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 361 records · Page 20Linked to original sources
PubMed2001

Effects of cardiac glycosides on 24-h ambulatory blood pressure in healthy volunteers and patients with heart failure.

Blood pressure effects of cardiac glycosides in humans have been infrequently reported. Although direct infusion of ouabain or digoxin causes vasoconstriction, indirect effects of cardiac glycosides may have the opposite effect, owing to changes in sympatho-vagal balance. This paper summarises three studies on the effects of cardiac glycosides on circadian blood pressure, utilizing automatic 24-h ambulatory blood pressure measurement (ABPM). In healthy volunteers, 10 days of oral digoxin or digitoxin caused decreases in diastolic blood pressure and heart rate during overnight sleep. No effect was detectable during daytime activities. In patients with heart failure (NYHA stage II), 7 days of oral digoxin also caused a decrease in diastolic blood pressure but only a small increase in systolic pressure during overnight sleep. Again, no effect was detectable during the day. Cardiac glycosides have significant effects on blood pressure, which only appear during overnight sleep, i.e. a phase when sympathetic background activity is lowest. Regular daytime activities may 'overwrite' these effects. Effects of cardiac glycosides on blood pressure may have therapeutic impact, depending on the stage of heart failure and concomitant diseases.

Blood Pressure↗
PubMed2004

The type of sugar moiety is a major determinant of the small intestinal uptake and subsequent biliary excretion of dietary quercetin glycosides.

Quercetin is an important dietary flavonoid with putative beneficial effects in the prevention of cancer and CVD. The in vivo bioactivity of quercetin depends on its bioavailability, which varies widely between foods. We used an in situ rat intestinal perfusion model to study whether differential small intestinal hydrolysis of the sugar moiety of five naturally occurring quercetin glycosides determines the small intestinal uptake and subsequent biliary excretion of quercetin. After 30 min perfusion, a decrease of intact quercetin glycoside in perfusate was observed for quercetin-3-O-ss-glucoside (20.9 (sem 1.4) micromol/l) and quercetin-4'-O-ss-glucoside (23.5 (sem 1.6) micromol/l), but not of quercetin-3-O-ss-galactoside, quercetin-3-O-ss-rhamnoside and quercetin-3-O-alpha-arabinopyranoside. Appearance of free quercetin in perfusate and conjugated quercetin metabolites (quercetin, isorhamnetin, and tamarixetin) in portal and peripheral plasma and bile were also significantly greater after treatment with quercetin-3-O-ss-glucoside or quercetin-4'-O-ss-glucoside compared with any of the other glycosides. Thus, the type of sugar moiety is a major determinant of the small intestinal absorption of quercetin glycosides, but the position (3 or 4') of the glucose moiety does not further influence absorption. The poor bioavailability of important dietary quercetin glycosides has implications for their in vivo bioactivities.

Animals↗
PubMed1996

Dietary quercetin glycosides: antioxidant activity and induction of the anticarcinogenic phase II marker enzyme quinone reductase in Hepalclc7 cells.

It has recently been shown by Hollman et al. (Am. J. Clin. Nutr., 62, 1276-1282) that flavonoid glycosides are preferentially absorbed from dietary onions compared to the flavonoid aglycone. In the light of this, we have compared the bioactivities of the two most abundant flavonoid glycosides that we have purified from onions (quercetin-3,4'-diglucoside and quercetin-4'-glucoside) to the quercetin aglycone, and also to the more commonly studied commercially-available flavonoid glycosides, rutin (quercetin-3-rutinoside) and isoquercitrin (quercetin-3-glucoside). Quercetin aglycone was the most effective inducer of the anticarcinogenic phase II marker enzyme, quinone reductase (QR), in mouse Hepalclc7 cells. Of the glycosides, only quercetin-4'-glucoside was able to induce QR activity in this assay. Inhibition of NADPH/iron- and ascorbate/iron-induced lipid peroxidation of human liver microsomes, and the Trolox C-equivalent antioxidant capacity (TEAC), were also measured. The 4'-glycosylation dramatically decreased activity in the 'antioxidant' assays, whereas 3-substitutions produced much smaller changes. These results show that the preferentially-absorbed quercetin glycosides in onions have markedly different biological properties compared with the aglycone.

Animals↗
PubMedDate not supplied

A comparative dose-effect study with cardiac glycosides assessing cardiac and extracardiac responses in normal subjects.

We tested the hypothesis that differences exist in the pharmacodynamic pattern of different cardiac glycosides. We conducted a randomized, placebo-controlled study in normal volunteers and evaluated the effects of weekly increased oral dosing of digoxin (n = 10; from 0.25 to 1.0 mg/day), meproscillarin (n = 10; from 0.5 to 2.0 mg/day), and placebo (n = 5). To determine the glycoside effects, corrected electromechanical systole (QS2c) was used to measure inotropy and the PQ interval to test dromotropy. Red-green discrimination and critical flicker fusion (CFF) assessed visual functions. Subjective complaints were collected using rating lists. Both glycosides dose dependently shortened QS2c and prolonged PQ interval. PQ prolongations over +20 ms occurred in seven of 10 digoxin subjects, in two of 10 meproscillarin, and in one of five placebo. Equi-inotropic response, identified at 12 ms mean QS2c shortening, revealed the relative potency of digoxin to be 2.4 times higher than meproscillarin; this ratio increased to sevenfold for equi-effective negative dromotropic effects at 12 ms mean PQ prolongation. Each drug was associated with a dominant subjective complaint: digoxin with anergy and meproscillarin with diarrhea. Red-green discrimination was better under meproscillarin and CFF was depressed by digoxin. The results indicate that pharmacodynamic differences exist between cardiac glycosides. A differential use of various glycosides should be considered and tested clinically.

Adult↗
PubMed1982

Effect of administration of activated charcoal and fibre on absorption, excretion and steady state blood levels of digoxin and digitoxin. Evidence for intestinal secretion of the glycosides.

The effects of activated charcoal and fibre on absorption and stationary plasma levels of digoxin and digitoxin have been studied. The effect of fibre alone is small but an interactive effect on absorption may occur if fibre and digoxin are ingested simultaneously. Charcoal effectively decreases glycoside absorption even when administered after the glycosides. During maintenance therapy with digoxin or digitoxin, charcoal administration decreased the glycoside plasma levels by 31.2% and 18.3% respectively. It is suggested that even digoxin may have a significant biliary excretion and enterohepatic circulation or that this glycoside has a significant intestinal secretion. The therapeutic implication of this study is that charcoal may be of value, not only in the management of acute glycoside poisoning, but also in some cases of more chronic intoxication.

Adult↗
PubMed1994

Stepwise synthesis of a GalNAc-containing cluster glycoside ligand of the asialoglycoprotein receptor.

A series of peptidylglycoside derivatives, including the tris(GalNAc-aminohexyl) glycoside of tyrosyl(glutamyl)-glutamate (1) which is known to have sub-nanomolar affinity for the asialoglycoprotein receptor (ASGPr), have been synthesized using the protected tetra-O-acetyl aminohexyl glycoside (9) of N-acetylgalactosamine. The N-succinyl derivative of 1 was also prepared, providing a derivative for bioconjugate formation via carboxyl activation of the glycopeptide. Use of the protected glycoside 9 affords synthetic intermediates with increased solubility in organic solvents that are easier to purify and use in subsequent synthetic manipulations in comparison with compounds containing unprotected glycosides. These synthetic procedures will be generally applicable to the preparation of related compounds to probe binding to the ASGPr and the use of these cluster glycosides as ligands for targeted delivery to the liver.

Acetylgalactosamine↗
PubMed1990

Cardiac glycosides and pregnanes from Adenium obesum (studies on the constituents of Adenium. I).

Cardiac glycosides and pregnanes from the roots and the stems of Adenium obesum Roem. et Schult. were investigated. Among 30 cardiac glycosides including 15 known glycosides and 15 new combinations of the known aglycones and sugars, the structures of 11 glycosides were elucidated. Oleandrigenin beta-gentiobiosyl-beta-D-thevetoside was the main glycoside. Neridienone A and 16,17-dihydroneridienone A, common pregnanes in Apocynaceae, were also isolated.

Cardiac Glycosides↗
PubMed1993

Phytochemical studies of seeds of medicinal plants. III. Ursolic acid and oleanolic acid glycosides from seeds of Patrinia scabiosaefolia Fischer.

Three isomeric pairs of ursolic acid (1, 3, and 5) and oleanolic acid (2, 4, and 6) glycosides were isolated as predominant constituents from seeds of Patrinia scabiosaefolia Fischer (Valerianaceae). Based on chemical and spectral evidence, their structures were established to be 3-O-[alpha-L-rhamnopyranosyl-(1-->2)-alpha-L-arabinopyranosyl] ursolic acid (1) and oleanolic acid (2), 3-O-[beta-D-glucopyranosyl-(1-->3)-alpha-L-arabinopyranosyl] ursolic acid (3) and oleanolic acid (4), and 3-O-[alpha-L-rhamnopyranosyl-(1-->2)-[beta-D-glucopyranosyl- (1-->3)]-alpha-L-arabinopyranosyl] ursolic acid (5) and oleanolic acid (6), respectively. Glycosides 1, 5, and 6 are new compounds and named as patrinia-glycosides A-I, B-I, and B-II, respectively. Glycoside 3 is a known but is the first naturally occurring product. Ursolic acid glycosides were first found from this plant specimen.

Carbohydrate Sequence↗
PubMed1994

Syntheses of glycyrrhetic acid alpha-diglycosides and enol alpha-glycosides.

Glycyrrhetinate alpha-monoglycoside derivatives 8, 10 and 12, all having a trichloroacetyl group at the C-2 position of the pyranose ring, were treated with NH3-saturated ether at 0 degrees C to give the corresponding alcohols 13, 15 and 17, accompanied by 2'-chloroderivatives, 14, 16 and 18, respectively. Glycosylations of the alcohols 13, 15 and 17 with methyl 2,3,4-tri-O-acetyl-alpha-D-glucuronatopyranosyl bromide 19 in the presence of AgOTf in dry CH2Cl2 gave the corresponding alpha-diglycosides 20, 22 and 24 together with the enol alpha-glycosides 21, 23 and 25, respectively. Glycosylations of the diglycoside derivatives 20, 22 and 35 having no reactive OH group in the molecules with 19 for longer reaction times gave quantitatively the enol alpha-glycoside derivatives 21, 23 and 36, respectively. Glycosylation of the monoglycoside derivative 37, which has a poorly reactive OH group at the C-4 position on the pyranose ring, with 19 gave an enol alpha-glycoside 38. The mechanism of the formation of enol alpha-glycosides was investigated. Removal of the protecting groups of 20, 22 and 24 by successive treatment with 1.5N NaOMe in MeOH and 5% KOH in EtOH-H2O (1:1) gave the free alpha-diglycosides 26-28, and removal of those of 31, 21, 23, 25 and 36 by treatment with 5% KOH in EtOH-H2O (1:1) under reflux gave the free enol alpha-glycosides 41-45, respectively.

Acetylation↗
PubMed1997

Constituents of a fern, Diplazium subsinuatum. II. Structure elucidation of five new hopane-triterpene glycosides.

From whole fern, Diplazium subsinuatum (Wall. ex Hook. et Grev.) Tagawa, two new hopane-triterpene glycosides named diplaziosides III and IV were isolated, together with three new hopane glycosides with acetylated sugars. The structures of diplaziosides III and IV were established as (22S)-24-O-alpha-L-arabinofuranosyl-(1 --> 2)- [beta-D-glucopyranosyl-(1 --> 6)]-beta-D-glucopyranosyl-20 alpha-O-beta-D-glucopyranosyl-30-hydroxyhopan-28-oic acid (1) and (22R)-24-O-alpha-L-arabinofuranosyl-(1-->2)-[beta-D-glucopyranosyl-(1--> 6)]-beta-D-glucopyranosyl-30-carboxy-17-hydroxy-hopano-28,22-lacto ne (2), respectively, on the basis of spectral evidence. Diplazioside III (1) is novel not only in its glycoside structure, but also in its triterpene structure and moreover, 1 provides the first instance of a naturally occurring bisdesmoside with a hopane aglycone. The structures (3a, 3b, and 4a) of the acetylated glycosides were also elucidated, and this is the first report of naturally occurring acetates of hopane glycosides.

Carbohydrate Sequence↗
PubMed2001

Sweet pregnane glycosides from Telosma procumbens.

An intensely sweet polyoxypregnane glycoside, telosmoside A15 (15), was isolated from an Asian Asclepiadaceae plant, Telosma procumbens, collected in Vietnam. This is the first time a sweet pregnane glycoside has been found, and its sweetness intensity is 1000 times greater than that of sucrose. From the same plant, 17 other new glycosides were isolated, having the same aglycone; they are named telosmosides A1-A14 (1-14) and A16-A18 (16-18). Some of these glycosides are also sweet, but others are tasteless or bitter. Chemical structures of the 18 glycosides were determined, and the structure-taste relationship was discussed.

Glucosidases↗
PubMed1999

Permeation of hesperidin glycosides across Caco-2 cell monolayers via the paracellular pathway.

The intestinal permeability to hesperidin glycosides was investigated by using a cultured monolayer of Caco-2 as a model for the small intestinal epithelium. Hesperidin glycosides were added to the apical side of the monolayer, and the substances that permeated to the basolateral side were determined by HPLC. Whereas hesperidin did not permeate across the Caco-2 monolayer, probably owing to its low solubility, the hesperidin glycosides did permeate. The transepithelial transport of hesperidin glycosides occurred in time- and dose-dependent manners. The transport was observed to be energy-independent, and was inversely correlated with the transepithelial electrical resistance (TEER) of the monolayer. These results suggest that hesperidin glycosides permeate across the Caco-2 cell monolayer via the paracellular pathway.

Caco-2 Cells↗
PubMed2005

Recent advances in aryl C-glycoside synthesis.

Aryl C-glycosides are stable analogs of the corresponding O-glycosides. Because of their favorable pharmacological profiles attributed primarily to the C-glycosyl moiety, aryl C-glycosides have gained increasing popularity as drug candidates. In this review we focus on the synthesis of aryl C-glycosides including puerarin and kendomycin. This review is organized based on the type of chemistry used in the assembly of the C-glycosides with the following sub-sections: electrophilic reaction, cross-coupling reaction, free radical reaction, cyclization, intramolecular O-C rearrangement, umpolung, and miscellaneous reactions.

Carbon↗
PubMed1980

Biosynthesis of anthracycline antibiotics by Streptomyces galilaeus. I. Glycosidation of various anthracyclinones by an aclacinomycin-negative mutant and biosynthesis of aclacinomycins from aklavinone.

An aclacinomycin-negative mutant strain KE303 which required aklavinone aglycone for the production of anthracycline antibiotics was derived from Streptomyces galilaeus, and employed for the glycosidation of various anthracyclinones. epsilon- gamma- and beta-Rhodomycinones, epsilon-isorhodomycinone, epsilon- and beta-pyrromycinones and chemically modified aklavinones were found to be glycosidated to the biologically active anthracyclines, when they were fed to the growing culture. However, the feeding of daunomycinone, 13-deoxydaunomycinone, adriamycinone and steffimycinone did not yield any glycoside. The bioconversion of presumptive precursor glycosides revealed that aclacinomycin A is biosynthesized by the step-wise glycosidation from aklavinone vai aklavin and MA144 S1.

Aclarubicin↗
PubMed2000

Effect of dietary cardiac glycosides on blood pressure regulation in rats.

To investigate the possible physiological significance of dietary cardiac glycosides in blood pressure regulation, the blood pressure of normal Sprague Dawley rats raised on a regular diet, which naturally contains large amounts of Na+-pump inhibitors, was compared with that of rats on a purified synthetic diet, which contains no Na+-pump specific inhibitors, and with that of rats on a synthetic diet supplemented with 10 microg x mL(-1) ouabain or 10 microg x mL- convallatoxin in the drinking water. After 6 weeks on the synthetic diet, the systolic blood pressure in the synthetic diet group was significantly elevated (145 +/- 5 vs. 128 +/- 4 mmHg, P < 0.05). At 10 weeks it reached a plateau (154 +/- 3 vs. 122 +/- 3 mmHg, P < 0.05). Plasma renin activity and Na+ level were significantly higher in animals fed synthetic diets than in the regular diet group (P < 0.01). Administration of either losartan or lisinopril or a switch to a low salt synthetic diet (0.03% sodium) normalized the synthetic diet-induced high blood pressure. Supplementation of the synthetic diet with the cardiac glycosides delayed the onset of the increase in blood pressure for 4 weeks. Plasma aldosterone levels were approximately doubled in the cardiac glycoside-treated groups. Higher plasma Na+ levels and hematocrit values present in the synthetic diet group were normalized by the glycoside supplements. These results suggest that supplemental dietary cardiac glycosides exert bidirectional effects on blood pressure regulation through actions that modulate extracellular fluid and electrolyte balance.

Animals↗
PubMed2004

[New steroid hormone family: endogenous cardiac glycosides and their role in physiologic and pathologic conditions].

In the last two decades extensive study has been carried out on the isolation, identification and biosynthesis of the "endogenous digitalis-like compounds" whose physiological and pathophysiological functions are only starting to be understood. Besides ouabain (strophanthin) and digoxin, four further endogenous cardiac glycosides were isolated and identified so far. These compounds are found in almost all mammalian tissues, including blood plasma and urine, but with the highest concentrations in the adrenal gland, pituitary and hypothalamus. De novo biosynthesis of these glycosides occurs in zona fasciculata cells of adrenal glands, precursors such as progesterone, pregnenolone, and rhamnose increase the synthesis of the ouabain-like immunoreactive material. The secretion of these compounds from the adrenocortical cells are controlled by adrenerg mechanisms, as well as via the renin-angiotensin system. The hydrophobic cardiac glycosides are transported in blood as complexes bound to specific binding globulins. The identified endogenous cardiac glycosides fulfill all the postulated criterions of the hormones, so they represent a new class of steroid hormones. The cardiac glycosides influence the active sodium pump, indirectly the intracellular free calcium concentration and therefore exert a positive inotropic effect on cardiac muscle. Furthermore, in physiological concentrations they can regulate the cell growth and protein synthesis inducing activation of intracellular signal pathways. Under pathological conditions, however, when the concentration of these steroids are high, they play a crucial role in the development of different serious illnesses such as essential hypertension as well as congestive heart failure. Further intensive investigations are needed to clarify some contradictory details accumulated during the last few years in this field.

Cardiac Glycosides↗
PubMed1992

Thermodynamic and kinetic studies on the mechanism of binding of methylumbelliferyl glycosides to jacalin.

The binding of Artocarpus integrifolia lectin (jacalin) to 4-methylumbelliferyl (Meumb)-glycosides, Gal alpha Meumb, Gal beta Meumb, GalNAc alpha Meumb, GalNAc beta-Meumb, and Gal beta 3GalNAc beta Meumb was examined by extrinsic fluorescence quenching titration and stopped flow spectrofluorimetry. The binding was characterized by 100% quenching of fluorescence of Meumb-glycosides. Their association constants range from 2.0 x 10(4) to 1.58 x 10(6) M-1 at 15 degrees C. Entropic contribution is the major stabilizing force for avid binding of Meumb-glycosides indicating the existence of a hydrophobic site that is complementary to their methylumbelliferyl group. The second order association rate constants for interaction of these sugars with lectin at 15 degrees C vary from 8.8 x 10(5) to 3.24 x 10(6) M-1 S-1, at pH 7.2. The first order dissociation rate constants range from 2.30 to 43.0 S-1 at 15 degrees C. Despite the differences in their association rate constants, the overall values of association constants for these saccharides are determined by their dissociation rate constants. The second order rate constant for the association of Meumb-glycosides follows a pattern consistent with the magnitude of the activation energies involved therin. Activation parameters for association of all ligands illustrate that the origin of the barrier between binding of jacalin to Meumb-glycosides is entropic, and the enthalpic contribution is small. A correlation between these parameters and the structure of the ligands on the association rates underscores the importance of steric factors in determining protein saccharide recognitions.

Binding, Competitive↗
PubMed1979

[Effect of triterpene glycosides on plasma membrane permeability for UV-absorbing substances in Saccharomyces carlsbergensis yeast cells].

The effect of triterpene glycosides of cauloside C from Caulophyllum robustum M, stichoposide A from Stichopus japonicus S. and theasaponine from Thea sinensis Z. on permeability of plasmic membranes of Saccharomyces carlsbergensis for UV-absorbing substances was studied. It was found that incorporation of 14C-uridine from the endocellular pool into the yeast acid-insoluble fraction decreased under the effect of the triterpene glycosides as a result of the precursor leakage from the cell into the medium. It was found that the triterpene glycosides stimulated the leakage of the UV-absorbing substances with an absorption maximum at 260 nm from the cells. The maximum membranotropic effect was observed at 30--40 degrees C and in the presence of monovalent potassium, sodium, ammonium and lithium ions in the medium. Cauloside C and theasaponine, pentacyclic glycosides had the highest effect on the permeability at pH 4.8--5.6, while stichoposide A, a tetracyclic glycoside, had the highest effect at pH 7.0.

Cell Membrane Permeability↗