycosides. Effect of glycoside center configuration and aglycone nature on biological activity].

Hexyl, octyl, and cyclohexyl beta-glycosides and heptyl and cyclohexyl alpha-glycosides of muramyl dipeptide (MDP) were synthesized. Tests in vitro and in vivo revealed lower immunostimulating activities of MDP alpha-glycosides in comparison with the corresponding beta-glycosides and MDP itself. In the case of alkyl beta-glycosides, differences in hydrocarbon chain lengths (C4-C8) and in aglycone (aliphatic chain and aliphatic or aromatic ring) exerted no substantial effect on the immunostimulating activity.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed2001

Analysis of glycosidically bound aroma precursors in tea leaves. 2. Changes in glycoside contents and glycosidase activities in tea leaves during the black tea manufacturing process.

Glycosides are known to be precursors of the alcoholic aroma compounds of black tea. They are hydrolyzed by endogenous glycosidases during the manufacturing process. Changes in the amounts of these glycosides during the manufacturing process were investigated by using a capillary gas chromatographic--mass spectrometric analysis after trifluoroacetyl derivatization of the tea glycosidic fractions. Primeverosides were 3-fold more abundant than glucosides in fresh leaves, but they decreased greatly during the manufacturing process, especially during the stage of rolling. After the final stage of fermentation, primeverosides had almost disappeared, whereas glucosides were substantially unchanged. These results show that hydrolysis of the glycosides mainly occurred during the stage of rolling and confirm that primeverosides are the main black tea aroma precursors. This was also supported by the changes in the glycosidase activities in tea leaves. The glycosidase activities remained at a high level during withering but decreased drastically after rolling.

Fermentation↗
PubMed2005

C-glycosides and aza-C-glycosides as potential glycosidase and glycosyltransferase inhibitors.

Glycosylation as one of most important post-translational modification of gene products is often critical to specific cellular biological functions. Since elevated glycoprocessing enzyme activities have been implicated in the development of various diseases including cancer metastasis, glycosidases and glycosyltransferases are considered as therapeutic targets. Azasugars, the first generation of enzyme inhibitors, have been extensively investigated and two azasugar-based drugs (Miglitol and Miglustat) have been approved. Aza-C-glycosides, molecules with an azasugar core and various C-aglycons attached at the pseudo anomeric center, have the potential to become the second-generation inhibitors with improved specificity and membrane permeability. In this review, C-glycosides, aza-C-glycosides, and aza-C-disaccharides are introduced as glycoprocessing enzyme inhibitors. The synthetic approaches toward those molecules are described based on the key reactions, which include reductive amination, nucleophilic ring opening of epoxides, nucleophilic addition to imines (C=N), and hetero-Michael additions. Aza-C-glycoside-based libraries are also described for the discovery of promising second-generation inhibitors.

Disaccharides↗
PubMed1994

Steroidal glycosides and cardenolide glycosides from Asclepias fruticosa.

Asclepias fruticosa afforded, in addition to five known pregnane glycosides and 11 known cardenolide glycosides, four new pregnane glycosides and eleven new cardenolide glycosides. Structures of these compounds were elucidated by spectroscopic methods and from chemical evidence.

Carbohydrate Sequence↗
PubMed2006

Iridoid glycosides and cucurbitacin glycoside from Neopicrorhiza scrophulariiflora.

Three iridoid glycosides, picrorosides A (1), B (2) and C (3), and a cucurbitacin glycoside, scrophoside A (4), were isolated from the rhizomes of Neopicrorhiza scrophulariiflora (Scrophulariaceae), along with two known iridoid glycosides, picrosides I (5) and II (6), and three known cucurbitacin glycosides (7-9). Their structures were elucidated on the basis of both chemical and spectroscopic data.

Cucurbitacins↗