The synthesis of a new unsaturated derivative of chondroitin sulfate with increased antioxidant properties

Chondroitin sulfate (CS) was regio-specifically modified to an unsaturated derivative (Delta CS) with a double bond in positions 4 and 5 of N-acetyl-D-galactosamine. The structure of Delta CS was elucidated in detail by two dimensional nuclear magnetic resonance, ultraviolet spectroscopy and mass spectrometry. The introduction of a nucleophilic -C=C- double bond into a polymer backbone had no influence on biocompatibility of CS, which was demonstrated by MTT live-dead assay and enzymatic degradation in vitro. On the other hand the chemical modification significantly enhanced the reactivity of Delta CS towards numerous oxidizing agents, which might be promising for a variety of biomedical and cosmetic applications.