Abstract: This study aimed to improve the extraction yield and evaluate the immune modulatory activity of polysaccharides of Lepista sordida mycelia. Optimization of the extraction conditions was carried out using one-factor-at-a-time and orthogonal array design methods. The immune modulatory effect of the polysaccharides extracted was evaluated by measuring cell survival, TNF-α and IL-6 secretion, the percentage of neutral red phagocytosis and the expression levels of Toll-like receptor (TLR) TLR2 and TLR4 when mouse Ana-1 macrophages were exposed to different concentrations of the polysaccharides. The optimal extraction conditions were determined as follows: extraction temperature, 65 ℃; extraction time, 2.5 h; solvent-to-solid ratio, 40:1 (mL/g), leading to an extraction yield of 15.88%. In the concentration range of 0.05–1.6 mg/mL, the polysaccharides could promote the proliferation of macrophages, TLR2 and TLR4 expression, the phagocytosis of neutral red and TNF-α and IL-6 production; the most effective concentration was 1.6 mg/mL. These data illustrated that the polysaccharides possessed good immune modulatory activity.

Key words: Lepista sordida mycelium, polysaccharides, extraction, orthogonal array design, immune modulatory activities