Structure and heparanase inhibitory activity of a new glycosaminoglycan from the slug Limacus flavus

Abstract A new glycosaminoglycan (LF-GAG) was purified from the slug Limacus flavus . Its unique chemical structure and heparanase inhibitory activity were studied in this work. The native LF-GAG was composed of L-iduronic acid (L-IdoA) and N -acetyl-D-glucosamine (D-GlcNAc), with a Mw of 22,700 Da. To elucidate the precise structure and structure-activity relationship, its deacetylation-deaminative depolymerized product (dLF-GAG) was prepared, and from which four oligosaccharides were purified. Combining the NMR spectral analysis of LF-GAG and its derived oligosaccharides, the structure of LF-GAG was deduced to be -4)-L-IdoA 2R -(α1,4)-D-GlcNAc-(α1-, in which R was −OH (˜80%) or –OSO 3 − (˜20%). Bioactivity assays showed that LF-GAG could potently inhibit human heparanase (IC 50 , 0.10 μM). dLF-GAG and LF-3 were less potent but also active for heparanase inhibition. Structure-activity relationship analysis indicated that the chain length and sulfate substitution of LF-GAG are essential for its heparanase inhibitory activity.