Shiitake (Lentinula edodes)

Shiitake (Lentinula edodes) is a gilled basidiomycete mushroom, widely cultivated and consumed as a food. In commercial contexts it is also often positioned as a “functional” ingredient, mainly due to its β-glucans and some characteristic compounds (e.g., lentinan and eritadenine). From a technical standpoint it is essential to distinguish between fruiting body (fresh/dried), powders, extracts (aqueous or hydroalcoholic), and mycelium: these matrices are not equivalent in terms of chemical profile, standardization, or data comparability. Correct taxonomic identification and supply-chain traceability remain key points for quality, safety, and claim interpretation.

Botanical classification

Mushroom characteristics

Ecology: predominantly saprotrophic on hardwood; in nature it colonizes logs and stumps, degrading the lignocellulosic matrix.

Fruiting body: a cap mushroom with gills (lamellate hymenophore); brown cap with a cuticle that varies by strain and cultivation conditions; the stem is often more fibrous (in cooking it is sometimes excluded or used for stocks).

Spores: generally light-colored spore print; morphological consistency is useful as a first-level check, but it does not replace more robust identification methods when required.

Part used: in the food chain, the fruiting body is mainly used (fresh or dried). In supplements and ingredient applications, fruiting body powder and extracts are also found; sometimes mycelium grown on substrate is used, with marker profiles that can differ from the fruiting body.

Technical note: drying and rehydration change the sensory fingerprint and the availability of some fractions (in particular aromatic volatiles and extractable polysaccharide fractions).

Chemical composition and structure

Composition varies with strain, substrate, harvest stage, and processing (fresh vs dried; extraction in water vs hydroalcoholic). The most relevant classes include cell-wall and storage polysaccharides, characteristic nitrogen compounds, sterols, sulfur volatiles, and micronutrients.

Polysaccharides: in shiitake, β-glucans with a β-(1→3) backbone and β-(1→6) branching are relevant, typical of many fungal fractions. Lentinan is a high-molecular-weight β-glucan frequently discussed in the literature as a “model” fraction; however, it is important to distinguish between purified lentinan and commercial “shiitake extracts,” which are often more heterogeneous.

Nitrogen compounds: eritadenine is a characteristic compound of shiitake frequently associated, in experimental literature, with effects on lipid metabolism. Its presence and quantification depend on the matrix and production conditions; it is not correct to assume comparable levels across different products without lot analysis.

Sterols: ergosterol is the main fungal sterol. It can be converted into vitamin D2 via UV exposure (natural or controlled), with major differences between “standard” shiitake and “UV-treated” shiitake in terms of labeling and specifications.

Volatile compounds: certain sulfur compounds contribute to the typical aroma (particularly evident in dried material and after cooking). This aspect is relevant for food applications and for sensory standardization.

Other compounds of interest: in edible mushrooms, ergothioneine is also often discussed as an antioxidant small molecule; levels can vary by species and lot, so any quantitative statement requires analytical data.

Uses and benefits

Food use: shiitake is used in soups, broths, sauces, and stir-fries; dried shiitake is often preferred to intensify umami and aromatic complexity, and for storage stability.

“Functional” use: in the supplement market, β-glucans and extractive fractions are typically emphasized. Evidence quality and data transferability depend critically on the true species, matrix (fruiting body vs mycelium), dose, extraction process, and degree of standardization.

Research: part of the literature concerns specific fractions (e.g., lentinan) used in experimental settings or regulated clinical contexts in some countries; such evidence is not automatically applicable to any non-standardized supplement.

Applications

Food and processing: fresh for quick preparations; dried for rehydration and for broth bases (with valorization of the soaking liquid). In the food industry it is also used in powders and flavor systems for an umami profile.

Supplements: capsules/powders of fruiting body, aqueous extracts (more oriented to polysaccharide fractions), and—depending on the producer—preparations with titration specifications. In multi-mushroom blends, transparency on percentages and standardizations becomes central.

Quality control: species identification (morphology and, if necessary, genetic markers), β-glucan quantification with consistent methods, verification of declared markers, and contaminant control (microbiology, metals, residues), especially in concentrated products.

Vitamin D2 enrichment: supply chains that include UV exposure require clear specifications and post-process analytical controls to support labeling.

Cultivation

Substrates: historically on hardwood logs; today cultivation on sawdust-based blocks and lignocellulosic matrices with supplements is very common, to optimize yield and uniformity.

Indicative parameters: fruiting is managed through control of humidity, aeration, temperature, and light, with protocols varying by strain and production system.

Variability: strain and substrate affect yield, polysaccharide profile, and markers, as well as sensory characteristics.

Environmental and safety considerations

Allergens and tolerability: as a cooked food it is generally well tolerated; gastrointestinal discomfort or skin reactions can occur in sensitive individuals, with greater attention warranted for concentrated extracts.

Shiitake “flagellate” dermatitis: a characteristic skin eruption has been described that may occur after ingestion of raw or undercooked shiitake; for practical prevention, adequate cooking remains the most relevant measure.

Interactions and prudent use: in the case of complex therapies or relevant clinical conditions, it is prudent to evaluate the use of concentrated extracts with a healthcare professional, because the transition from food to a concentrated preparation can change the risk profile.

Quality and authenticity: traceability, process specifications (including any UV treatment), contaminant controls, and consistency between claims and analyses are the most important factors for safety and product comparability.

Synonyms

shiitake

oakwood mushroom (en)

Lentinus edodes (historical synonym frequently found in the literature and on some labels)

References__________________________________________________________________________

Bugajewski M, Angerhoefer N, Pączek L, Kaleta B. Lentinula edodes as a Source of Bioactive Compounds with Therapeutical Potential in Intestinal Inflammation and Colorectal Cancer. Int J Mol Sci. 2025 Apr 2;26(7):3320. doi: 10.3390/ijms26073320. 

Abstract. Inflammatory bowel disease (IBD), including Crohn's disease (CD) and ulcerative colitis (UC), is a rising global health issue. Chronic intestinal inflammation is an important risk factor for colorectal cancer (CRC). Despite significant progress in IBD and CRC treatment, numerous patients remain resistant to standard pharmacotherapy or experience severe side effects that prevent them from continuing treatment. There is evidence suggesting that bioactive substances in Lentinula edodes have immunomodulatory and anticancer properties. This fungus is currently classified as a functional food, considering its beneficial effects on human health and special nutritional value. Studies conducted in vitro and in animal models demonstrated that L. edodes bioactive compounds, in particular glucans, have anti-inflammatory and antioxidant effects, induce apoptosis of cancer cells, reduce tumor angiogenesis, restore gut microbiome heterogeneity and improve gut barrier dysfunction. Moreover, clinical trials confirmed that these compounds combined with standard chemotherapy have a significant effect in improving the prognosis of CRC patients. In addition, L. edodes glucans increase microbial diversity and enhance interferon (IFN)-γ production by immune cells. Future studies must be focused on understanding the pathways and mechanisms associated with the observed effects. Moreover, both randomized trials and long-term follow-up studies are needed to confirm their effectiveness in the treatment of IBD and CRC.

Fukushima-Sakuno E. Bioactive small secondary metabolites from the mushrooms Lentinula edodes and Flammulina velutipes. J Antibiot (Tokyo). 2020 Oct;73(10):687-696. doi: 10.1038/s41429-020-0354-x.

Abstract. Mushrooms have been attracting attention as a source of bioactive compounds for the development of dietary supplements and medicines. Many researchers have reported pharmacological effects of edible mushrooms, and have isolated and identified bioactive substances. Lentinula edodes (shiitake) and Flammulina velutipes (enokitake) are the cultivated edible mushrooms that are popular throughout the world. In L. edodes, polyacetylenes and sulfur compounds have been shown to display antimicrobial activity. In F. velutipes, many types of bioactive terpenes have been reported from mycelium culture filtrate or solid culture substrate. This article reviews the bioactive metabolites of low-molecular weight from L. edodes and F. velutipes.

Shahbazi R, Yasavoli-Sharahi H, Alsadi N, Sharifzad F, Fang S, Cuenin C, Cahais V, Chung FF, Herceg Z, Matar C. Lentinula edodes Cultured Extract and Rouxiella badensis subsp. acadiensis (Canan SV-53) Intake Alleviates Immune Deregulation and Inflammation by Modulating Signaling Pathways and Epigenetic Mechanisms. Int J Mol Sci. 2023 Sep 27;24(19):14610. doi: 10.3390/ijms241914610. 

Abstract. Puberty is a critical developmental period of life characterized by marked physiological changes, including changes in the immune system and gut microbiota development. Exposure to inflammation induced by immune stressors during puberty has been found to stimulate central inflammation and lead to immune disturbance at distant sites from the gut; however, its enduring effects on gut immunity are not well explored. Therefore, in this study, we used a pubertal lipopolysaccharides (LPS)-induced inflammation mouse model to mimic pubertal exposure to inflammation and dysbiosis. We hypothesized that pubertal LPS-induced inflammation may cause long-term dysfunction in gut immunity by enduring dysregulation of inflammatory signaling and epigenetic changes, while prebiotic/probiotic intake may mitigate the gut immune system deregulation later in life. To this end, four-week-old female Balb/c mice were fed prebiotics/probiotics and exposed to LPS in the pubertal window. To better decipher the acute and enduring immunoprotective effects of biotic intake, we addressed the effect of treatment on interleukin (IL)-17 signaling related-cytokines and pathways. In addition, the effect of treatment on gut microbiota and epigenetic alterations, including changes in microRNA (miRNA) expression and DNA methylation, were studied. Our results revealed a significant dysregulation in selected cytokines, proteins, and miRNAs involved in key signaling pathways related to IL-17 production and function, including IL-17A and F, IL-6, IL-1β, transforming growth factor-β (TGF-β), signal transducer and activator of transcription-3 (STAT3), p-STAT3, forkhead box O1 (FOXO1), and miR-145 in the small intestine of adult mice challenged with LPS during puberty. In contrast, dietary interventions mitigated the lasting adverse effects of LPS on gut immune function, partly through epigenetic mechanisms. A DNA methylation analysis demonstrated that enduring changes in gut immunity in adult mice might be linked to differentially methylated genes, including Lpb, Rorc, Runx1, Il17ra, Rac1, Ccl5, and Il10, involved in Th17 cell differentiation and IL-17 production and signaling. In addition, prebiotic administration prevented LPS-induced changes in the gut microbiota in pubertal mice. Together, these results indicate that following a healthy diet rich in prebiotics and probiotics is an optimal strategy for programming immune system function in the critical developmental windows of life and controlling inflammation later in life.

Yanagimoto H, Hirooka S, Yamamoto T, Yamaki S, Sekimoto M. Efficacy of Lentinula edodes Mycelia Extract on Chemotherapy-Related Tasted Disorders in Pancreatic Cancer Patients. Nutr Cancer. 2023;75(1):236-246. doi: 10.1080/01635581.2022.2107226.

Abstract. Patients undergoing chemotherapy suffer from taste disorders that affect the quality of life (QOL). In this study, a randomized, double-blind, placebo-controlled trial was conducted to explore the effectiveness of AHCC®, a standardized extract of cultured Lentinula edodes mycelia, for chemotherapy-related adverse events and taste disorders in patients with gastrointestinal cancer. Patients who received chemotherapy were randomized to receive either placebo or AHCC®. The study endpoints were the incidence of anemia and taste disorders assessed with changes in nutritional parameters. Ninety-eight patients with pancreatic ductal adenocarcinoma (PDAC) were enrolled in this study, with 55 patients randomly assigned to the AHCC® group and 43 to the placebo group. The incidence of grades 2-3 anemia in the AHCC® group who were receiving chemotherapy was not significantly different compared to that of the placebo group (Risk difference; -3.1% [95% confidence intervals (CI): -22.8% to 16.9%], p = 0.8392). In the AHCC® group, the occurrence of taste disorders during chemotherapy was significantly lower, and the nutritional parameters were significantly improved compared to those in the placebo group (Risk difference; 28.6% [95% CI: 7.5% to 47.8%], p = 0.0077). AHCC® appears to prevent taste disorders in patients with advanced PDAC who were receiving chemotherapy. AHCC® is expected to enable patients who need chemotherapy to improve nutritional status and their QOL.

Shah SK, Walker PA, Moore-Olufemi SD, Sundaresan A, Kulkarni AD, Andrassy RJ. An evidence-based review of a Lentinula edodes mushroom extract as complementary therapy in the surgical oncology patient. JPEN J Parenter Enteral Nutr. 2011 Jul;35(4):449-58. doi: 10.1177/0148607110380684.

Abstract. The purpose of this review is to present the currently published evidence regarding the use, efficacy, potential mechanisms of action, and results of published clinical trials regarding the use of a Lentinula edodes mushroom-derived extract (active hexose correlated compound) as complementary therapy in patients with cancer. The authors explore the current preclinical and clinical evidence as it relates to this topic and its potential use in the surgical oncology patient. There has been a growing interest in stimulation of the immune system in trauma, cancer, and surgical patients in general. Little, however, has been written about some-of the supplements in widely used in Japan and China, but relatively unheard of in the United States.