At present there are more than 300 species of higher fungi (mushrooms) that are known to demonstrate therapeutic properties, hence the term medical mushrooms, or medicinal fungi. These properties are due to many compounds, notably steroids, lactones, alkaloids, polysaccharides and triterpenes that are contained within the fruiting bodies (which are colloquially called the mushrooms) and mycelium of the fungus. Pharmacologically, the polysaccharides are the main products of interest w.r.t. immune stimulating activities.

Some of these fungi, e.g. Lentinula, Grifola and Tremella, demonstrate medicinal and gastronomic properties while others, such as Ganoderma, Cordyceps and Trametes are known for their medicinal properties only. When used for a therapeutic intention the medicinal fungi are normally consumed as liquid extracts or dried powders from the fruiting body. A limited number of highly purified polysaccharide compounds derived from certain medicinal mushrooms are now being used, particularly in Asia, as pharmaceutical grade products.

POLYSACCHARIDES

Polysaccharides are found throughout nature. They are made up of many small sugar units linked together in different ways to form complex polysaccharides. One form of these, the beta glucans, is now attracting attention within the field of medicine because they display immunomodulatory properties and have an antitumour action.