Preparation and antiherpetic activities of chemically modified polysaccharides from Polygonatum cyrtonema Hua

The chemically modified polysaccharides, including sulfated, phosphorylated, carboxymethylated, acetylated and sulfonylated derivatives, were prepared from a neutral polysaccharide (PD) extracted from Polygonatum cyrtonema Hua. These compounds were characterized by FT-IR, 1H NMR and 13C NMR spectroscopy. Antiherpetic activities of natural and modified P. cyrtonema polysaccharide against herpes simplex virus (HSV) induced by cyclophosphamide (CP) were then evaluated on vero cells using cytopathic effect (CPE) inhibition assay. The phorphorylated derivative (P-PD) and sulfated derivative (S-PD), exhibited significant inhibitory activity against HSV in comparison with the native ones, especially, P-PD presented better antiviral potency. In addition, the sulfonylated derivative (Ts-PD) was found to be as effective as PD, and the acetylated derivative (Ac-PD) to be slightly less antiviral effective, whereas carboxymethylated derivative (C-PD) was shown to be almost inactive. The results indicated that the types of function groups appeared to be very important for the antiherpetic activity of polysaccharides.