Anti-tumor and immunomodulating activities of a polysaccharide from the root of Sanguisorba officinalis L.

► A polysaccharide (SOWP) is purified from the roots of Sanguisorba officinalis L. ► SOWP significantly inhibits the growth of mouse transplantable tumor. ► SOWP remarkably increases the spleen index and promote splenocytes proliferation, SOWP effectively activate macrophage phagocytosis. ► SOWP increases serum IL-2, TNF-α and IFN-γ levels in tumor-bearing mice.