Immunoregulation and antioxidant activities of a novel acidic polysaccharide from Radix Paeoniae Alba

Radix Paeoniae Alba is widely used in Chinese traditional medicine to treat various diseases such as gastrointestinal disorders, immunomodulatory, cancer, and other diseases. In this paper, a novel acidic polysaccharide RPAPS purified from Radix Paeoniae Alba was evaluated for its structural features and potential of immunomodulatory and antioxidant activities. RPAPS (molecular weight: 1.0× 10 5  Da) was mainly composed of α-(1 → 4)-Glc p , α-Ara p , α-Gal p , α-Rha p , β-D-Glc p , α-(1 → 6)-linked Glc p and GalA. Immunological tests indicated that RPAPS could improve RAW264.7 phagocytic activity and LPS-induced splenocyte proliferation. For antioxidant activities, RPAPS showed reducing power and DPPH scavenging activity in dose dependent. Moreover, RPAPS could significantly protect the PC12 cells from H 2 O 2 damage. These data implied polysaccharides RPAPS had the potential to be novel natural antioxidative and immunopotentiating agents for using in functional foods or medicine.