Synthesis and evaluation of N-alkyl-β-d-glucosylamines on the growth of two wood fungi, Coriolus versicolor and Poria placenta

Hybrid emulsifier systems: Alkyl imidazolium lactoside surfactants derived from natural resources

A new series of hybrid surfactants comprising an imidazolium as a cation and a disaccharide as a non-ion were synthesized, and their aggregation behavior was also investigated. The synthetic approach used alkylation as an easily accessible route on an imidazole to attempt an economic production followed by coupling with bromoethyl lactoside to form lacto-imidazolium salts surfactants. The coupled surfactants were obtained in almost quantitative yield over several steps. The surfactant surface properties in aqueous media were investigated, including critical micelle concentration (CMC), Krafft temperature, and emulsion stability were studied. The CMC measurements of the alkyl imidazolium lactoside surfactants are significantly lower than normal imidazolium surfactants, while the emulsion investigations encourage the use of alkyl imidazolium lactoside surfactants owing to stabilized assemble behavior as good as APGs.

pH-Triggered release of an antifungal agent from polyglycidol-based nanoparticles against fuel fungus H. resinae

The goal of this investigation was the development of smart plurifunctional polymeric particles able to deliver a biocide following an acidic trigger due to the presence of microorganisms. Such particles were synthesized by Ring-Opening Metathesis Polymerization of an α-norbornenyl polyglycidol macromonomer functionalized with biocide through a pH-sensitive imine bond. H. resinae was selected as a target strain. In the first part, the pH sensitivity of the functionalized particles was studied. Then, the antifungal activity of both the biocide-functionalized macromonomer and the functionalized particles was evaluated. Incorporation of the particles in a commercial model coating was also tested, to verify that its original barrier properties were maintained.

Synthesis and evaluation of an N-[18F]fluorodeoxyglycosyl amino acid for PET imaging of tumor metabolism

INTRODUCTION

The limitations of [¹⁸F]fluorodeoxyglucose ([¹⁸F]FDG), including producing false-positive or -negative results, low image contrast in brain tumor diagnosis and poor differentiation of tumor and inflammatory, necessitate the development of new radiopharmaceuticals. In the present study, a novel [¹⁸F]fluoroglycoconjugate tracer, [¹⁸F]FDGly-NH-Phe, for tumor metabolism imaging was prepared and evaluated.

METHODS

[¹⁸F]FDGly-NH-Phe was prepared by condensing [¹⁸F]FDG with L-4-aminophenylalanine in an acidic condition, and purified with semi-preparative-high performance liquid chromatography (HPLC). The in vitro stability study was conducted in phosphate-buffered saline (PBS, pH 4.0-9.18) at room temperature (RT) and in fetal bovine serum (FBS) at 37 °C. The preliminary cellular uptake studies were performed using Hep-2 cell. The bio-distribution studies, PET/CT imaging and metabolism studies were performed and compared with [¹⁸F]FDG on ICR or BALB/c nude model mice.

RESULTS

[¹⁸F]FDGly-NH-Phe was derived from a direct condensation of [¹⁸F]FDG with L-4-aminophenylalanine with high stability in FBS and PBS (pH of 6.5-9.18). In vitro cell experiments showed that [¹⁸F]FDGly-NH-Phe uptake in Hep-2 cells was primarily transported through amino acid transporters including Na⁺-dependent A system, ASC system, and system B^0,+ system. The bio-distribution of [¹⁸F]FDGly-NH-Phe in normal ICR mice showed faster blood radioactivity clearance, and lower uptake in brain and heart than [¹⁸F]FDG. The performance of PET/CT imaging for [¹⁸F]FDGly-NH-Phe in the mice model manifested excellent tumor visualization, high tumor-to-background ratios, and low accumulation in inflammatory lesions. Metabolism studies for [¹⁸F]FDGly-NH-Phe indicated high in vivo stability in plasma and urine and decomposition into [¹⁸F]FDG in the tumor microenvironment.

CONCLUSION

The results demonstrated that [¹⁸F]FDGly-NH-Phe as a novel amino acid PET tracer showed the capability to differentiate tumor from inflammation, and the potentials for future clinical applications.

From glycals to aminosugars: a challenging test for new stereoselective aminohydroxylation and related methodologies

The most relevant methods to access 1-, 2-, 3-amino or 1,2-diaminosugars starting from unsaturated carbohydrates are concisely reviewed; the given examples illustrate the great challenges offered to several stereoselective strategies.

Alkyl-imidazolium glycosides: non-ionic-cationic hybrid surfactants from renewable resources

A series of surfactants combining carbohydrate and imidazolium head groups were prepared and investigated on their assembly behavior. The presence of the imidazolium group dominated the interactions of the surfactants, leading to high CMCs and large molecular surface areas, reflected in curved rather than lamellar surfactant assemblies. The carbohydrate, on the other hand, stabilized molecular assemblies slightly and reduced the surface tension of surfactant solutions considerably. A comparative emulsion study discourages the use of pure alkyl imidazolium glycosides owing to reduced assembly stabilities compared with APGs. However, the surfactants are believed to have potential as component in carbohydrate based surfactant mixtures.

Efficient synthesis of glycosylamines in solventless conditions promoted by mechanical milling

A mecanosynthesis of glycosylamines under solventless conditions was established. This environmentally friendly approach optimized with l-rhamnose, was investigated using a variety of amines and other carbohydrates.

Influence of the variation of the alkyl chain length of N-alkyl-β-D-glycosylamine derivatives on antifungal properties

Twelve new glucosidic and galactosidic derivatives of N-alkylaminosugars with different alkylamines from 6 to 18 carbons were synthesized and characterized by (1)H and (13)C NMR. Their antifungal activity against the food fungal pathogen Aspergillus niger was evaluated using the radial growth assay. The influence of the variation of the alkyl chain length of N-alkylaminosugars on the mycelium growth was then discussed. Inhibition by the different alkylamines is shown as a biostatic effect rather than a biocidal effect. It was observed that alkylamines keep their antifungal properties after a thermal treatment compatible with food packaging and processing.

Synthesis of D-glucosamine quaternary ammonium derivatives and evaluation of their antifungal activity together with aminodeoxyglucose derivatives against two wood fungi Coriolus versicolor and Poria placenta: structure-activity relationships

BACKGROUND

Structure-activity relationships are often reported in scientific studies. These may be employed in searching for new acceptable biocides to use against harmful microorganisms, because the biocides used hitherto encounter various problems, including lack of efficiency, high toxicity and persistence. Nowadays, scientists are trying to find new, environmentally acceptable biocides to replace these earlier biocides. Different compounds from renewable materials have been studied and have shown pronounced antifungal activity against wood fungi. These include aminopolysaccharide derivatives and different quaternary ammonium polymers. A biological study carried out with these products indicated a possible relationship between amino groups and differences in biological activity observed.

RESULTS

In this study, an amino group was successively fixed to different carbon atoms of glucose, and glucosamine was also modified by both N-alkylation and quaternisation. The impact of the amino group position on antifungal activity against two wood decay fungi was investigated. The amino group at the anomeric position showed the highest antifungal activity against both Coriolus versicolor Quel. and Poria placenta (Fr.) Cooke. Furthermore, the positive impact of both N-alkylation and quaternisation on the growth of both strains was demonstrated.

CONCLUSION

The anomeric position of the amino group and the N-alkylation and quaternisation of amino sugars considerably increase the antifungal activity of these compounds.