Immune-stimulatory potential of hot water extracts of selected edible mushrooms

Polysaccharides isolated from mushrooms have recently attracted attention due to its potential immune-stimulatory activity. The aim of this study was to validate the in vitro immune-stimulatory activities of various mushroom extracts. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay revealed that Pleurotus eryngii, with the highest -glucan (18.94%) content, displayed highest viability on macrophage cells of 62.59% at 200g/ml concentration. Pleurotus cystidiosus, with 18.16% -glucan, content showed highest activation of NF-kB (0.7 mu g/ml) at a concentration of 100 mu g/ml. Termitomyces heimii, with the lowest percentage of -glucan (0.51%), exhibited highest phagocytosis index of 9.38 at 12.5 mu g/ml. The brown strain of Agaricus bisporus with 1.54% of -glucan stimulates the highest nitric oxide (NO) production of 12.39 mu M nitrite oxide at 100 mu g/ml. This study revealed that hot water extracts of mushrooms have different -glucan contents and produced varying immune-stimulatory activities. Among these, Pleurotus spp. demonstrated the highest percentage of -glucan content and viability of macrophage cells. Pleurotus spp. are deemed immune-stimulatory by increasing phagocytic activity, NO production, and triggered the activation of NF-kB.