Medicinal mushrooms produce a vast array of chemical compounds, known as metabolites. These fungi, including well-known species like Reishi and Lion’s Mane, synthesize molecules that go beyond basic nutrition and are studied for their potential applications in human health. Understanding the specific nature of these metabolites provides insight into how these traditional remedies may exert their effects on the body.
Primary and Secondary Classification
Metabolites in medicinal mushrooms are broadly classified into two groups based on their function within the fungal organism. Primary metabolites are substances necessary for the fungus’s fundamental survival, growth, and reproduction. This group includes common molecules like amino acids, the building blocks of proteins, and basic sugars used for energy and structural components. Lipids and certain vitamins are also primary metabolites, continuously produced as part of the organism’s standard metabolic pathways.
Secondary metabolites are compounds not strictly required for immediate survival. These molecules are typically produced in response to environmental cues, stress, or competition. This category is chemically diverse and includes compounds associated with medicinal properties, such as terpenoids and alkaloids. The concentration of these secondary compounds can fluctuate significantly based on the mushroom’s growing conditions.
Ecological Function
Secondary metabolites often act as a chemical defense system for the mushroom in its natural environment. These compounds provide an evolutionary advantage against microbes, insects, or competing fungi in the substrate where the mushroom grows. For example, some secondary metabolites exhibit antibacterial or antifungal properties, helping the fungus secure its territory and food source.
Other compounds function as signaling molecules, facilitating communication with the surrounding ecosystem. Since this chemical warfare and signaling are energy-intensive processes, production is often initiated only when the fungus perceives an environmental threat or opportunity. The same molecules that help the mushroom survive in the wild are the ones that have demonstrated biological activity in human physiological systems.
Major Groups and Their Biological Activity
The health-supporting properties of medicinal mushrooms are attributed to several distinct chemical families, each with a unique structure and mechanism of action in the body.
Polysaccharides, particularly a subgroup called beta-glucans, are among the most studied compounds found in species like Turkey Tail and Reishi. These large carbohydrate molecules are characterized by a glucose backbone with specific beta-1,3 and beta-1,6 linkages, which are recognized by receptors on immune cells. This interaction allows beta-glucans to function as biological response modifiers, helping to modulate and support the body’s immune system.
Triterpenoids represent another significant class of molecules, especially abundant in the glossy cap of the Reishi mushroom (Ganoderma lucidum). These compounds are structurally similar to steroids and are known for contributing to the mushroom’s bitter taste. Over 100 different triterpenoids, such as ganoderic acids, have been isolated from Reishi, exhibiting various effects, including anti-inflammatory and antioxidant activities. The presence of these compounds is a primary reason Reishi is traditionally used to support general wellness and immune function.
Ergosterols are a type of sterol molecule found in the cell membranes of all fungi. Ergosterol is functionally analogous to cholesterol in animal cells, providing structural integrity to the mushroom’s cellular walls. This compound is also a precursor to Vitamin D2 (ergocalciferol). When a mushroom is exposed to ultraviolet light, the ergosterol is converted into this form of Vitamin D, supporting human bone health and immune function.
Specific species also contain unique compounds, such as the hericenones and erinacines found only in Lion’s Mane (Hericium erinaceus). Hericenones are aromatic compounds isolated from the fruiting body, while erinacines are diterpenoids found in higher concentrations in the mycelium. Both groups stimulate the synthesis of Nerve Growth Factor (NGF), a protein that promotes the growth and survival of nerve cells. These compounds are of high interest for their potential to support nerve and cognitive health.
Commercial Sourcing
The concentration of these beneficial metabolites varies significantly depending on which part of the fungus is used for commercial products. The fruiting body, the structure traditionally harvested, is generally found to contain the highest concentration of beta-glucans and triterpenoids. The mycelium, the root-like network often grown on a substrate like grain, can be a source of unique compounds such as the erinacines in Lion’s Mane.
The method of extraction is also a major factor in determining the final metabolite content of a supplement. Hot water extraction is the standard method for isolating the water-soluble compounds like polysaccharides, while alcohol (ethanol) extraction is typically used to concentrate the non-water-soluble compounds such as triterpenoids. For example, a dual extraction utilizing both water and alcohol is often performed on Reishi to capture the full spectrum of both the polysaccharides and the triterpenoids. Mycelium products grown on grain may contain a high percentage of residual starch, which can dilute the concentration of the actual mushroom metabolites.