Search results for "Arid"
showing 10 items of 1382 documents
3′-Demethyldihydromaldoxin and dihydromaldoxin, two anti-inflammtory diaryl ethers from a Steganospora species
2012
CXCL10 (IP-10) is a highly inducible chemoattractant, which contributes to the recruitment of inflammatory cells such as macrophages and T-lymphocytes and thereby has important roles in chronic inflammatory conditions. In a search for new inhibitors of CXCL10 expression in MonoMac6 (MM6) cells, the new diaryl ether 3'-demethyldihydromaldoxin (1) along with the known compound dihydromaldoxin (2), were isolated from fermentations of a Steganospora species. The structures of the compounds were elucidated by a combination of one- and two-dimensional NMR spectroscopy and mass spectrometry. Compounds (1) and (2) inhibited lipopolysaccharide (LPS)/interferon-γ (IFN-γ)-induced CXCL10 promoter activ…
Synthesis, Characterization, and Saccharide Binding Studies of Bile Acid − Porphyrin Conjugates
2007
Synthesis and characterization of bile acid-porphyrin conjugates (BAPs) are reported. Binding of saccharides with BAPs in aqueous methanol was studied by monitoring changes in the visible absorption spectral of the porphyrin-moieties. Although these studies clearly showed absorbance changes, suggesting quite high if non-selective binding, the mass spectral studies do not unambiguously support these results.
Structural analysis of the O-specific polysaccharide isolated from Plesiomonas shigelloides O51 lipopolysaccharide.
2009
Plesiomonasshigelloides strain CNCTC 110/92 (O51) was identified as a new example of plesiomonads synthesising lipopolysaccharides (LPSs) that show preference for a non-aqueous surrounding during phenol/water extraction. Chemical analyses combined with (1)H and (13)C NMR spectroscopy, MALDI-TOF and ESI mass spectrometry showed that the repeating units of the O-specific polysaccharides isolated from phenol and water phase LPSs of P. shigelloides O51 have the same structure: -->4)-beta-D-GlcpNAc3NRA-(1-->4)-alpha-L-FucpAm3OAc-(1-->3)-alpha-D-QuipNAc-(1-->, containing the rare sugar constituent 2,3-diamino-2,3-dideoxyglucuronic acid (GlcpNAc3NRA), and substituents such as D-3-hydroxybutyric ac…
Chemoenzymatic Synthesis of Functional Sialyl LewisX Mimetics with a Heteroaromatic Core
2014
Functional mimetics of the sialyl Lewis(X) tetrasaccharide were prepared by the enzymatic sialylation of a 1,3-diglycosylated indole and a glycosyl azide, which was subsequently transformed into a 1,4-diglycosylated 1,2,3-triazole, by using the trans-sialidase of Trypanosoma cruzi. These compounds inhibited the binding of E-, L-, and P-selectin-coated nanoparticles to polyacrylamide-bound sialyl-Lewis(X) -containing neighboring sulfated tyrosine residues (sTyr/sLe(X) -PAA) at low or sub-millimolar concentrations. Except for E-selectin, the mimetics showed higher activities than the natural tetrasaccharide.
Structural analysis of the lipid A isolated from Hafnia alvei 32 and PCM 1192 lipopolysaccharides[S]
2010
Hafnia alvei, a Gram-negative bacterium, is an opportunistic pathogen associated with mixed hospital infections, bacteremia, septicemia, and respiratory diseases. The majority of clinical symptoms of diseases caused by this bacterium have a lipopolysaccharide (LPS, endotoxin)-related origin. The lipid A structure affects the biological activity of endotoxins predominantly. Thus, the structure of H. alvei lipid A was analyzed for the first time. The major form, asymmetrically hexa-acylated lipid A built of beta-D-GlcpN4P-(1-->6)-alpha-D-GlcpN1P substituted with (R)-14:0(3-OH) at N-2 and O-3, 14:0(3-(R)-O-12:0) at N-2', and 14:0(3-(R)-O-14:0) at O-3', was identified by ESI-MS(n) and MALDI-tim…
Selective killing of human monocytes and cytokine release provoked by sphingomyelinase (beta-toxin) of Staphylococcus aureus.
1996
The best-known activity of Staphylococcus aureus sphingomyelinase C, alias beta-toxin, is as a hemolysin that provokes hot-cold lysis of erythrocytes which contain substantial amounts of sphingomyelin in the plasma membrane. Sheep erythrocytes are most susceptible, and we found that one hemolytic unit, representing the toxin concentration that elicits 50% hemolysis of 2.5 X 10(8) erythrocytes per ml, corresponds to 0.05 enzyme units or to approximately 0.25 microg of sphingomyelinase per ml. The cytotoxic action of beta-toxin on nucleated cells has not been described in any detail before, and the present investigation was undertaken to fill this information gap. We now identify beta-toxin a…
Acylated Preatroxigenin Glycosides from Atroxima congolana
2003
Six new acylated bisdesmosidic preatroxigenin saponins named atroximasaponins E1, E2 (1, 2), F1, F2 (3, 4), and G1, G2 (5, 6) were isolated as three inseparable mixtures of the trans- and cis-p-methoxycinnamoyl derivatives, from the roots of Atroxima congolana. Their structures were established through extensive NMR spectroscopic analysis as 3-O-beta-D-glucopyranosylpreatroxigenin-28-O-beta-D-xylopyranosyl-(1--4)-alpha-L-rhamnopyranosyl-(1--2)-[beta-D-glucopyranosyl-(1--3)]-[4-O-trans-p-methoxycinnamoyl]-beta-D-fucopyranoside (atroximasaponin E1, 1), and its cis-isomer, atroximasaponin E2 (2), 3-O-beta-D-glucopyranosylpreatroxigenin-28-O-beta-D-xylopyranosyl-(1--4)-alpha-L-rhamnopyranosyl-(…
Three New Triterpene Saponins from Two Species of Carpolobia
2002
Three new acetylated triterpene saponins 1-3 were isolated from the roots of Carpolobia alba and C. lutea. Their structures were established mainly by 2D NMR techniques as 3-O-beta-D-glucopyranosylpresenegenin-28-O-beta-D-galactopyranosyl-(1-->4)-[beta-D-xylopyranosyl-(1-->3)]-beta-D-xylopyranosyl-(1-->4)-alpha-L-rhamnopyranosyl-(1-->2)-(3,4-di-O-acetyl)-beta-D-fucopyranosyl ester, 3-O-beta-D-glucopyranosylpresenegenin-28-O-beta-D-galactopyranosyl-(1-->4)-[alpha-L-arabinopyranosyl-(1-->3)]-beta-D-xylopyranosyl-(1-->4)-alpha-L-rhamnopyranosyl-(1-->2)-(3,4-di-O-acetyl)-beta-D-fucopyranosyl ester, and 3-O-beta-D-glucopyranosylpresenegenin-28-O-beta-D-xylopyranosyl-(1-->4)-[beta-D-apiofuranosyl…
Glandulosides A-D, triterpene saponins from Acanthophyllum glandulosum.
2004
Four novel triterpenoid saponins, glandulosides A (1), B (2), C (3), and D (4), together with two known saponins (5 and 6) have been isolated from the roots of Acanthophyllum glandulosum. Their structures were elucidated using a combination of homo- and heteronuclear 2D NMR techniques (COSY, TOCSY, NOESY, HSQC, and HMBC) and by FABMS. The new compounds were characterized as 23-O-beta-D-galactopyranosylgypsogenic acid-28-O-beta-D-glucopyranosyl-(1-->3)-[beta-d-galactopyranosyl-(1-->6)]-beta-D-galactopyranoside (1), 3-O-beta-D-galactopyranosyl-(1-->2)-[beta-D-xylopyranosyl-(1-->3)]-beta-D-glucuronopyranosylgypsogenin-28-O-beta-D-xylopyranosyl-(1-->3)-beta-D-xylopyranosyl-(1-->4)-alpha-l-rhamn…
Steroidal saponins from Chlorophytum orchidastrum.
2009
Six new spirostane-type saponins (1−6), named orchidastrosides A−F, and chloromaloside D were isolated from an ethanol extract of the roots of Chlorophytum orchidastrum. The saponins have neotigogenin or neogitogenin as the aglycon and oligosaccharidic chains possessing seven to nine sugar units. Their structures were elucidated mainly by 2D NMR spectroscopic analyses (COSY, TOCSY, NOESY, HSQC, and HMBC) and FABMS and HRESIMS. Compounds 1−6 were tested for cytotoxicity against two human colon cancer cell lines, HCT 116 and HT-29.