Medicinal mushroom extracts have shown promise as anti-cancer agents. There is a long history in China and Japan of using water extracts of certain mushrooms for their medicinal effects. There are 270 varieties of mushrooms that show medicinal value.
Mushroom species such as shiitake (Lentinus edodes), maitake (Grifola frondosa), Hericium erinaceus, Flammulina velutipes, Pleurotus ostreatus, and Tremella mesenterica are being recognized as containing medicinal chemicals. Non-edible mushrooms, such as reishi (Ganoderma lucidum), Schizophyllum commune, and Trametes versicolor, are used only medicinally. Ganoderma has been used for 4,000 years in Japan.
Anti-cancer polysaccharides are found in medicinal mushrooms. Most of these polysaccharides are nonspecific immune stimulants. The mushrooms are a rich source of medicines in Traditional Chinese Medicine (TCM). Some mushroom polysaccharides are toxic to cells and can cause illness. Clinical trials have been done on the following mushroom polysaccharides:
Lentinan, from L. edodes.
Schizophyllan, from S. commune.
PSK and PSP, from T. versicolor.
Grifron-D, from G. frondosa.
Lentinan and schizophyllan are given by abdominal injection, the rest are taken orally.
Little research has been done on the mechanism of action of the polysaccharides. They can stimulate the body’s natural immune system by stimulating immune cells and by stimulating the release of chemical messengers called cytokines. Cytokines include chemicals called interferons, interleukins, and colony stimulating factors, all chemicals that aid immunity.
Extracts of T. versicolor contain PSK and PSP, which are complexes containing proteoglycans. Proteoglycans are complexes of beta-D-glucans and proteins.
Clinical studies on mushrooms have only begun and are quite limited at this time. Griffon-D has been shown to be clinically safe. Lentinan, schizophyllan, PSK, and PSP are the best studied of the mushroom polysaccharides.
Lentinan has shown anti-cancer activity, prevents metastases and prevents both chemical-induced and viral-induced cancers in animal studies. The clinical studies of lentinan have not been well designed, however, lentinan does seem to show anti-cancer effects and reduces the side effects of standard cancer treatments, such as nausea, pain, and hair loss. There seems to be improvement in gastric and colorectal cancers with lentinan and it seems to be well tolerated by patients.
PSK has been studied in Japan against a wide range of cancers, especially gastric cancer. PSK doubled the two-year survival rate of gastric cancer patients when given in combination with standard chemotherapy.
PSP has been studied in China where it has been shown to improve appetite and fatigue in cancer patients and has improved a variety of blood elements. PSP has been shown to be of benefit in gastric, esophageal and non-small-cell lung cancers.
The Food and Drug Administration (1993) approved Grifron-D for clinical studies.
There are not sufficient studies at this time regarding possible interactions between mushroom polysaccharides and standard chemotherapy. The subject of purified extracts versus crude extracts remains controversial. The complexity of crude extracts may be a benefit in therapy.
CONCLUSION: Studies of medicinal mushrooms have mainly been done in Asia and the studies have been of poor quality according to scientific standards. The studies have shown benefit of the polysaccharide extracts of mushrooms against cancers. Further tests are indicated at this time, especially of extracts called lentinan, schizophyllan, Grifron-D, PSP, and PSK. Some of these extracts show improvement in cancer patients when they are used in combination with standard chemotherapy.
NOTE: Polysaccharides are complex carbohydrates. Read about the benefits of “Magic Mushrooms.” Read about the vitamin D and sterol composition of common mushrooms. Read more about the properties of beta-glucans.
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