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 (ΔCS) with a double bond in positions 4 and 5 of N-acetyl-d-galactosamine. The structure of ΔCS was elucidated in detail by two dimensional nuclear magnetic resonance, ultraviolet spectroscopy and mass spectrometry. The introduction of a nucleophilic CC 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 ΔCS towards numerous oxidizing agents, which might be promising for a variety of biomedical and cosmetic applications.