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PubMed2005

Antifungal activity of steroidal glycosides from Yucca gloriosa L.

The antifungal activity of a crude steroidal glycoside extract from Yucca gloriosa flowers, named alexin, was investigated in vitro against a panel of human pathogenic fungi, yeasts as well as dermatophytes and filamentous species. The minimal inhibitory concentration (MIC) was determined by an agar dilution method. Alexin had a broad spectrum of antifungal activity, found to reside entirely in the spirostanoid fraction. The major tigogenyl glycosides, yuccaloeside B and yuccaloeside C, exhibited MICs between 0.39 and 6.25 microg[sol ]mL for all the tested yeast strains except for two (C. lusitaniae and C. kefyr). They were also active against several clinical Candida isolates known to be resistant to the usual antifungal agents. The MICs for the dermatophytes were between 0.78 and 12.5 microg[sol ]mL. The most sensitive filamentous species was A. fumigatus (MIC = 1.56 microg[sol ]mL). For most of the strains, the MICs of both glycosides were similar to those of the reference antifungal agent.

Antifungal Agents↗
PubMed2005

Structure-activity relationship for antiinflammatory effect of luteolin and its derived glycosides.

Luteolin and its derived glycosides such as a cynaroside, cesioside, isoorientin and stereolensin have been isolated and identified from different kinds of plant species. A (13)C NMR spectroscopic analysis of stereolensin has been done for the first time. These structurally related flavonoids were examined in vitro for their abilities to inhibit enzymes for the synthesis of thromboxane B(2) and leukotriene B(4) as well as hydrogen peroxide scavenging activity. Luteolin exhibited a high inhibitory activity against both thromboxane and leukotriene synthesis. In particular, a remarkable inhibitory effect was observed against leukotriene enzyme activity. The glycosides, cynaroside and cesioside, possessed a moderate inhibition activity against both enzyme synthesis pathways, while isoorientin and stereolensin exhibited selectively good activity against thromboxane synthesis. All the flavonoids showed excellent scavenging activity for the hydrogen peroxide at all the concentrations tested. The results demonstrated that the reactivities of luteolin and its related glycosides against arachidonic acid synthesis and hydrogen peroxide scavenging are dependent on their molecular structures. The presence of ortho-dihydroxy groups at the B ring and OH substitution pattern at C-5 position of the A ring could significantly contribute to the antiinflammatory and antioxidant activities of flavonoids.

Animals↗
PubMed2004

Characterization of acylated flavonoid-O-glycosides and methoxylated flavonoids from Tagetes maxima by liquid chromatography coupled to electrospray ionization tandem mass spectrometry.

Liquid chromatography coupled to negative electrospray ionization (ESI) tandem mass spectrometry (MS/MS) employing a triple quadrupole mass spectrometer was used in the structural determination of acylated flavonoid-O-glycosides and methoxylated flavonoids occurring in Tagetes maxima. The compounds were identified by experiments in full scan mode (MS), and tandem mass experiments (MS/MS) of precursor ion scan, product ion scan, and neutral loss scan modes. In order to characterize the aglycones of the flavonoid glycosides, in-source fragmentation of the deprotonated molecule [M-H]- followed by product ion scan of the resulting aglycone [A-H]- were performed. This combined approach allowed the identification of 51 phenolic compounds, including flavonoid-O-glycosides acylated with galloyl, protocatechuoyl, coumaroyl or caffeoyl groups, methoxylated flavonoids, and hydroxycinnamic acid and phenolic acid derivatives, none of them previously reported in Tagetes maxima.

Chromatography, High Pressure Liquid↗
PubMed2005

Structural characterization of flavonol di-O-glycosides from Farsetia aegyptia by electrospray ionization and collision-induced dissociation mass spectrometry.

This study reports the application of mass spectrometric methods to characterize unknown flavonoids of the herb Farsetia aegyptia Turra (Crucifereae). High-performance liquid chromatography was performed in combination with UV-photodiode array detection (LC/UV-DAD) and electrospray ionization mass spectrometry (LC/ESI-MS) in both positive and negative ion modes. Collision-induced dissociation (CID) mass spectral data were obtained off-line by nanospray (nano-ESI) analysis, which provided a wealth of information and led to the structural proposal of the flavonol di-O-glycosides present in the herb extract. In addition to the mass spectral data, we also report NMR data for the major compound which allowed the completion of its structural elucidation. The Farsetia aegyptia Turra herb extract was found to contain three flavonol di-O-glycosides containing a monosaccharidic residue linked to the 3-O position and a disaccharidic residue linked to the 7-O position; the major compound was characterized as the new flavonoid, isorhamnetin 3-O-alpha-L-arabinoside 7-O-[beta-D-glucosyl-1 --> 2]-alpha(L)rhamnoside. Different types of CID spectra, i.e., low-energy [M+H]+, [M+Na]+ and [M--H]- spectra as well as high-energy [M+Na]+ spectra, were evaluated with respect to their utility to locate the O-linked saccharidic residues in flavonol di-O-glycosides and to determine the sequence in the disaccharidic part. In agreement with previously published data, the 3-O-glycosyl residue was more readily lost from the protonated molecule than the 7-O-glycosyl residue. The opposite behavior was noted for the fragmentation of the deprotonated and sodiated molecules. Radical ions were observed in the high-energy [M+Na]+ CID spectra which provided supporting information on the glycosylation positions.

Brassicaceae↗
PubMed1984

Cardiac glycosides and intracellular Na+, K+, Ca2+.

From the fact that cardiac glycosides exert their positive inotropy most likely via a concentration-dependent inhibition of the Na+/K+-activated ATPase, a membrane-bound enzyme regulating the intracellular potassium and sodium homeostasis, one might assume that intracellular electrolyte changes may be easily detectable. Just the opposite holds true. In the literature there are very conflicting observations depending on the experimental model, the analytical method used etc. At the moment, nevertheless, there is great body of evidence that if the cardiac glycoside inotropy is mediated by an inhibition of Na+/K+-activated ATPase this is not accompanied by a measurable alteration of intracellular ionic composition. On the other hand toxic concentrations of cardiac glycosides significantly produce a loss of cellular potassium and a rise of cellular sodium and calcium content, especially if arrhythmias are present. The increase of intracellular free and bound calcium, which manifests itself functionally as contracture, is believed to be caused at least by two mechanisms: a stimulation of the Na-Ca-exchange and an inhibition of the specific Ca2+-activated ATPase in the plasma membrane catalyzing the uphill Ca2+ outward transport. In vitro studies show that this process is impeded by a local rise of the sodium ion concentration. As the determination of myocardial ion fluxes and cellular electrolyte content has its experimental limitations, further insight may be gained by new techniques which give an answer about possible changes of the electrolyte balance at the subcellular level.

Animals↗
PubMed1984

Therapeutic range of cardiac glycosides.

The narrow therapeutic range of cardiac glycosides continually challenges chemists to synthetize new derivatives with improved therapeutic properties. One of the best investigated semi-synthetic glycosides is 16 alpha-gitoxin. Compared to ouabain and gitoxin, it produces positive inotropic effects on the isolated guinea-pig heart in a wider range of concentrations and causes less pronounced rhythmic disturbances. These results were confirmed by electrophysiological investigations in isolated fibres of the canine myocardium and of the Purkinje system, by investigations in the anaesthetized cat and dog and in healthy volunteers. The effects of various semi-synthetic compounds (e.g. actodigin, ASI-222) are described and possibilities to trigger these effects are discussed. Of some significance seem to be differences in the structure of the (Na+ + K+)-ATPase system of different tissues, e.g. the working muscle and the Purkinje system of the heart, as well as differences due to the formation and dissociation of the glycoside-enzyme complex. The significance of K+, Ca2+ and of several pharmacokinetic parameters (e.g. the volume of distribution) for these reactions are briefly discussed.

Animals↗
PubMed1977

Bilary and urinary excretion of five cardiac glycosides and its correlation with their physical and chemical properties.

Biliary and urinary excretion of five tritium-labelled cardiac glycosides, i.e. Ouabain, K-strophanthoside, Digoxin, Digitoxin and Deslanatoside C, were investigated in anaesthetized guinea-pigs 5 h after i.v. or enteral administration. Urinary excretion is the main route of elimination in the case of Ouabain and Deslanatoside C. Conversely, biliary excretion is predominant in the case of Digoxin and Digitoxin. K-strophanthoside is excreted both via bile and urine. In conscious guinea-pigs treated i.v. with the same cardiac glycosides the highest levels were observed in urine, bile, kidneys and liver. The relative values of those levels were in agreement with the excretion pattern observed in anaesthetized animals. An inverse linear relation (P less than 0.05) was encountered between biliary excretion rate and polarity of glycoside molecula. This correlation has been previously observed by other authors in other species, but not in the rabbit. This suggests that the correlation may not be considered generally applicable at present.

Animals↗
PubMed1977

Absorption and metabolism in man of 16-epi-gitoxin, a new semi-synthetic cardioactive glycoside.

The pharmacokinetics of 3H-16-epi-gitoxin have been investigated after oral administration: The peak serum level occurred after 30-60 min, and its subsequent decline was in two phases with half-lives of 3.5 and 19.5 h, respectively. Within 3 days 66-70% of the administered radioactivity were eliminated by renal excretion. In the first 16 h 15% of excreted activity was in metabolites, but thereafter the glycoside was excreted in unchanged form. The metabolites were characterized by thin-layer chromatography and radio-scanning; it is assumed that they correspond to the bis- and monodigitoxosides as well as to the genin of 16-epi-gitoxin. The unusual pharmacokinetics of the glycoside are discussed in relation to its special kinetics at the molecular level, i.e. the rapid dissociation rate of the glycoside-(Na+ + K+)-ATPase-complex.

Adult↗
PubMed1993

Determination of flavone C-glycosides in tea.

An HPLC method for the determination of flavone C-glycosides (FCG) from black tea has been developed. Sample clean-up was accomplished by means of polyamide column chromatography, followed by enzyme hydrolysis of interfering compounds such was flavonol glycosides and a second polyamide column chromatographic step. Using HPLC with gradient elution and photodiode array detection eight FCG were separated. Seven FCG were isolated by means of preparative HPLC. Identification was carried out using co-chromatography, FAB(Fast Atom Bombardment)-mass spectrometry and various nuclear magnetic resonance techniques. Apigenin 6-C-glucosyl-8-arabinoside (schaftoside) and apigenin 6-C-arabinosyl-8-C-glucoside (isoschaftoside) as well as luteolin 8-C-glucoside (orientin) and luteolin 6-C-glucoside (isoorientin) have been detected in tea for the first time. Three of the other compounds have been identified as apigenin 8-C-glucoside (vitexin), apigenin 6-C-glucoside (isovitexin) and apigenin 6,8-di-C-glucoside (vicenin-2). Their occurrence in tea has been previously reported. From its UV spectrum another compound was concluded to be an apigenin glycoside. The FCG were quantified in a variety of teas of different origins (16 black, two green and one oolong). The total amounts of the FCG were 0.48-2.69 g/kg dry weight. The FCG pattern of teas of different origins were similar to each other and no origin-dependent characteristics have yet been observed. Small amounts of FCG (1.2-2.2 mg/kg) were detected in hydrolysates of high relative molecular mass fractions (Mr > 5000) of a black tea liquor.

Apigenin↗
PubMed1978

[Flavonol glycosides of apples (Malus silvestris Mill.). 10. Phenolics of fruits (author's transl)].

The flavonol glycosides of apple skin (Malus silvestris Mill. cv. Golden Delicious) were separated by means of cellulose column chromatography and paper chromatography, and the following compounds were obtained crystalline and identified by usual procedures: quercetin 3-O-alpha-D-galactoside, quercetin 3-O-xyloside, quercetin 3-O-alpha-L-arabinofuranoside, quercetin 3-O-rhamnoside and rutin. Quercetin 3-O-beta-D-glucoside also was identified, but could not be obtained crystallin. A comparison by TLC of 10 very different varieties of apples namely Golden Delicious, Cox Orange, Roter Berlepsch, Cortland, Ingrid Marie, Jonathan, Boskoop, Laxtons Superb, Gloster, and James Grieve demonstrated the same flavonol glycosides and thus showed no distinctions in glycosid pattern between the different varieties of these apples.

Chromatography, Paper↗
PubMed2005

Hepatoprotective effect of flavonol glycosides rich fraction from Egyptian Vicia calcarata Desf. against CCl4-induced liver damage in rats.

The hepatoprotective activity of flavonol glycosides rich fraction (F-2), prepared from 70% alcohol extract of the aerial parts of V. calcarata Desf., was evaluated in a rat model with a liver injury induced by daily oral administration of CCl4 (100 mg/kg, b.w) for four weeks. Treatment of the animals with F-2 using a dose of (25 mg/kg, b.w) during the induction of hepatic damage by CCl4 significantly reduced the indices of liver injuries. The hepatoprotective effects of F-2 significantly reduced the elevated levels of the following serum enzymes: alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP) and lactate dehydrogenase (LDH). The antioxidant activity of F-2 markedly ameliorated the antioxidant parameters including glutathione (GSH) content, glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), plasma catalase (CAT) and packed erythrocytes glucose-6-phosphate dehydrogenase (G6PDH) to be comparable with normal control levels. In addition, it normalized liver malondialdehyde (MDA) levels and creatinine concentration. Chromatographic purification of F-2 resulted in the isolation of two flavonol glycosides that rarely occur in the plant kingdom, identified as quercetin-3, 5-di-O-beta-D-diglucoside (5) and kaempferol-3, 5-di-O-beta-D-diglucoside (4) in addition to the three known compounds identified as quercetin-3-O-alpha-L-rhamnosyl- (1-->6)-beta-D-glucoside [rutin, 3], quercetin-3-O-beta-D-glucoside [isoquercitrin, 2] and kaempferol-3-O-beta-D-glucoside [astragalin, 1]. These compounds were identified based on interpretation of their physical, chemical, and spectral data. Moreover, the spectrophotometric estimation of the flavonoids content revealed that the aerial parts of the plant contain an appreciable amount of flavonoids (0.89%) calculated as rutin. The data obtained from this study revealed that the flavonol glycosides of F-2 protect the rat liver from hepatic damage induced by CCl4 through inhibition of lipid peroxidation caused by CCl4 reactive free radicals.

Animals↗
PubMed2006

A male gift to its partner? Cyanogenic glycosides in the spermatophore of longwing butterflies (Heliconius).

Males of several insect species transfer nuptial gifts to females during mating, typically in the form of a protein-rich spermatophore. In chemically defended species, males could potentially enhance such a gift with chemicals that help protect the female, her eggs, or both. This was shown for lepidopteran species that accumulate pyrrolizidine alkaloids. Most Heliconius butterflies are presumably protected from predators by virtue of de novo synthesized and/or sequestered cyanogenic glycosides. Males of Heliconius species are known to transfer nutritional gifts to the females but whether defensive chemicals could also be transferred is not known. To ascertain whether transfer of cyanogens occurs, we dissected freshly mated females from nine different Heliconius species and analyzed spermatophores for cyanogenic glycosides. We found cyanogens in the spermatophores of all nine species. This is the first time cyanogenic glycosides are reported in the spermatophores of arthropods. We discuss the implications of these findings for Heliconius biology and for other cyanogenic insects as well. We suggest that chemically defended species commonly lace their nuptial gifts with defensive chemicals to improve gift quality.

Animals↗
PubMed2006

Occurrence of iridoid glycosides in in vitro cultures and intact plants of Scrophularia nodosa L.

Shoot, root, and callus cultures of Scrophularia nodosa L. (Scrophulariaceae) were established and cultivated in vitro. Iridoid glycosides, such as harpagoside, aucubin, and catalpol were identified by LC-ESI-MS and their contents determined by HPLC. For comparison intact plants of S. nodosa were analysed. In shoot cultures slightly lower amounts of detectable iridoid glycosides (4.36% dry weight) were determined than in the field grown plants (4.88%). Concentration of harpagoside was highest in leaves of field plants (1.05%) and in flowers of in vitro plantlets (1.10%). For aucubin the highest amount was found in the leaves of in vitro plantlets (1.67%) whereas the levels of aucubin in the leaves of field plants were remarkably lower. Catalpol was produced as a trace compound in intact plants and shoot cultures. Callus and root cultures were apparently not able to synthesise iridoid glycosides.

Culture Media↗
PubMed2005

Floxuridine amino acid ester prodrugs: enhancing Caco-2 permeability and resistance to glycosidic bond metabolism.

PURPOSE: The aim of this study was to synthesize amino acid ester prodrugs of 5-fluoro-2'-deoxyuridine (floxuridine) to enhance intestinal absorption and resistance to glycosidic bond metabolism. METHODS: Amino acid ester prodrugs were synthesized and examined for their hydrolytic stability in human plasma, in Caco-2 cell homogenates, and in the presence of thymidine phosphorylase. Glycyl-L: -sarcosine uptake inhibition and direct uptake studies with HeLa/PEPT1 cells [HeLa cells overexpressing oligopeptide transporter (PEPT1)] were conducted to determine PEPT1-mediated transport and compared with permeability of the prodrugs across Caco-2 monolayers. RESULTS: Isoleucyl prodrugs exhibited the highest chemical and enzymatic stability. The prodrugs enhanced the stability of the glycosidic bond of floxuridine. Thymidine phosphorylase rapidly cleaved floxuridine to 5-fluorouracil, whereas with the prodrugs no detectable glycosidic bond cleavage was observed. The 5'-L: -isoleucyl and 5'-L: -valyl monoester prodrugs exhibited 8- and 19-fold PEPT1-mediated uptake enhancement in HeLa/PEPT1 cells, respectively. Uptake enhancement in HeLa/PEPT1 cells correlated highly with Caco-2 permeability for all prodrugs tested. Caco-2 permeability of 5'-L: -isoleucyl and 5'-L: -valyl prodrugs was 8- to 11-fold greater compared with floxuridine. CONCLUSIONS: Amino acid ester prodrugs such as isoleucyl floxuridine that exhibit enhanced Caco-2 transport and slower rate of enzymatic activation to parent, and that are highly resistant to metabolism by thymidine phosphorylase may improve oral delivery and therapeutic index of floxuridine.

Amino Acids↗
PubMed2006

Astonishing diversity of natural surfactants: 7. Biologically active hemi- and monoterpenoid glycosides.

This review article presents 90 hemi- and 188 monoterpenoid glycosides, isolated and identified from plants and microorganisms, that demonstrate different biological activities. These natural bioactive glycosides are good prospects for future chemical preparations from these compounds as antioxidants and as anticancer, antimicrobial, and antibacterial agents. These glycosidic compounds have been subdivided into several groups, including hemiterpenoids; acyclic, monocyclic, and bicyclic monoterpenoids; and iridoid monoterpenoids.

Biological Products↗
PubMed1997

Linear, steroidal, and triterpene esters, and steryl glycosides from Festuca argentina.

Ester waxes and steryl glycosides of the grass Festuca argentina were studied. Saponification of the waxes from the petroleum ether extract led to n-hexacosanol as the major single linear alcohol, along with pentacyclic triterpenols, such as beta-amyrin, germanicol, isobaurenol, lupeol, hopenol-a and hopeol, and low amounts of sterols, such as cholesterol, campesterol, stigmasterol, sitosterol and dihydrositosterol, identified by gas chromatography/mass spectrometry (GC/MS). Fatty acids were identified as methyl esters as C12:0, C14:0, C16:0, C18:0, C18:2, and C20:0. The occurrence of a wide chainlength range of fatty acids and a single linear alcohol closely matched for other reports on the tribe Festuceae. On the contrary, pentacyclic triterpenols with a variety of skeletons, especially isobauerenol, are not usual as esters of fatty acids in the Gramineae. Low amounts of steryl glycosides were also obtained from the methylene chloride percolate of the methanol extract. Upon acetylation followed by hydrolysis, aglycones were identified by capillary gas-liquid chromatography (GLC) and GC/MS. As delta 7-cholesterol, campesterol, stigmasterol, sitosterol, dihydrositosterol, and the sugars as glucose, xylose, and arabinose by GLC of the respective alditol acetates. This is the first report on the linear, steryl, and triterpenyl esters of F. argentina. It is noteworthy that delta 7-steryl glycosides are rare, and steryl monoarabinosides have not been previously reported on the family Gramineae.

Alcohols↗
PubMed1990

Cardiac glycosides and congestive heart failure.

Although the cardiac glycosides are universally acknowledged to be important agents in the drug therapy of advanced congestive heart failure (CHF), their role in the treatment of more moderate CHF, particularly in patients in sinus rhythm, remains controversial. Over the past decade, several randomized clinical trials have been undertaken to help clarify the appropriate use of the cardiac glycosides in these patients. Although the data are not conclusive, the available evidence indicates that digoxin is efficacious and relatively safe in patients with CHF whether given alone or in combination with vasodilators. Ongoing myocardial ischemia, hypokalemia and reduced drug clearance due to renal disease or drug interactions remain the clinical parameters most closely associated with digitalis toxicity. However, the recent introduction and widespread availability of a safe and rapidly effective antidote to digitalis preparations--Fab fragments of antidigoxin antibodies--offers the clinician a greater margin of safety in the use of the cardiac glycosides than has been available in the past.

Digitalis Glycosides↗
PubMed1978

Action of endo-alpha-N-acetyl-D-galactosaminidase on synthetic glycosides including chromogenic substrates.

The synthetic glycosides, p-nitrophenyl- and o-nitrophenyl-2-acetamido-2-deoxy-3-O-beta-D-galactopyranosyl-alpha- D-galactopyranosides, were found to be effective chromogenic substrates for an endo-alpha-N-acetyl-D-galactosaminidase. We did not experience any problems when these substrates were used for the screening of column fractions during the purification of the endoenzyme from Diplococcus pneumoniae culture filtrates. However, it should be pointed out that a combination of exo-beta-galactosidase, capable of cleaving beta 1-->3 linkages, and an exo-alpha-N-acetyl galactosaminidase would also liberate nitrophenol from the above substrates. The enzyme had no action on several other synthetic glycosides tested indicating the strict specificity of this enzyme for the disaccharide Gal beta-->GalNAc linked via an alpha-linkage to the aglycone. The enzyme was inactive when the aglycone was methanol but shows activity against the glycosides of phenol, nitrophenols, serine, and threonine. The use of p-nitrophenyl-2-acetamido-2-deoxy-3-O-beta -D-galactopyranosyl-beta-D-galactopyranoside, which is a competitive inhibitor of the endoenzyme, as an affinity ligand for the purification of the enzyme is described.

Affinity Labels↗