Sulfated modification can enhance antiglycation abilities of polysaccharides from Dendrobium huoshanense

Dendrobium huoshanense is an important edible-medicinal plant with high nutritional values and health functions. A homogenous polysaccharide (DHPD1) with molecular weight of 3.2 × 103 Da was extracted from D. huoshanense, which was mainly composed of glucose, arabinose, galactose, mannose and xylose. Chlorosulfonic acid-pyridine (CSA-Pyr) method was performed to modify the structure of DHPD1. In order to get a high degree of substitution (DS), sulfated modification conditions were optimized by response surface methodology. The maximum DS of 1.473 was obtained when the reaction condition was fixed at reaction temperature 60 °C, reaction time 160 min and volume ratio of Pyr to CSA 2:1. NMR spectra revealed that this sulfation occurred to C-2 and C-6 of glycosyl residues in DHPD1. After 28 days of incubation, the sulfated DHPD1 at 1.0 mg/mL showed the inhibitory ability of 58.5%, which increased by 16.2% and 52.5% than that of aminoguanidine and DHPD1 at the same dosage.