Exploiting diol reactivity for the access to unprecedented low molecular weight curdlan sulfate polysaccharides

Giulia Vessella; Fabiana Esposito; Serena Traboni; Celeste Di Meo; Alfonso Iadonisi; Chiara Schiraldi; Emiliano Bedini

doi:10.1016/j.carbpol.2021.118324

Exploiting diol reactivity for the access to unprecedented low molecular weight curdlan sulfate polysaccharides

Carbohydr Polym. 2021 Oct 1:269:118324. doi: 10.1016/j.carbpol.2021.118324. Epub 2021 Jun 10.

Authors

Giulia Vessella¹, Fabiana Esposito¹, Serena Traboni¹, Celeste Di Meo², Alfonso Iadonisi¹, Chiara Schiraldi², Emiliano Bedini³

Affiliations

¹ Department of Chemical Sciences, University of Naples Federico II, Complesso Universitario Monte S.Angelo, via Cintia 4, I-80126 Napoli, Italy.
² Department of Experimental Medicine, Section of Biotechnology, University of Campania "Luigi Vanvitelli", via de Crecchio 7, I-80138 Napoli, Italy.
³ Department of Chemical Sciences, University of Naples Federico II, Complesso Universitario Monte S.Angelo, via Cintia 4, I-80126 Napoli, Italy. Electronic address: ebedini@unina.it.

PMID: 34294336
DOI: 10.1016/j.carbpol.2021.118324

Abstract

Curdlan is a bacterial sourced polysaccharide, consisting of a linear backbone of β-1 → 3-linked glucose (Glc) units. The high interest in pharmaceutical applications of curdlan and derivatives thereof is fueling the study of multi-step sequences for regioselective modifications of its structure. Here we have developed semi-synthetic sequences based on a regioselective protection-sulfation-deprotection approach, allowing the access to some, new, low molecular weight curdlan polysaccharide derivatives with unprecedented sulfation patterns. Three different semi-synthetic schemes were investigated, all relying upon the installation of a cyclic benzylidene protecting group on Glc O-4,6-diols, followed by either direct sulfation and deprotection, or some additional steps - including a hydrolytic or oxidative cleavage of the benzylidene rings - prior to sulfation and deprotection. The six obtained polysaccharides were subjected to a detailed structural characterization by 2D-NMR analysis, revealing that some of them showed the majority of Glc units along the polymeric backbone decorated by unprecedented sulfation motifs.

Keywords: Benzylidene; Diol reactivity; Low molecular weight curdlan; Protecting group; Regioselective sulfation.