Antioxidant properties of polysaccharides from Laetiporus sulphureus in submerged cultures

Abstract

Intracellular polysaccharides (IPS) and exopolysaccharides (EPS) are isolated respectively from mycelia and filtrates of submerged culture by Laetiporus sulphureus in 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 1.29×10,sup>6 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.

Key words: Laetiporus sulphureus, intracellular polysaccharide, exopolysaccharide, antioxidant activity.