Comparative antioxidative characteristics of polysaccharide-enriched extracts from natural sclerotia and cultured mycelia in submerged fermentation of Inonotus obliquus

The potential antioxidant property of polysaccharide-enriched extracts from the natural fungal sclerotia and the cultured mycelia in submerged fermentation of Inonotus obliquus was evaluated using three antioxidant assays. The extracts from both the natural sclerotia and cultured mycelia including extra- and intra-cellular extracts were effective in scavenging hydroxyl radicals, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals, and in inhibiting lipid peroxidation. The content and type of polysaccharide present in the extracts from the natural sclerotia and the cultured mycelia were different. Both the extra- and intra-cellular extracts from the mycelia of I. obliquus with a higher polysaccharide content demonstrated a stronger free radical scavenger activity against hydroxyl radical and a greater inhibition of lipid peroxidation, shown as much lower IC50 values, than those from the natural sclerotia.