<i>In vitro</i> antioxidant properties of polysaccharides from <i>Armillaria mellea</i> in batch fermentation

Abstract

Antioxidant properties of exopolysaccharides (EPS) and intracellular polysaccharides (IPS) obtained respectively from mycelia and filtrates of submerged culture by Armillaria mellea in a 20-L stirred tank bioreactor were investigated. Effective production of EPS and IPS is available by submerged culture of A. mellea with respective number average molecular weights and protein/polysaccharide ratios as 7.68×10⁶ Da and 7.68% as well as 5.65×10⁶ Da and 5.26%. Both EPS and IPS exhibit powerful antioxidant activities by conjugated diene method, chelating effect on ferrous ions and scavenging effect on superoxide anion, as evidenced by their quite low EC₅₀ values (< 5 mg/mL). Results confirmed that fermented A. mellea polysaccharides are potential antioxidant sources of both healthy medicine and food industries.

Key words: Armillaria mellea, intracellular polysaccharide, exopolysaccharide, antioxidant activity.