No abstract

Chemical O-glycosylation of polysaccharides is an almost unexplored reaction. This is mainly due to the difficulties in derivatizing such complex biomacromolecules in a quantitative manner and with a fine control of the obtained structural parameters. In this work, chondroitin raw material from a microbial source was chemo- and regioselectively protected to give two polysaccharide intermediates, that acted in turn as glycosyl acceptors in fucosylation reactions. Further manipulations on the fucosylated polysaccharides, including multiple de-O-benzylation and sulfation, furnished for the first time nonanimal sourced fucosylated chondroitin sulfates (fCSs)-polysaccharides obtained so far exclusively from sea cucumbers (Echinoidea, Holothuroidea) and showing several very interesting biological activities. A semisynthetic fCS was characterized from a structural point of view by means of 2D-NMR techniques, and preliminarily assayed in an anticoagulant test.

Varying the nature of polymeric linkers modulates the aggregation response of glycosylated nanoparticles upon interaction with lectins.

Sulfated glycosaminoglycans (GAGs) are a family of complex polysaccharides ubiquitously distributed in extracellular matrices and at cell surfaces and playing key roles in a myriad of biological processes. Their structures are based on disaccharide building blocks, usually containing an amino sugar and an uronic acid, decorated with one or more sulfate groups. Many efforts to gain access to a large number of sulfated GAG polysaccharides with potential tailored biomedical applications, usually based on suitable chemical (and chemo-enzymatic) derivatization procedures that modified the native polysaccharide structures, have been reported in the last two decades. In this review we survey such reactions on the basis of (i) the sulfated GAG substrate [(fucosylated) chondroitin sulfate, dermatan sulfate, heparin, and heparan sulfate], and (ii) the sort of structural modification (sulfation pattern modification, oxidation, carboxy group derivatization, N- and O-acylation, reducing-end functionalization)