| Component class |
Specific compound / fraction |
Typical source within shiitake |
Main structural type |
Approximate amount |
Main relevance |
Notes |
| Beta-glucan |
Lentinan |
Fruiting body cell wall; enriched by hot-water extraction |
β-(1→3) backbone with β-(1→6) branches; often triple-helix in active preparations |
About 4.1–5.5 mg/g dry weight in one quantified fruiting-body study; broader practical range often cited around 0.4–1.3% of dry weight |
Best-known shiitake anticancer / immunomodulatory beta-glucan |
This is the main named shiitake β-glucan. Amount varies a lot with strain, storage, and assay method. |
| Beta-glucan |
Total β-glucans |
Whole fruiting body, especially cap and stem cell walls |
Mixed fungal β-glucan pool, mostly β-linked wall glucans |
Pileus about 20.1–44.2% dry matter; stipe about 29.7–56.5% dry matter across cultivars |
Broad immune, fiber, and functional-food relevance |
Total β-glucan is much higher than lentinan alone. “Total β-glucan” should not be confused with lentinan content. |
| Beta-glucan |
β-(1→3),(1→6)-glucan fraction |
Purified polysaccharide fraction from shiitake |
Branched fungal β-glucan |
Usually reported as an isolated fraction rather than a fixed natural percentage |
Most likely to carry the classic lentinan-like immune activity |
This is the dominant medicinally relevant shiitake β-glucan architecture. |
| Beta-glucan |
β-(1→6)-glucan fraction |
Minor purified glucan fraction |
More linear / differently linked β-glucan fraction |
No reliable simple whole-mushroom percentage found |
Possible supportive bioactivity |
Reported in fractionation studies, but less emphasized than the β-(1→3),(1→6) fraction. |
| Alpha-glucan |
α-(1→3)-glucan fraction |
Cell-wall associated polysaccharide fraction |
α-glucan |
No simple whole-mushroom percentage established here |
Structural / possible adjunct bioactivity |
Important because shiitake contains more than just β-glucans. |
| Low-molecular-weight bioactive |
Eritadenine |
Free small molecule in caps, stems, and mycelium |
Purine-like alkaloid / adenine derivative |
Commonly reported around 50–70 mg/100 g dry weight in caps and 30–40 mg/100 g dry weight in stems; some reports are much higher depending on method |
Best known for cholesterol-lowering and methylation-related metabolic effects |
Not a glucan. Often listed among the major distinctive shiitake actives. |
| Sterol |
Ergosterol |
Membrane sterol in fruiting body tissues |
Fungal sterol; vitamin D2 precursor |
Examples around 294–478 mg/100 g dry weight; other reports extend into the low mg/g dry-weight range |
Nutritional relevance; precursor for UV-generated vitamin D2 |
Not a β-glucan, but one of the main recognized shiitake actives. |
| Organosulfur precursor |
Lentinic acid |
Present in dried shiitake; precursor pool changes with drying / rehydration |
Sulfur-containing flavor precursor |
Highly process-dependent; no single stable food-table value |
Precursor to aroma compounds and possible ancillary bioactivity |
Main importance is as precursor to lenthionine during processing and rehydration. |
| Organosulfur volatile |
Lenthionine |
Generated during drying / rehydration / processing from lentinic acid |
Cyclic organosulfur volatile |
One induced-cultivation study reported about 88.2 μg/g at peak conditions |
Characteristic shiitake aroma; possible antimicrobial / bioactive relevance |
More important as a flavor-signature compound than as the main medicinal constituent. |
| Phenolics / other metabolites |
Phenolics, terpenoids, sterols, peptides |
Distributed through fruiting body and extracts |
Mixed secondary-metabolite pool |
Usually reported as extract-dependent totals rather than stable whole-mushroom values |
Antioxidant, anti-inflammatory, and supportive nutraceutical effects |
Real but less standardized than lentinan, eritadenine, and ergosterol. |