Antioxidant and DNA damage protecting potentials of polysaccharide extracted from Phellinus baumii using a delignification method

•Polysaccharide of Phellinus was extracted with a delignification method.•Acid-chlorite delignification was a superior method to extract polysaccharide.•The purified polysaccharide showed noticeable antioxidant activity.•The protection against oxidative DNA damage of PPB-2 was found. A delignification method was employed to extract the polysaccharide from the fruiting body of Phellinus baumii. The three parameters, processing temperature, ratio of water to raw material and amount of acetic acid every time were optimized using the Box-Behnken design. As a result, the optimal extraction conditions were: processing temperature 70.3°C, ratio of water to raw material of 34.7mL/g and amount of acetic acid of 0.32mL every time. Under these conditions, the highest yield of polysaccharide (10.28%) was obtained. The main fraction (PPB-2) purified from PPB was composed of fucose, arabinose, galactose, glucose, xylose and mannose, while glucose was the predominant monosaccharide. PPB-2 exhibited noticeable antioxidant activity and strong protection against oxidative DNA damage. These findings implied that acid-chlorite delignification was a superior method to extract the polysaccharide from P. baumii and PPB-2 may be useful for cancer chemoprevention.