Antioxidant activities of sulfated pumpkin polysaccharides.

Pumpkin polysaccharide was extracted by hot water extraction method. It was modified with chlorosulfonic acid-pyridine to obtain sulfated pumpkin polysaccharides (SP1, SP2) with different degrees of substitution, which was 0.35 and 0.65, respectively. The total sugar contents of pumpkin polysaccharide and its sulfated derivatives were determined by phenol‑sulfuric acid method, the ability of scavenging hydroxyl radicals and superoxide anions as well as the ability of reducing were determined. The results showed the scavenging effect of sulfated derivatives on hydroxyl radicals was not different after 0.8 mg/mL and was lower than that of pumpkin polysaccharides. The sulfated pumpkin polysaccharides with different degrees of substitution had better scavenging effects on superoxide anions than pumpkin polysaccharide, but the reducing ability was lower than that of pumpkin polysaccharide.