Extraction of polysaccharides from Phellinus nigricans mycelia and their antioxidant activities in vitro.

In this study, response surface methodology was employed to optimize the extraction of polysaccharides from Phellinus nigricans mycelia. A central composite design was adopted to determine optimum parameters (extraction time, extraction temperature, extraction frequency, and ratio of water to raw material) that could yield a maximum polysaccharide. Results revealed the following optimum extraction conditions: extraction time, 2.8h; ratio of water to raw material, 28; extraction frequency, 5; and extraction temperature, 95 °C. Under optimized conditions, the experimental yield of P. nigricans mycelia polysaccharides was 15.33 ± 0.21%, which is consistent with the predicted yield. The antioxidant activity assay in vitro showed that the polysaccharides exhibited a high scavenging activity against superoxide anion, hydroxyl, and 1,1-diphenyl-2-picrylhydrazyl radicals. These polysaccharides also exhibited a strong reducing power. Thus, these polysaccharides can be used as natural antioxidants in functional foods or medicine.