Showing papers on "Glucoside published in 2000"

Cellular uptake of dietary flavonoid quercetin 4'-beta-glucoside by sodium-dependent glucose transporter SGLT1.

Abstract: Although it has been suggested that the intestinal glucose transporter may actively absorb dietary flavonoid glucosides, there is a lack of direct evidence for their transport by this system. In fact, our previous studies with the human Caco-2 cell model of intestinal absorption demonstrated that a major dietary flavonoid, quercetin 4′-β-glucoside, is effluxed by apically expressed multidrug resistance-associated protein-2, potentially masking evidence for active absorption. The objective of this study was to test the hypothesis that quercetin 4′-β-glucoside is a substrate for the intestinal sodium-dependent d-glucose cotransporter SGLT1. Cellular uptake of quercetin 4′-β-glucoside was examined with Caco-2 cells and SGLT1 stably transfected Chinese hamster ovary cells (G6D3 cells). Although quercetin 4′-β-glucoside is not absorbed across Caco-2 cell monolayers, examination of the cells by indirect fluorescent microscopy as well as by HPLC analysis of cellular content revealed cellular accumulation of this glucoside after apical loading. Consistent with previous observations, the accumulation of quercetin 4′-β-glucoside in both Caco-2 and G6D3 cells was markedly enhanced in the presence of multidrug resistance-associated protein inhibition. Uptake of quercetin 4′-β-glucoside was greater in SGLT1-transfected cells than in parental Chinese hamster ovary cells. Uptake of the glucoside by Caco-2 and G6D3 cells was sodium-dependent and was inhibited by the monovalent ionophore nystatin. In both Caco-2 and G6D3 cells, quercetin 4′-β-glucoside uptake was inhibited by 30 mM glucose and 0.5 mM phloridzin. These results demonstrate for the first time that quercetin 4′-β-glucoside is transported by SGLT1 across the apical membrane of enterocytes.

Bioavailabilities of quercetin-3-glucoside and quercetin-4'-glucoside do not differ in humans

Abstract: The flavonoid quercetin is an antioxidant which occurs in foods mainly as glycosides. The sugar moiety in quercetin glycosides affects their bioavailability in humans. Quercetin-3-rutinoside is an important form of quercetin in foods, but its bioavailability in humans is only 20% of that of quercetin-4'-glucoside. Quercetin-3-rutinoside can be transformed into quercetin-3-glucoside by splitting off a rhamnose molecule. We studied whether this 3-glucoside has the same high bioavailability as the quercetin-4'-glucoside. To that end we fed five healthy men and four healthy women (19-57 y) a single dose of 325 micromol of pure quercetin-3-glucoside and a single dose of 331 micromol of pure quercetin-4'-glucoside and followed the plasma quercetin concentrations. The bioavailability was the same for both quercetin glucosides. The mean peak plasma concentration of quercetin was 5.0+/-1.0 micromol/L (+/-SE) after subjects had ingested quercetin-3-glucoside and 4.5+/-0.7 micromol/L after quercetin-4'-glucoside consumption. Peak concentration was reached 37 +/-12 min after ingestion of quercetin-3-glucoside and 27+/-5 min after quercetin-4'-glucoside. Half-life of elimination of quercetin from blood was 18.5+/-0.8 h after ingestion of quercetin-3-glucoside and 17.7+/-0.9 h after quercetin-4'-glucoside. We conclude that quercetin glucosides are rapidly absorbed in humans, irrespective of the position of the glucose moiety. Conversion of quercetin glycosides into glucosides is a promising strategy to enhance bioavailability of quercetin from foods.

Isolation and identification of stilbenes in two varieties of Polygonum cuspidatum.

Abstract: The roots of two varieties of Polygonum cuspidatum (Hu Zhang and Mexican Bamboo) were analyzed for resveratrol and analogues. The roots of each variety were dried and ground into a powder. The powdered roots were then extracted with methanol and ethyl acetate. The ethyl acetate fraction of the Mexican Bamboo was then subjected to fractionation and purification using silica gel column chromatography and semipreparative HPLC. In addition to resveratrol (3,5,4'-trihydroxystilbene), three stilbene glucosides were identified by (1)H NMR, (13)C NMR, and MS. The stilbene glucosides were shown to be a piceatannol glucoside (3,5,3', 4'-tetrahydroxystilbene 4'-O-beta-D-glucopyranoside), resveratroloside (3,5,4'-trihydroxystilbene 4'-O-beta-D-glucopyranoside), and piceid (3,5,4'-trihydroxystilbene 3-O-beta-D-glucopyranoside). The levels of the piceatannol glucoside and piceid were twice as high in the Mexican Bamboo as compared to the Hu Zhang.

Gallic Acid derivatives from mezoneuron benthamianum leaves.

Abstract: The leaves of Mezoneuron benthamianum yielded methyl gallate and gallic acid as the constituents responsible for its antibacterial activity. (-)-Shikimic acid-3-O-gallate, 1-O-methyl-D-chiro-inositol, (-)-epicatechin, (-)-epicatechin-3-gallate and kaempferol-3- (6?-galloyl) glucoside were also isolated. The minimum inhibitory concentrations of these compounds against some Gram-positive and Gram-negative microorganisms and a fungus are presented.

Acylated flavonol glycosides from the flower of Inula britannica.

Abstract: Three new acylated flavonol glycosides, patuletin 7-O-(6' '-isobutyryl)glucoside (1), patuletin 7-O-[6' '-(2-methylbutyryl)]glucoside (2), and patuletin 7-O-(6' '-isovaleryl)glucoside (3), were isolated from the n-BuOH extract of Inula britannica flowers by bioassay-guided fractionation, together with other known flavonoids. The structures were elucidated by 1D and 2D NMR, FABMS, and other spectral analyses. The eight flavonoids, including new compounds (1-3), patulitrin (7), nepitrin (8), axillarin (10), patuletin (11), and luteolin (12), showed profound antioxidant activity in DPPH assay and cytochrome-c reduction assay using HL-60 cell culture system.

Purification and characterization of a hydroxamic acid glucoside β-glucosidase from wheat (Triticum aestivum L.) seedlings.

Abstract: A β-glucosidase (EC 3.2.1.21) with a high affinity for cyclic hydroxamic acid β-d-glucosides was purified from 48-h-old wheat (Triticum aestivum L.) seedlings. The activity occurred transiently at a high level during the non-autotrophic stage of growth, and the nature of the transient occurrence was correlated with that of 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one glucoside (DIMBOA-Glc). The glucosidase had maximum activity at an acidic pH (pH 5.5) and the purified enzyme showed a high affinity for DIMBOA-Glc, Vmax and Km being 4100 nkat/mg protein and 0.27 mM, respectively. It also hydrolyzed p-nitrophenol β-glycosides, as well as flavone and isoflavone glucosides, but to a lesser extent. The results indicated that the primary natural substrate for the glucosidase is DIMBOA-Glc and that the enzyme is involved in defense against pathogens and herbivores in non-autotrophic wheat. The glucosidase was found to be present as oligomeric forms with a molecular mass of 260–300 kDa comprising 60- and 58-kDa monomers. The N-terminal 12-amino-acid sequences of the two monomers were identical (Gly-Thr-Pro-(Ser?)-Lys-Pro-Ala-Glu-Pro-Ile-Gly-Pro), and showed no similarity to those of other plant glucosidases. Polyacrylamide gel electrophoresis under nondenaturing condition indicated the existence of at least eight isozymes. Three cultivars of Triticum aestivum had the same zone of glucosidase activity on zymograms, but the activity zones of the Triticum species, T. aestivum L., T. spelta L. and T. turgidum L., had different mobilities.

Cypellocarpins A-C, phenol glycosides esterified with oleuropeic acid, from Eucalyptus cypellocarpa.

Abstract: Three new phenol glycosides acylated with (+)-oleuropeic acid, cypellocarpins A (1), B (2), and C (3), along with seven known compounds, were isolated from the dried leaves of Eucalyptus cypellocarpa. Structures of the new compounds were determined on the basis of spectroscopic methods, including 2D NMR experiments and chemical degradation. These new compounds and a known related glucoside (7) showed potent in vitro antitumor-promoting activity in a short-term bioassay evaluating the inhibitory effect on Epstein-Barr virus early antigen activation induced by 12-O-tetradecanoyl phorbol 13-acetate (TPA). These compounds also suppressed an in vivo two-stage carcinogenesis induced with nitric oxide and TPA on mouse skin.

Expression of cholesteryl glucoside by heat shock in human fibroblasts

Abstract: We investigated the heat-induced alteration of glycolipids in human cultured cells, TIG-3 fibroblasts, to show the expression of steryl glucoside by heat shock. A glycolipid band was detected on a thin-layer chromatography plate in lipid extracts from TIG-3 cells exposed to high temperature (42°C) for 15 and 30 minutes, while it was hardly detectable without heat shock. Both cholesterol and glucose were almost exclusively detected by gas liquid chromatography as degradation products of the lipid. The structure of the lipid molecule was elucidated by electrospray mass spectrometry to be a cholesteryl glucoside. This is the first report to show the occurrence of a steryl glucoside in mammalian cells, and this substance is considered to have a significant role in heat shock responses in mammalian cells.

Naphthoquinone glucosides of Drosera gigantea from in vitro cultures.

Abstract: From the shoots of Drosera gigantea propagated under in vitro culture, the rare naphthoquinone glucosides droserone (3,5-dihydroxy-2-methyl-1,4-naphthoquinone) and hydroxydroserone (3,5,8-trihydroxy-2-methyl-1,4-napthoquinone) 5-O-beta-glucosides, together with the free naphthoquinones droserone, hydroxydroserone and plumbagin were isolated. The structures of the glucosides and hydroxydroserone were studied by 2D NMR techniques. The glucosides appear to be responsible for the brown-red (maroon) colour of this plant. Of the other naphthoquinones typical for the family Droseraceae only hydroplumbagin glucoside could be detected, whereas the presence of 7-methyljuglone and rossoliside (= 7-methylhydrojuglone glucoside) was excluded.

Isolation and structure determination of new antioxidative ferulic acid glucoside esters from the rhizome of Alpinia speciosa, a Zingiberaceae plant used in Okinawan food culture.

Abstract: An assay-guided isolation gave three antioxidants including two newly identified compounds from the rhizomes of Alpinia speciosa, which is used as an important plant in the food culture of the Okinawa area of Japan. Spectroscopic analysis of the two new compounds revealed them to be new glucoside esters of ferulic acid. The antioxidant activity of the esters was measured using two different methods. Both compounds showed greater activity than that of Trolox in the TLC method; however, one of the compounds showed weaker inhibitory activity than that of Trolox and epicatechin against AMVN-induced methyl linoleate oxidation.

2,4-Dichlorophenoxyacetic Acid Metabolism in Transgenic Tolerant Cotton (Gossypium hirsutum)

Abstract: The metabolic fate of 2,4-dichlorophenoxyacetic acid (2,4-D) was studied in leaves of transgenic 2,4-D-tolerant cotton (Gossypium hirsutum), which is obtained by transfer of the tfdA gene from the bacterium Alcaligenes eutrophus. The tdfA gene codes for a dioxygenase catalyzing the degradation of 2,4-D to 2,4-dichlorophenol (2,4-DCP). [phenyl-14C]-2,4-D was administered by petiolar absorption followed by an 18 h water chase or converted to the isopropyl ester and sprayed onto the leaf surface; the leaves were harvested 48 h later. The herbicide was degraded to 2,4-DCP by the bacterial enzyme expressed in the plants. 2,4-DCP was rapidly converted to more polar metabolites and was never found in detectable amounts. Metabolite structures were deduced from enzymatic hydrolysis studies and mass spectrometric analyses. The first metabolite was the glucoside conjugate of 2,4-DCP (2,4-DCP−β-O-glucoside). The major terminal metabolites were two more complex glucosides: 2,4-DCP−(6-O-malonyl)glucoside and 2,4-DCP−(...

Tryptophan-N-glucoside in fruits and fruit juices.

Abstract: In extracts prepared from various fruits as well as in fruit juices a single tryptophan glycoconjugate was detected by HPLC-MS analysis. Product ion spectra demonstrated the N-glycosidic linkage of a hexose moiety to the indole nitrogen. For structure elucidation, the novel tryptophan glycoside was isolated from pear juice and identified as N1-(β-d-glucopyranosyl-4C1)-l-tryptophan by 1H, HH−COSY and 13C NMR spectroscopy. Finally, we disclosed the biosynthetic origin of the novel tryptophan metabolite by demonstrating the enzymatic glycosylation of deuterium-labeled tryptophan, which was applied to pear fruit. Keywords: Tryptophan-N-glucoside; electrospray ionization; HPLC-MS/MS; biosynthesis

Isolation and investigation of antimicrobial effect of 3,4,3'-tri-O-methylflavellagic acid and its glucoside from Anogeissus leocarpus

Abstract: 3,4,3'-Tri-O-methylflavellagic acid and its glucoside (reported for the first time) were isolated from Anogeissus leocarpus. These compounds were analysed by GC-MS, IR, 1D and 2D-NMR, and also as acetates. Antimicrobial effect of the glucoside on S. aureus, E. coli, Ps. aeruginosa and C. albicans show that it possesses growth inhibitory effect at various concentrations. (Received March 22, 2000; revised October 25, 2000) Bull. Chem. Soc. Ethiop. 2000, 14(2), 169-174

Alkyl glucoside synthesis using Thai rosewood β-glucosidase

Abstract: β-Glucosidase from Thai Rosewood (Dalbergia cochinchinensis Pierre) catalyses transglucosylation of alcohols to synthesise alkyl glucosides. Good yields were obtained with primary alcohols, often approaching 90% in terms of alkyl glucoside, but secondary alcohols gave poorer yields, and tertiary alcohols did not react. The enzyme showed higher transglucosylation yields than almond β-glucosidase with all alcohols tested.

Cardenolides and ${\beta}$-Sitosterol Glucoside from Pergularia tomentosa L.

Abstract: The aerial parts of Pergularia tomentosa L. afforded three cardenolides, desglucouzarin, coroglaucigenin and uzarigenin, in addition to β-sitosterol glucoside. The isolated compounds were identified by physical and spectral means, including IR, UV, [α]_D 1D-, 2D-NMR and FAB-MS experiments. The cardenolides, ghalakinoside, calactin and pergularoside previously reported from roots, were also identified in the aerial parts.

Potential carcinogenic and inhibitory activity of compounds isolated from Lilium candidum L.

Abstract: This paper deals with determination of potential carcinogenic and inhibitory activity of 10 compounds isolated from the ethanolic extract of Lilium candidum L. perfonned by DC polarography. The series of investigated compounds consisted of two spirostanol saponins, two pyroline derivatives, jatropham and its glucoside, flavonol kaempferol, 2-fenylethyl-alpha-L-arabinopyranosyl-(1-->6)-beta-D-glucopyranoside, 2-phenylethylpalmitate and methylsuccinic acid. Carcinogenic, resp. mutagenic activity data for these compounds, with the exception of kaempferol, are not available in scientific literature. All tested compounds were reduced in N,N-dimethylformamide in one or two well defined steps. They also fonned a reversible complex with alpha-lipoic acid, a compound serving as an indicator of carcinogenic activity. The marginal diffuse current values of these complexes served as a criterion of a very low potential carcinogenicity. The inhibitory activity of isolates were studied in the presence of 12-O-tetradecanoylphorbol-13-acetate, a specific tumor promoter for an epidermal carcinogenesis, and in the presence of a polyaromatic substance 7,12-dimetylbenz(a)anthracene known as a carcinogen. The spirostanol saponins possessed the highest inhibitory activity (> 70%) and jatropham (66%). The inhibitory activity of jatropham glucoside was significantly lower (49%). Practically zero inhibitory activity was measured for the 2-phenylethylpalmitate and methylsuccinic acid.

Application of response surface methodology to the study of methyl glucoside polyester synthesis parameters in a solvent-free system.

Abstract: Response surface methodology (RSM) and 3-level-3-factor fractional factorial design were used to evaluate the effects of synthesis parameters, including reaction time (4 to 8 h), temperature (110 t...

A New Acylated Isoflavone Glucoside from Pterocarpus santalinus

Abstract: Phytochemical investigation on the constituents of heartwood of Pterocarpus santalinus resulted in the isolation of a new acylated isoflavone glucoside. The structure of the new compound was elucidated on the basis of spectral studies as 4',5-dihydroxy-7-O-methyl isoflavone 3'-O-D-(3''-E-cinnamoyl)glucoside.

Flavonol glycosides from the leaves of ginkgo biloba

Abstract: AIM Isolation and structural elucidation of the constituents from leaves of Ginkgo biloba . METHODS To isolate chemical constituents, solvent extraction together with column chromatography was used. IR, UV, MS and NMR spectra were employed for structural identification. RESULTS Eight flavonol glycosides were isolated. They were elucidated as quercetin 3 O β D glucoside(1), kaempferol 3 O β D glucoside(2), rutin(3), kaempferol 3 O β D rutinoside(4), isorhamnetin 3 O β D rutinoside(5), quercetin 3 O β D glucosyl(1 2) α L rhamnoside(6), kaempferol 3 O β D glucosyl(1 2) α L rhamnoside(7) and isorhamnetin 3 O β D glucosyl(1 2) α L rhamnoside(8). CONCLUSION Compound 8 was shown to be a new compound.

An iridoid glucoside from Euphrasia pectinata.

Abstract: A new iridoid glucoside, 5β,6β-dihydroxyboschnaloside (1), was isolated from the aerial parts of Euphrasia pectinata. Five known iridoid glucosides, 6β-hydroxyboschnaloside (2), aucubin, euphroside, plantarenaloside, and geniposidic acid, and two known phenylethanoid glycosides, verbascoside (= acteoside) and leucosceptoside A, were also obtained and characterized. The structure of compound 1 was established by spectroscopic evidence.

Tensio-active glucoside urethanes

Abstract: The invention concerns the use as surface-active agent of a glucoside alkyl urethane (I) which is composed of units of the general formula (II): A(O-CO-NH-R)S wherein A represents a glucosyl unit of a starch hydrolysate molecule, the starch hydrolysate having a Dextrose Equivalent (D.E.) ranging from 1 to 47, (O-CO-NH-R) represents an N-alkyl aminocarbonyloxy group replacing a hydroxyl group of the glucosyl unit A, and wherein R represents a linear or branched, saturated or unsaturated alkyl group containing from 3 to 22 carbon atoms, and s represents the number of alkyl carbamate groups per glucosyl unit which number is expressed as degree of substitution (DS) with said DS value ranging from about 0.01 to about 2.0. The invention further relates to novel glucoside alkyl urethanes (I), and a method for their manufacture and to compositions containing one or more of glucoside alkyl urethanes (I). The glucoside alkyl urethanes (I) have good to excellent tensio-active properties in combination with good biodegrability and they are suitable as surfactants for use in household and industrial applications, e.g. as detergents, emulsifiers, emulsion stabilisers, foaming agents, foam stabilisers, dispersants and wetting agents.