| PDF (Download) | Maitake (Grifola frondosa) | | Date: September 24, 1998 | HC# 071388-141 |
Re: Immune Activity of Maitake
Schar, Douglas. Grifola frondosa: A 'New' Immunostimulant? British Journal of Phytotherapy. :.
This overview of the literature pertaining to the fungus Grifola frondosa, (commonly known as hen-of-the-woods or maitake) and its use as an immune stimulant, includes an interesting of literature references. The author, however, makes some serious errors in covering the topic, even referring to the fungus as a 'plant.' He is currently working on a book about maitake.
Maitake grows widely but not abundantly throughout North America, Europe and Asia. A saprophytic fungus, its usual host trees are oaks and other hardwoods, although this author says it occasionally grows on coniferous trees. Maitake fruiting bodies are composed of dozens of greyish fronds spring from a common base; single specimens can weigh up to a hundred pounds, although 5 to 10 pounds is typical. The mushroom is deliciously edible when tender. Maitake has been cultivated since the 1970's, making the mushroom much more widely available.
The article begins with a discussion of the history of European use and research on immunostimulating mushrooms that largely disregards the vast amount of medicinal mushroom research conducted in Asia. This is notable, since most of the later citations in this article draw on Japanese research. The author's failure to even mention shiitake (Lentinula edodes) in this section is striking. Of the author's list of seven polypore mushrooms and research on their antibacterial action, three were investigated by a European in 1946 and four by a Chinese researcher in 1989.
The following compounds have been found in maitake: amino acids, polysaccharide hydrolases, lignin hydrolases, proteases, haemagglutinin lectins, triglycerides and fatty acids, vitamins B1 and B2, provitamin D, potassium, phosphorus, magnesium, calcium, sodium, zinc, nucleotides, several other acids, and several sugars.
Several studies suggest that maitake polysaccharides stimulate macrophage and T-cell action. The author paraphrases one study in the following way: tumor-bearing mice whose immune system functions were blocked by a
immunosuppressive drug were injected with a maitake extract; it did not effectively inhibit tumor growth. Next, tumor-bearing mice treated with immune-system stimulating drugs were given maitake extract; the author says the 'extract was slightly more successful in reducing tumor size.' Something seems to have been lost in his interpretation; based on the results, it could easily be concluded that the maitake extract had no effect at all. The author says that to date, maitake research has been carried out with animals. He calls for 'full-scale human clinical trials.'
Some researchers have further theorized that intestinal bacteria could break maitake saccharides, which are too large to be absorbed by the gut, into smaller sugar molecules. When these smaller molecules leave the stomach and enter circulation, some investigators believe they bind with a protein and that the body mounts an immune system response against the new molecule.
Maitake may elicit the most powerful immune system response of any of the medicinal mushrooms that are widely available. Compared directly with shiitake, Agaricus bisporus, Pleurotus ostreatus, Flammulina velutipes, Pholiata glutinosa, Tremella fuciformis, Auricularia minor [Ed. Note: we don't know this specias], and Volvariella volvacea, maitake most effectively retarded cancer growth. In an animal trial maitake reduced tumors (it isn't clear whether in number or size) 86.6 percent, compared with shiitake's 54.4 percent.-Betsy Levy
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