The effects of inorganic selenium (sodium selenite) and Selol containing selenitetriglycerides synthesized from sunflower oil on mycelial growth and selenium-containing extracellular (EPS) and intracellular (IPS) polysaccharides production were examined in shake flask Cultures of Hericium erinaceum. Unlike sodium selenite which inhibited mycelial growth. Selol increased in biomass production in a dose-dependent manner. Selol also dramatically enhanced EPS formation to 2.25 g/L which is 2.5-fold higher than in the control. Selenium content in EPS and IPS obtained from Selol-enriched medium reached a maximum of 4.89 and 4.69 mg/g. respectively. The in vitro antioxidant activities of polysaccharicles were evaluated by reducing power, inhibition of lipid peroxidation, and 1,1-diphenyl-dipicrylhydrazyl radicals scavenging assays. The selenium-containing EPS showed an excellent antioxidant activity correlated well with increasing concentrations. The results suggested that selenium-containing EPS from H. erinaceum submerged culture should be explored as a novel selenium Source in dietary supplements, with potent antioxidant properties. (C) 2008 Elsevier Inc. All rights reserved.