Separation of O- and C-allyl glycoside anomeric mixtures by capillary electrophoresis and high-performance liquid chromatography

Rapid and reliable methods for the analysis of O- and C-allyl galactopyranosides and glucopyranosides are presented, based on capillary zone electrophoresis (CZE) and micellar electrokinetic capillary chromatography (MEKC). In MEKC, the formation of chromophoric and charged complexes between the saccharides and borate as well as the hydrophobic interactions with micelles jointly contributed to the selective separation and sensitive detection of all the investigated anomeric couples. Some non-purified synthesis mixtures of C-allyl glycosides were successfully characterised without pre-treatment. MEKC buffer conditions for which glycosides separation was successfully achieved were then exported and applied to reverse-phase liquid chromatography (RP-HPLC), for the quantitative isolation of each allyl glycoside anomer. Identification of the obtained anomeric products was performed by electrospray mass spectrometry and 13C NMR spectroscopy. Glycoside\u2013solvent interactions driving the selective anomeric separation were shortly addressed and discussed on the basis of sugar derivatives structural differences

Polyol Synthesis of Silver Nanoparticles: Mechanism of Reduction by Alditol Bearing Polysaccharides

Alditol bearing chitosans have shown the ability to reduce silver ions in mild conditions and without addition of exogenous reducing agents. The ion reduction induces the formation of a lactone moiety on the polysaccharide (Fetizon reaction) without causing C-C bond cleavage on the polyol. The close and multivalent arrangement of the endogenous reducing agent (alditols) on the polysaccharide backbone resulted in the formation of silver nanoparticles (O < 10 nm), which induced a considerable SERS effect and led to hydrogel formation

Can the interaction between the antimicrobial peptide LL-37 and alginate be exploited for the formulation of new biomaterials with antimicrobial properties?

In this study, we took advantage of the strong interaction between the antimicrobialpeptideLL-37 and anionic polysaccharides, such as alginate, to design and evaluate a new biomaterial with putative antibacterial properties. To begin with, we have investigated the effect of different biocompatible polysaccharides on both the cytotoxicity and the antimicrobial activity of LL-37, a powerful endogenous antimicrobialpeptide of human origin, whose use in therapy has been hampered by its toxicity to host cells. Interactions of the peptide with polysaccharides were evaluated by circular dichroism analyses, which revealed a different capacity of the polymers to induce the active helical conformation in the peptide. Among the polysaccharides tested, sodium alginate was the only one that significantly reduced the toxicity of LL-37 toward mammalian cells. A sodium alginate/LL-37 preparation was then tested on four bacterial strains. The Gram-negative bacteria resulted susceptible to the mixture, while the growth of the Gram-positive ones was poorly affected and only at the highest peptide concentration tested. Following the positive results with Gram-negative species, the alginate/LL-37 binary system was used for the preparation of calcium alginate beads, which were tested for peptide release