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At least 73 records · Page 4Linked to original sources
PubMed1998

Synthesis of cardenolide glycosides and putative biosynthetic precursors of cardenolide glycosides.

A rapid and efficient procedure for glycosylation of steroids was established using a modified Koenigs-Knorr procedure. Peracetylated beta-glycosides were synthesized by reaction of cardenolides, various pregnanes and 23-nor-5,20(22)E-choldienic acid at room temperature with the peracetylated 1-bromo derivatives of D-glucose, D-galactose, D-fucose and cellobiose. Subsequent deprotection was performed by alkaline hydrolysis with sodium methoxide. Structures of the respective glycosides were established by NMR techniques. The complete protocol was shown to be non-destructive at all stages to the sugar moiety and the steroidal nucleus. The gamma-unsaturated lactone ring of the cardenolides was shown to remain intact and no formation of C-14 unsaturated compounds was observed.

Cardenolides↗
PubMed2001

Flavonol glycosides and novel iridoid glycoside from the leaves of Morinda citrifolia.

One new iridoid glycoside and five known flavonol glycosides have been isolated from the leaves of Morinda citrifolia. The new iridoid exists as an epimeric mixture in solution. Complete assignments of the proton and carbon chemical shifts for the individual epimers were accomplished on the basis of high-resolution 1D and 2D NMR data. Their antioxidative activities were measured. All of these compounds showed DPPH free radical scavenging activity at the concentration of 30 microM.

Antioxidants↗
PubMed2000

Triterpene glycosides from the Far-Eastern sea cucumber Pentamera calcigera. 1. Monosulfated glycosides and cytotoxicity of their unsulfated derivatives.

Three new monosulfated triterpene glycosides, calcigerosides B (2), C(1) (3), and C(2) (4), along with the known cucumarioside G(2) (1), have been isolated from the sea cucumber Pentamera calcigera. Their structures have been deduced from extensive spectral analysis (NMR and MS) and chemical evidence. Compounds 2-4 present a novel pentasacharide chain never reported before in sea cucumber triterpene glycosides. The desulfated derivatives of calcigerosides B, C(1), and C(2) (5, 7, and 9, respectively) showed moderate cytotoxicity (IC(50) = 5 microg/mL) against a selection of four human and mouse tumor cell lines.

Animals↗
PubMed2004

2-C-branched glycosides from 2'-carbonylalkyl 2-O-Ms(Ts)-C-glycosides. A tandem SN2-SN2 reaction via 1,2-cyclopropanated sugars.

[reaction: see text] Under basic conditions, 2'-aldehydo (acetonyl) 2-O-Ms(Ts)-alpha-C-glycosides undergo an intramolecular S(N)2 reaction to form 1,2-cyclopropanated sugars, which react with nucleophiles (alcohols, thiols, and azide) at the anomeric carbon to give 2-C-branched glycosides. By way of contrast, the 1,2-cyclopropanes derived from 2'-ketones only react with thiols to give 2-C-branched thioglycosides.

Catalysis↗
PubMed2002

Effect of configuration of muramyl dipeptide glycoside bond and structure of glycoside aglycon on their capacity to stimulate production of interleukin-1 and tumor necrosis factor by macrophages.

Effects of 11 original glycoside derivatives of muramyl dipeptide on the production of interleukin-1 and tumor necrosis factor by mouse peritoneal macrophages were studied. The relationship between macrophage activation evaluated by induction of these cytokines and configuration of glycoside bond and aglycon structure of MDP was revealed.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1977

Immunization with dextransucrases, levansucrases, and glycosidic hydrolases from oral streptococci. II. Immunization with glucosyltransferases, fructosyltransferases, and glycosidic hydrolases from oral streptococci in monkeys.

The feasibility of immunizing monkeys with enzymes from oral streptococci in an attempt to reduce dental caries was investigated. Forty rhesus monkeys, Macaca mulatta, were used. Cariogenic streptococci, S mutans, were implanted into all the monkeys' mouths. There was no pathological effect resulting from immunization. Of the 40 animals, 30 retained the implanted flora throughout the experiment; the remaining 10 were reimplanted until the streptococci remained. In six months, gross carious lesions were evident with plaque. Inhibitiors present in the monkey sera after immunization inhibited glucosyltransferase, fructosyltransferase, and neuraminidase activities. It was presumed the inhibitors were antibodies. There was a reduction of 68.6% in the total carious lesions in the animals immunized intraorally with glucosyltransferase, 62.4% reduction in those injected with fructosyltransferase, and 57.4% reduction in total lesions in those immunized with glycosidic hydrolases after 19 months, as compared to the control group. There were no gross lesions apparent in the group immunized with glycosidic hydrolases. It appears that immunization with enzymes significantly reduces carries and is feasible in a primate model.

Animals↗
PubMed1992

Galloyl-oxypaeoniflorin, suffruticosides A, B, C, and D, five new antioxidative glycosides, and suffruticoside E, A paeonol glycoside, from Chinese moutan cortex.

Five new antioxidative glycosides named galloyl-oxypaeoniflorin, suffruticosides A, B, C, and D, and a new paeonol glycoside named suffruticoside E have been isolated from Chinese Moutan Cortex, the root cortex of Paeonia suffruticosa ANDREWS, together with antioxidative galloyl-paeoniflorin. Their structures were elucidated on the basis of chemical and physicochemical evidences. Galloyl-oxypaeoniflorin, galloyl-paeoniflorin, suffruticosides A, B, C, and D showed more potent radical scavenging and antioxidative effects than alpha-tocopherol.

Antioxidants↗
PubMed1993

Resin glycosides. XIX. Woodrosins I and II, ether-insoluble resin glycosides from the stems of Ipomoea tuberosa.

Two new ether-insoluble resin glycosides named woodrosins I and II were isolated from the stems of Ipomoea tuberosa L., and their structures were determined on the basis of chemical and spectral data. Contrary to anticipation, they had an intramolecular cyclic ester structure similar to that of ether-soluble resin glycosides (Mayer's jalapin) hitherto isolated. It is proposed to use the terms, "jalapin" and "convolvulin," not according to the solubility in ether (Mayer's classification), but according to the structure, i.e., intramolecular esters and others, respectively.

Carbohydrate Sequence↗
PubMed1997

Medicinal foodstuffs. X. Structures of new triterpene glycosides, gymnemosides-c, -d, -e, and -f, from the leaves of Gymnema sylvestre R. Br.: influence of gymnema glycosides on glucose uptake in rat small intestinal fragments.

Following the characterization of gymnemosides-a and -b, new triterpene glycosides, gymnemosides-c, -d, -e, and -f, were isolated from the leaves of Gymnema (G.) sylvestre R. BR. Their chemical structures were elucidated on the basis of chemical and physicochemical evidence as follows: 21-O-benzoyl-28-O-acetylgymnemagenin 3-O-beta-D-glucopyranosiduronic acid (gymnemoside-c), 23-O-[beta-D-xylopyranosyl (1-->6)-beta-D-glucopyranosyl (1-->6)-beta-D-glucopyranosyl] gymnestrogenin (gymnemoside-d), 23-O-[beta-D-xylopyranosyl (1-->6)-beta-D-glucopyranosyl (1-->6)-beta-D- glucopyranosyl]-28-O-[beta-D-glucopyranosyl (1-->6)-beta-D-glucopyranosyl] 23-hydroxylongispinogenin (gymnemoside-e), 23-O-[beta-D-xylopyranosyl (1-->6)-beta-D-glucopyranosyl (1-->6)-beta-D-glucopyranosyl]-28-O-[beta-O-glucopyranosyl (1-->6)-beta-D-glucopyranosyl] 3 beta,16 beta,23,28-tetrahydroxyolean-18-ene (gymnemoside-f). The inhibitory effects of gymnemosides-c, -d, -e, and -f and principal triterpene glycosides from G. sylvestre on glucose uptake in rat small intestinal fragments were examined, and gymnemic acids II, III, and IV, gymnemasaponin V, and gymnemoside-f were found to exhibit the inhibitory activity.

Animals↗
PubMed2000

Medicinal foodstuffs. XIX. Absolute stereostructures of canavalioside, a new Ent-kaurane-type diterpene glycoside, and gladiatosides A1, A2, A3, B1, B2, B3, C1, and C2, new acylated flavonol glycosides, from sword bean, the seeds of Canavalia gladiata.

A new ent-kaurane-type glycoside, canavalioside, and eight new acylated flavonol glycosides, gladiatosides A1, A2, A3, B1, B2, B3, C1, and C2, were isolated from the seed of Canavalia gladiata together with robinin, kaempferol 3-O-beta-D-galactopyranosyl-7-O-alpha-L-rhamnopyranoside, and kaikasaponin III. The absolute stereostructures of canavalioside and gladiatosides A1, A2, B1, B2, B3, C1, and C2 were elucidated on the basis of chemical and physicochemical evidence.

Chemical Phenomena↗
PubMed2004

A new lignan glycoside and phenylethanoid glycosides from Strobilanthes cusia BREMEK.

The root of Strobilanthes cusia BREMEK. (Acanthaceae), popularly known as Da-Ching-Yeh, has been commonly used in traditional Chinese medicine. It is used to treat influenza, epidemic cerebrospinal meningitis, encephalitis B, viral pneumonia, mumps, and severe acute respiratory syndrome (SARS). In this study, we found a new lignan glycoside (6) and two new phenylethanoid glycosides (7, 8) together with five known compounds as chemical constituents of Strobilanthes cusia root. Some samples were examined for anti-herpes simplex virus type-1 (HSV-1) activity. Among the tested samples, lupeol showed anti-HSV-1 activity (EC(50): 11.7 microM) and showed 100% inhibition of virus plaque formation at 58.7 microM.

Acanthaceae↗
PubMed2000

Epoxyalkyl glycosides of D-xylose and xylo-oligosaccharides are active-site markers of xylanases from glycoside hydrolase family 11, not from family 10.

A series of omega-epoxyalkyl glycosides of D-xylopyranose, xylobiose and xylotriose were tested as potential active-site-directed inhibitors of xylanases from glycoside hydrolase families10 and 11. Whereas family-10 enzymes (Thermoascus aurantiacus Xyn and Clostridium thermocellum Xyn Z) are resistant toelectrophilic attack of active-site carboxyl residues, glycosidehydrolases of family 11 (Thermomyces lanuginosus Xyn and Trichoderma reesei Xyn II) are irreversibly inhibited. Theapparent inactivation and association constants (k(i), 1/K(i)) are one order of magnitude higher for thexylobiose and xylotriose derivatives. The effects of the aglycone chainlength can clearly be described. Xylobiose and n-alkyl beta-D-xylopyranosides are competitive ligands and provide protectionagainst inactivation. MS measurements showed 1:1 stoichiometries inmost labelling experiments. Electrospray ionization MS/MS analysisrevealed the nucleophile Glu(86) as the modified residue inthe T. lanuginosus xylanase when 2,3-epoxypropyl beta-D-xylopyranoside was used, whereas the acid/base catalyst Glu(178) was modified by the 3,4-epoxybutyl derivative. The active-site residues Glu(86) and Glu(177) in T. reesei Xyn II are similarly modified, confirming earlier X-raycrystallographic data [Havukainen, Törrönen, Laitinen and Rouvinen (1996)Biochemistry 35, 9617-9624]. The inability of the omega-epoxyalkyl xylo(oligo)saccharide derivatives to inactivate family-10enzymes is discussed in terms of different ligand-subsiteinteractions.

Alkylation↗
PubMed1989

[The biotransformation of leiocarposide and salicin phenol glycosides--examples for special consideration of the absorption and metabolism of glycosidic compounds].

After parenteral administration of leiocarposide (1, 3-beta-D-glucopyranosyloxy-2-methoxy-6-hydroxybenzoic acid-2'-beta-D-glucopyranosyloxybenzylester) and salicin to the rat the glycosides were mostly excreted unchanged in urine. In contrast to the oral administration (see [1]) only small amounts of metabolites [1: 0.2% of the dose as leiocarpic acid and 0.1% salicylic acid; 2: 0.05% 5] were observed. By in vitro experiments could be shown, that the hydrolysis of ester and glycosidic bonds from 1 to 3 and saligenin and from 2 to 4 took place microbially mostly in the cecum and colon of the rats. The reactions are also visible in the homogenate of kidney. Präparations of liver, lung and serum showed no activity. 4 in the homogenates of liver, kidney and lung, in the gut-wall and the serum was oxidized to 5. The further product of oxidation of 5, gentisic acid, arise only in liver homogenate.

Animals↗
PubMed1976

[Serum glycoside level in old age. Problems of course control in glycoside therapy].

Many intoxications--up to 20%--and the often described "digitalis-incompatibility of old age" require a strict indication for this long term therapy and a critical discussion to conceptions like "old age-heart" and "insufficiency of old age-heart". The factors of uncertainty for efficient therapy -- unknown rates of resorption and elimination, mistakes in dosage by patients and interaction with other medicaments on account of the multimorbidity of old age -- demand a better control than only clinical observation and electrocardiography. In 25 patients the serum glycoside concentration was evaluated during several weeks at constant dose by radioimmunoassay and analyzed. Digoxin-assay has to be available as an "emergency-measure", since the early diagnosis of digitalis intoxication in old patients is often very difficult because of the ambiguous clinical picture. 63 patients of different age with normal function of the kidneys (endogenous creatinin-clearance, nephrography with iodine-131-hippuran) were treated with 0,75 mg digoxin/die orally and the serum glycoside concentration was evaluated after 8, 24 and 48 hours by radioimmunoassay; we only found a dependence on weight, but not on the age of our patients. In old age, digoxin is metabolized in the same way as in young age, but because of frequent kidney diseases, kidney function should be assessed carefully before long term digoxin therapy.

Age Factors↗
PubMed1984

2-Bromoethyl glycosides in glycoside synthesis: preparation of glycoproteins containing alpha-L-Fuc-(1----2)-D-Gal and beta-D-Gal-(1----4)-D-GlcNAc.

The applicability of 2-bromoethyl glycosides in carbohydrate synthesis is demonstrated by the synthesis of glycosides of alpha-L-Fuc-(1----2)-D-Gal and beta-D-Gal-(1----4)-D-GlcNAc. The bromoethyl aglycon was transformed into the methoxycarbonylethylthioethyl spacer, which allowed coupling of the sugars to proteins (BSA and KLH).

Acetylglucosamine↗
PubMed1996

Vinyl Glycosides in Oligosaccharide Synthesis. 2. The Use of Allyl and Vinyl Glycosides in Oligosaccharide Synthesis.

A novel latent-active glycosylation strategy has been described that relies on the isomerization of substituted allyl glycosides to give the corresponding vinyl glycosides, which can subsequently be used in Lewis acid-mediated glycosylations. The isomerization reaction was performed by a rhodium catalyst obtained by treating tris(triphenylphosphine)rhodium(I) chloride with n-butyllithium. This catalyst has many advantageous properties over the use of conventional Wilkinson's catalyst. The glycosylation reactions gave high yields for both primary and secondary sugar alcohols, and the anomeric selectivity could be controlled by the constitution of the glycosyl donor and reaction conditions. The new isomerization and glycosylation approach enables complex oligosaccharides of biological importance to be prepared in a highly convergent manner.

Journal Article↗