A polysaccharide isolated from Sphallerocarpus gracilis protects PC12 cells against hydrogen peroxide-induced injury

Sphallerocarpus gracilis is a medicinal and edible plant in China with high nutritional value. We examined the structure and bioactivity of a new polysaccharide fraction purified from S. gracilis named SGP-1. This polysaccharide possessed an average molecular weight of 4.916 × 10⁵ and was primarily composed of arabinose, mannose and glucose in a molar ratio of 1.08:94.54:4.38. Atomic force microscopy indicated that SGP-1 adopts a sphere-like chain conformation. Bioactivity tests showed that SGP-1 significantly protected PC12 cells from oxidative injury caused by H₂O₂ and enhanced superoxide dismutase and glutathione peroxidase activities. Moreover, SGP-1 reduced PC12 apoptosis by inhibiting Caspase-3 and Caspase-9 activities. These results provide a scientific basis for the further use of SGP-1 as a novel functional component in the treatment of oxidative damage-derived diseases.