Antioxidant and immunoregulatory activity of different polysaccharide fractions from tuber of Ophiopogon japonicus

► Five sulfated polysaccharides were prepared from the tuber of Ophiopogon japonicus. ► Polysaccharide with least of sulfate and hexuronic acid had lower antioxidant ability. ► The other four polysaccharides had stronger antioxidant ability. ► Five polysaccharides remarkably activate macrophage and promote cytokine release. ► The antioxidant and immune-enhancing activities depend on the content of hexuronic acid and sulfate.