Lentinus edodes(shiitake) has been consumed for more than 2000 years because of its nutritional value and health benefits. It has a low lipid content, high fiber content, and a considerable amount of proteins; it also contains B vitamins and minerals in addition to a wide range of functional metabolites including polysaccharides, polysaccharopeptides, lectins, and secondary metabolites with bioactivity, e.g., lentinan, a β-(1-3)-glucan with immunomodulatory activity, among others. Extracts and pure compounds of shiitake exhibit antibacterial, antifungal, cytostatic, antioxidant, anticancer, and immunomodulatory activity.  Some of the compounds shown to be created by Lentinus edodes are truly amazing. AHCC is an α-glucan-based standardized Lentinula edodes mycelium extract that has been extensively investigated as an immunostimulant both in animals and/or in humans affected by West Nile virus, influenza virus, avian influenza virus, hepatitis C virus, papillomavirus, herpes virus, hepatitis B virus and HIV by promoting a regulated and protective immune response. Although the efficacy of AHCC has not yet been specifically evaluated with respect to SARS-CoV-2 disease, its action in promoting a protective response to a wide range of viral infections, and the current absence of effective vaccines, could support its use in the prevention of diseases provoked by human pathogenic coronavirus, including COVID-19. Lentinan, a polysaccharide derived from L. edodes has been widely studied in terms of enhancing immune function. Lentinan is mainly composed of β-glucan with a 1,3 linkage.  The immunomodulatory activity and mechanisms of action of lentinan are well known. Lentinan triggers signaling pathways, such as MAPK-NF-κB and Syk-PKC, via binding pattern recognition receptors (TLR2, 4, 6, 9, Dectin-1) and the complement receptor, CD11b. Activation of these pathways stimulates the activity in immunocytes such as NK, macrophages and T cells.  Lentinan, Lentinula edodes-derived β-1→3,1→6-glucan, showed anti-inflammatory activity on an in vitro gut inflammation model. Furthermore, Lentinan significantly ameliorated DSS-induced colitis, indicating the potential application in treatment of gut inflammatory diseases such as ulcerative colitis and Crohn’s disease 
*These statements have not been evaluated by the FDA. This information is not intended to diagnose, treat, cure or prevent any disease.
 Gaitán-Hernández, R., López-Peña, D., Esqueda, M., & Gutiérrez, A. (n.d.). Review of Bioactive Molecules Production, Biomass, and Basidiomata of Shiitake Culinary-Medicinal Mushrooms, Lentinus edodes (Agaricomycetes). Retrieved from http://www.dl.begellhouse.com/journals/708ae68d64b17c52,11caa79135e177b5,042f94684dee8813.html
 Francesco DI PIERRO, Alexander BERTUCCIOLI, Ilaria CAVECCHIA,( 2020 Mar 12), Possible therapeutic role of a highly standardized mixture of active compounds derived from cultured Lentinula edodes mycelia (AHCC) in patients infected with 2019 novel coronavirus, Minerva Gastroenterologica e Dietologica EDIZIONI MINERVA MEDICA, DOI: 10.23736/S1121-421X.20.02697-5
 Chen, S., Liu, C., Huang, X., Hu, L., Huang, Y., Chen, H., … Nie, S. (2020, January 24). Comparison of immunomodulatory effects of three polysaccharide fractions from Lentinula edodes water extracts. Retrieved from https://www.sciencedirect.com/science/article/pii/S1756464620300153#b0170
 M. Zhang, Y.R. Zhang, L.J. Zhang, Q. TianMushroom polysaccharide lentinan for treating different types of cancers: A review of 12 years clinical studies in China, Progress in Molecular Biology and Translational Science, 163 (2019), pp. 297-328
 Xu, X., & Zhang, X. (2015, January 21). Lentinula edodes-derived polysaccharide alters the spatial structure of gut microbiota in mice. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4301806/