[o-Nitrophenol-alpha- and-beta-D-glycosides. Use of beta-D-glycosides in the synthesis of alpha-D-glycosides].
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Glycosides↗
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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↗
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↗
[Combined treatment of the aging heart using digitalis-convalloria glycosides. Increase of tolerance of digitalis glycosides through combined treatment with convallaria glycosides].
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Aged↗
[Anthraquinone and anthraquinone glycosides; the synthesis of Chrysazinhydroquinone-1-glycoside and chrysazin-9-anthrone-1-glycoside].
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Anthracenes↗
[On phenol glycosides of salices. 5. Studies on glycoside spectra and the glycoside content of types of salix in central Germany].
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Glycosides↗
[The phenol glycosides of salicaceous plants. 4. Review of newly isolated glycosides and new work on structural information; proof and determination of new glycosides].
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Chemical Phenomena↗
[The phenol glycosides of salicaceous plants. 6. Studies on seasonal changes in glycoside concentrations, on the dependency of glycoside content on the time of day and age of the plant organs].
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Aging↗
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↗
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↗
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↗
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↗
[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↗
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↗
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↗
Two chromone-secoiridoid glycosides and three indole alkaloid glycosides from Neonauclea sessilifolia.
From the dried roots of Neonauclea sessilifolia, two new chromone-secoiridoid glycosides, sessilifoside and 7"-O-beta-D-glucopyranosylsessilifoside, and three novel indole alkaloid glycosides, neonaucleosides A, B, and C, were isolated along with the main known glycosides, 5-hydroxy-2-methylchromone-7-O-beta-D-apiofuranosyl-(1-->6)-beta-D-glucopyranoside, sweroside, loganin, grandifloroside, and quinovic acid 3 beta-O-beta-D-quinovopyranoside-28-O-beta-D-glucopyranoside. The structures of these new glycosides were determined by spectroscopic and chemical means. Neonaucleoside A and its C-3 epimer were prepared from secologanin and tryptamine.
Glycosides↗
Application of directly coupled HPLC-NMR-MS to the identification and confirmation of quercetin glycosides and phloretin glycosides in apple peel.
Directly coupled HPLC-NMR-MS was used to identify and confirm the presence of quercetin O-glycosides and phloretin O-glycosides in an extract of apple peel. From the MS and MS/MS data, the molecular weights of the intact molecules as well as those of quercetin and phloretin and their sugar moieties were deduced. The NMR data provided information on the identity of the compounds as well as the alpha and beta conformations and the position of the glycosides on quercetin and phloretin. The following O-glycosides of quercetin could be identified: quercetin-3-alpha-L-rhamnosyl-(1-->6)-beta-D-glucoside (rutin), quercetin-3-beta-D-galactoside (hyperin), quercetin-3-beta-D-glucoside (isoquercitrin), quercetin-3-beta-D-xyloside (reynoutrin), quercetin-3-alpha-L-arabinofuranoside (avicularin), and quercetin-3-alpha-L-rhamnoside (quercitrin). Phloretin was present as phloretin-2'-beta-D-glucoside (phloridzin) and the 2'-beta-D-xylosyl-(1-->6)-beta-D-glucoside. Concentrations were between 0.2 and 5 mg/g of apple peel.
Chromatography, High Pressure Liquid↗
Cardiac glycosides. 7. Sugar stereochemistry and cardiac glycoside activity.
Digitoxigenin alpha-L-, beta-L-, alpha-D-, and beta-D-glucosides; alpha-L-, beta-L-, alpha-D-, and beta-D-mannosides; and alpha-L- and beta-L-rhamnosides were stereoselectively synthesized from the corresponding sugar tetrabenzyl trichloroacetimidates. The Na+,K+-ATPase receptor inhibitory activities of these glycosides (as a measure of receptor binding) were compared with those of digitoxigenin, digitoxigenin 6'-hydroxy-beta-D-digitoxoside, digitoxigenin beta-D-galactoside, and digitoxigenin beta-D-digitoxoside. The observed activities reveal that a given sugar substituent may have a role in binding of some glycoside stereoisomers, but not others. With alpha-L- and possibly beta-L-rhamnosides, the 5'-CH3 and 4'-OH appear to have a predominant role in binding to the Na+,K+-ATPase receptor. Addition of a 6'-OH to form the corresponding mannosides dramatically disrupts the effect of both the 5'-CH3 and 4'-OH in prompting receptor binding of the alpha-L isomer. However, with the beta-L isomer, some influence of 4'-OH, 3'-OH, and 2'-OH binding remains. With beta-D-glycosides, binding via the "5'-CH3 site" appears to be of little importance and addition of a 6'-OH diminishes activity only slightly. With these beta-D-glycosides, an equatorial 4'-OH, axial 3'-OH, and equatorial 2'-OH groups appear to contribute to binding.
Cardiac Glycosides↗