Antioxidant properties of polysaccharides from Laetiporus sulphureus in submerged cultures

Intracellular polysaccharides (IPS) and exopolysaccharides (EPS) are isolated respectively from mycelia and filtrates of submerged culture by Laetiporus sulphureusin a 20-L stirred tank bioreactor with corresponding antioxidant properties investigated. Effective productions of IPS and EPS by submerged cultures of L. sulphureus are available. Number of average molecular weights (Mn) and protein/polysaccharide ratios are 1.29×106 Da and 8.24% for IPS and 3.95×106 Da and 2.38% for EPS. IPS shows an excellent antioxidant property in reducing power and scavenging effect on superoxide anion, whereas EPS has a powerful antioxidant activity in reducing power, chelating effect on ferrous ions and scavenging effect on superoxide anion, as evidenced by their quite low EC50 values below 5 mg/ml. Confirmed by the result is the potential antioxidant application of fermented L. sulphureus polysaccharides in health-promoting functional food and pharmaceutical industries.