Antioxidant activities of five polysaccharides from Inonotus obliquus

Five polysaccharides (IOP1b, IOP2a, IOP2c, IOP3a and IOP4) were isolated and purified from Inonotus obliquus by DEAE-Sepharose fast flow and SepharoseCL-6B column chromatography. Their chemical and physical characteristics were determined and antioxidant activities were investigated on the basis of hydroxyl radical assay, superoxide radical assay and ferric-reducing antioxidant power assay. The results showed that five polysaccharides exhibited antioxidant activities, and the higher content of uronic acid and proteinous substances, the stronger antioxidant activities of polysaccharides. Besides, molecular weights of polysaccharides also influence their antioxidant activities. IOP3a and IOP4 showed higher antioxidant properties than IOP1b, IOP2a and IOP2c.

► Five antioxidant polysaccharides were isolated and purified from Inonotus obliquus.
► Five polysaccharides exhibit antioxidant activity in a concentration dependent manner.
► Uronic acid and molecular weight of polysaccharides influence antioxidant activity.