Search results for "GAL"
showing 10 items of 9260 documents
Bioactive saponins with cancer related and immunomodulatory activity: Recent developments
2005
Abstract Saponins are natural glycosides of steroid or triterpene which exhibited many different biological and pharmacological actions: e.g. immunomodulatory, antitumor, antiinflammatory, molluscicidal, antiviral, antifungal, hypoglycemic, hypocholesterolemic, to mention just a few. The aim of this summarize recent advances on the bioactivity of saponins related to cancer and immune system, which has attracted a great attention during the last five years
Water-soluble polysaccharides from Opuntia stricta Haw. fruit peels: Recovery, identification and evaluation of their antioxidant activities
2015
Abstract Opuntia stricta Haw. is considered as one of the most common cactus plant growing in Tunisia. Extracting valuable compounds from its fruit peel, considered as by-product, is drawing more and more attention, making it on the verge of commercialization. Water-soluble polysaccharides were extracted from Opuntia stricta Haw. peels, and their chemical composition assessed using thin layer chromatography. The antioxidant activities of the extracted polysaccharides were assessed using 2,2-diphenyl-1-picrylhydrazyl free radical scavenging activity, total antioxidant activity and reducing power capacity. The extraction yield of water-soluble polysaccharides was 7.53±0.86%. The chemical comp…
ERA-experiment “space biochemistry”
1995
Abstract The general goal of the experiment was to study the response of anhydrobiotic (metabolically dormant) microorganisms (spores of Bacillus subtilis, cells of Deinococcus radiodurans, conidia of Aspergillus species) and cellular constituents (plasmid DNA, proteins, purple membranes, amino acids, urea) to the extremely dehydrating conditions of open space, in some cases in combination with irradiation by solar UV-light. Methods of investigation included viability tests, analysis of DNA damages (strand breaks, DNA-protein cross-links) and analysis of chemical effects by spectroscopic, electrophoretic and chromatographic methods. The decrease in viability of the microorganisms was as exp…
Synthesis of cyanoacetic acid by carbon dioxide and electrogenerated acetonitrile anion in undivided cells equipped with sacrificial anodes
2008
The electrochemical synthesis of cyanoacetic acid was performed by cathodic reduction of tetraalkylammonium salts (R4NX) in acetonitrile in undivided cells equipped with sacrificial anodes with concomitant or subsequent addition of carbon dioxide. These syntheses avoid the use of dangerous reagents, yield cyanoacetic acid in moderate faradic yields and confirm that the cathodic reduction of tetraalkylammonium salts in the presence of acetonitrile leads to the formation of the anion CNCH2-.
Carbamate Linker Strategy in Solid-Phase Synthesis of Amino-Functionalized Glycoconjugates for Attachment to Solid Surfaces and Investigation of Prot…
2009
Amino-functionalized serine-based galactose and glucose neoglycolipids were prepared by solid-phase synthesis using a carbamate strategy for anchoring amino functionalities to a (2-fluoro-4-hydroxy ...
A strategy for chromatographic and structural analysis of monosaccharide species from glycoproteins.
1996
A general strategy for the chromatographic and structural analysis of the monosaccharide species fucose (Fuc), N-acetylgalactosamine (GalNAc), N-acetylglucosamine (GlcNAc), galactose (Gal), glucose (Glc), mannose (Man), N-acetylneuraminic acid (NANA) present in glycoproteins is described. Qualitative and quantitative aspects for the separation of these glycoprotein monosaccharides (monosaccharide species) using ligand-exchange chromatography (LEC) and high pH anion-exchange chromatography (HPAEC) in combination with pulsed-amperometric detection (PAD), refractive index (RI) and ultraviolet (UV) monitoring are discussed in detail. The conditions for the acidic hydrolysis of glycoproteins and…
Inhibition of cyclodextrins on α-galactosidase.
2017
This work successfully investigated the effects of different influential factors and hydrophobic cavities of cyclodextrins (CDs) on α-galactosidase (α-Gal) by detecting α-Gal activity. The highest inhibitory concentration of three kinds of CDs (α-, β-, and γ-CD) on α-Gal was 10mM. Moreover, the highest inhibition of α-Gal was obtained under the following conditions: reaction time of 90min, temperature of 30°C, and pH 6.0. Compared with other CDs, β-CD showed more ability to interact with α-Gal due to its appropriate cavity geometric dimensions. From circular dichroism and nuclear magnetic resonance it was observed that β-CD changed the secondary structure of α-Gal and formed a hydrogen bond…
Role of hexagonal structure-forming lipids in diadinoxanthin and violaxanthin solubilization and de-epoxidation
2005
In this study, we have examined the influence of different lipids on the solubility of the xanthophyll cycle pigments diadinoxanthin (Ddx) and violaxanthin (Vx) and on the efficiency of Ddx and Vx de-epoxidation by the enzymes Vx de-epoxidase (VDE) from wheat and Ddx de-epoxidase (DDE) from the diatom Cyclotella meneghiniana, respectively. Our results show that the lipids MGDG and PE are able to solubilize both xanthophyll cycle pigments in an aqueous medium. Substrate solubilization is essential for de-epoxidase activity, because in the absence of MGDG or PE Ddx and Vx are present in an aggregated form, with limited accessibility for DDE and VDE. Our results also show that the hexagonal st…
Synthesis of Trisaccharides by Hetero-Diels–Alder Welding of Two Monosaccharide Units
2012
A new strategy for the synthesis of di- and trisaccharides based on the de novo synthesis of the linking saccharide unit is presented. In this strategy, functionalized monosaccharide building blocks already incorporating the glycosidic linkages are welded together using a metal-catalyzed hetero-Diels–Alder (HDA) reaction to generate a new monosaccharide unit between them. The highest yields and selectivities in the HDA reaction were obtained by using chiral Schiff base chromium complexes. Disaccharide products were accessible by reaction of Danishefsky's diene with acetyl- and benzyl-protected galactoside aldehydes. For the synthesis of trisaccharide products, acetyl-protected glucose or ga…
Total Synthesis of a Partial Structure from Arabinogalactan and Its Application for Allergy Prevention
2020
Abstract Arabinogalactan, a microheterogeneous polysaccharide occurring in plants, is known for its allergy‐protective activity, which could potentially be used for preventive allergy treatment. New treatment options are highly desirable, especially in a preventive manner, due to the constant rise of atopic diseases worldwide. The structural origin of the allergy‐protective activity of arabinogalactan is, however, still unclear and isolation of the polysaccharide is not feasible for pharmaceutical applications due to a variation of the activity of the natural product and contaminations with endotoxins. Therefore, a pentasaccharide partial structure was selected for total synthesis and subse…