Maitake (mushroom)

Maitake (mushroom)

Maitake D-fraction: Healing and Preventing Potentials for Cancer

I have been studying medicinal mushrooms for the last 15 years and have reported that of all mushrooms studied, Maitake Mushroom (Grifola frondosa) has the strongest activity in tumor growth inhibition both in administered orally and intraperitoneally.( 1-3) In the tests of cancer inhibition rates on mice bearing MM46 (breast cancer), they were bred for one month with foods containing 20% edible mushroom powder. The result was that Maitake outperformed all other mushrooms. Through the 31 day oral administration, total remission of the tumor was visibly confirmed on four out of ten Maitake-fed mice. The remaining six rodents also indicated almost 90% suppression rate compared to untreated (control) mice. This is one of the reasons why Maitake is called King, among others. In fact, most other mushroom extracts are reported ineffective when given orally.( 4, 5) In this report, it is investigated if Maitake extract D-fraction is effective not only in the inhibition against tumors already growing, but also in the inhibition of formation of the secondary focus, due to metastasis of tumor cells in lymph and/or blood. Also, the results of human studies on Maitake D-fraction is reported.

Maitake, The King

Maitake (pronounced "my-tah-key") is indigenous to northern Japan. For hundreds of years, this rare and tasty mushroom has been prized in traditional Japanese herbology. Maitake literally means "Dancing Mushroom." People who found the mushroom in deep mountains started dancing with joy since they knew its delicious taste and the health bonefits. Also, in the feudal era, it could be exchanged with the same weight of silver. Maitake was, and still is, one of the most valuable and expensive mushrooms.

This legendary giant mushroom has been available by cultivation since the mid-1980's which gave opportunities for mycologists and pharmacologists to study the various medicinal properties of the mushroom as claimed in anecdotes and folklore. In addition to its antitumor effect, anti-hypertension, anti-diabetes, anti-obesity and anti-hepatitis activities have been found in Maitake. Its anti-HIV activity was also confirmed by both Japan National Institute of Health and U.S. National Cancer Institute in early 1992.

Maitake D-fraction

Among the various fractions in the process of standardization of the mushroom extraction, it is known that Maitake D-fraction is most potent in enhancing the immune system, demonstrating highest cancer inhibition in oral administration.( 3, 6) The protein bound Maitake D-fraction is the acidinsoluble, alkali-soluble and hot water extractable fraction ( 1, 6beta-glucans carrying 1,3 branched chains) with molecular weight of about one million.

Maitake D-fraction has strong ability to potentiate and activate the cellular immune system. We investigated how much each immune-competent cell is activated by the administration of Maitake D-fraction. Mice in experiment groups were administered either 0.5 mg/Kg of D-fraction by I.P. injection for 10 days or 1.0 mg/Kg of D-fraction by oral administration for 10 days. Natural Killer cells, cytotoxic T cells and delayed hypersensitive T cells were all activated by 1.5-2.2 times by Maitake D-fraction. Also, it was observed that the productions of interleukin-1 (which activates T cells), super-oxide anion (which damages tumor cells) were enhanced. The production of interleukin-2 was also observed to increase by 1.7 fold. It is confirmed that, for these results, the cellular immunecompetent cells to inhibit tumor growth were potentiated by Maitake D-fraction.

Strong Cancer Inhibitor

A number of animal tests have confirmed Maitake's strong ability in cancer inhibition,( 7-10) but human trials were not conducted until recently. This time, a non-randomized clinical study using D-fraction was conducted to see if it is as effective against advanced cancer patients as it is against animals. A total of 165 cancer patients have participated in the study and the data was collected under the cooperation of their medical doctors with major university hospitals and cancer treatment clinics in the western part of Japan. Patients were either taking Maitake D-fraction as crude powder tablets only or those with chemotherapy in addition. The results of the study indicate clearly that Maitake is effective against breast cancer, liver cancer and lung cancer but less effective against leukemia, stomach and bone cancers. The tumor regression or significant symptom improvements were observed among 11 out of 15 breast cancer patients, 12 out of 18 lung cancer patients and 7 out of 15 liver cancer patients. If taken with chemotherapy, these response rates improved by 12-28%. A number of patients have been diagnosed as stage I which had previously been stage III. Some drastic tumor reductions or remissions were also seen in many patients. A small chicken egg-sized brain tumor of a 44 year-old male was confirmed as completely disappeared after taking D-fraction for 4 months.

Also, it should be noted that most of the patients under the Maitake treatment claimed improvement of overall symptoms one way or another, even when the tumor regression was not observed. Various side effects from chemotherapy such as lost appetite, vomiting, nausea, hair loss, leukopenia (deficiency of white blood cells), etc., were ameliorated among 90% of the patients. Reduction of the pain was also reported from 83% of the patients.

Preventing Cancer Metastasis

Another interesting subject would be whether the formation of secondary focus due to metastasis of cancer cells could be inhibited by Maitake, i.e. whether Maitake can stop the metastasis? The test was conducted using mice in the following manner: MM-164 liver carcinoma (1 x 10( 7) cells) was injected in left rear footpad of mice and the footpad was cut off after 48 hours. Then, normal feed was given to the control group A, 20% Maitake powder was given to group B, and 1 mg/Kg of D-fraction was given to group C with normal food. All three groups were bred for another 30 days, and the number of tumor focus metastasized in the liver was counted by microscope. It is observed that the metastasis to the liver was prevented by 91.3% by the administration of D-fraction and by 81.3% by Maitake powder. It is believed that tumor cells present in blood and/or lymph were necrotized by the activated cellular immune-competent cells. The result of this animal test indicates that chances could be less than one-tenth of cancer metastasis if taking Maitake D-fraction every day.

Synergistic Effect with Chemotherapy

Maitake does not kill cancer cells directly. It stimulates the activities of immune competent cells and lets them fight with cancer cells. Chemotherapy is supposed to kill cancer cells directly. Then, which is more effective in terms of cancer growth inhibition? Here are some interesting results from my study on this effect. I used Mitomycin C (MMC) which is probably the most popular antibiotic drug used among doctors for various cancer treatments. It is known to be one of the strongest anti-cancer drugs, having very severe side effects as well. In my animal test, Maitake D-fraction, MMC, and both D-fraction and MMC (cutting each dose by half) were injected into tumor-bearing mice respectively. D-fraction alone demonstrated superior tumor growth inhibition to that of MMC (about 80% vs 45%). When MMC and D-fraction were given together, cutting each dose by half, tumor inhibition was further enhanced (nearly 98%). The result indicates some synergistic effect between MMC and Maitake, i.e., tumor cells are directly attacked by MMC while the immune system is activated by D-fraction. Chemotherapy is sometimes very critical as it lowers the immune system of the patients significantly. I have seen a lot of advanced cancer patients recover from severe side effects caused by chemotherapies by taking Maitake D-fraction (orally) together. I am very comfortable in saying that Maitake and chemo work together, or that you had better take Maitake when you have to take chemo.


Since the cultivation method of Maitake mushroom was established in mid-1980's, this legendary but delicious mushroom has gained much popularity among Japanese people. Anecdotes and folklore on its medicinal values have also been elucidated by a number of mycologists and pharmacologists. Among others, its strong anti-tumor activity has attracted many researchers. It should be noted that, unlike many other mushroom extracts that have to be injected intravenously, Maitake D-fraction has a strong ability to inhibit tumor growth when given orally as well. In this context, various tests were conducted focusing on cancer inhibition in its growth and metastasis after surgery by oral administration. Even though it was a limited and non-controlled trial, the clinical study indicated that Maitake D-fraction is effective against such cancers as Breast, Lung, Liver, Prostate and Brain. Also, both human and animal tests demonstrate the synergistic effect with chemotherapy while ameliorating severe side effects from chemos. Though it is still too preliminary to be conclusive, I would like to say that the result of animal (and limited) clinical studies based on Maitake D-fraction suggest significant healing and preventive potential for cancers and other immune-related health disorders. I would also like to add that, even among Maitake Mushrooms (Grifola frondosa), there are many strains, some of which contain little Beta-glucan, the active ingredient to stimulate the immune system. From such strains of Maitake, D-fraction may not be obtained.


(1.) Mori K, Toyomatsu T, Nanba H and Kuroda H, Antitumor Activities of Edible Mushrooms by Oral Administration. Int'l Symposium Scientific and Tech. The Penn Univ., July 1986.

(2.) Nanba H, Hamaguchi A and Kuroda H, The Chemical Structure of an Antitumor Polysaccharide in Fruit bodies of Grifola frondosa (Maitake), Chem Pharm. Bull. 34(3) 1162-1168, 1987.

(3.) Nanba H, Antitumor Activity of Orally Administered "D-fraction" from Maitake Mushroom (Grifola frondosa), J Naturopathic Med. 1993 (4) 1: 10-15.

(4.) Ohno N, Ito K, Takeyama T, Suzuki I, Sato K, Oikawa S and Miyazaki T, Structural characterization and Antitumor Activity of the Extracts from Matted Myaclium of cultured Grifola frondosa. Chem Pharm Bull, 33.3395 (1985).

(5.) Mizlino T, (Agr. Bid. Chen) Ohsawa K, Hagiwara N and Kuboyama R, Agric. Biol, Chem., 50., 1679 (1986).

(6.) Hishida 1, Nanba H and Kuroda H; Antitumor Activity Exhibited by Orally Administered Extract from Fruit Body of Grifola frondosa (Maitake) Chem. Farm Bull. 36 (5) 1819-1827, 1988.

(7.) Adachi K, Nanba H and Kuroda H, Potentiation of Host-Mediated Antitumor Activity in Mice by B-Glucan Obtained from Grifola frondosa, Chem Parm. Bull 35 (1) 262-270, 1987.

(8.) Iino K, Ohno N, Suzuki I, Sate K, Oikawa S, Yadomae T: Structure-function Relationship of Antitumor Beta 1,3-glucan Obtained from matted mycelium of Cultured Grifolo. frondosa, Chem Pharm Bull 33 (11): 4950-6, 1985.

(9.) Takeyama T, Suzuki I, Ohno N, Oikawa S, Sato K, Ohsawa M, Yadomae T; Host meditated Antitumor effect of Grifolan NMF-5N, A Polysaccharide Obtained from Grifola frondosa, J Pharmacobiodin, 10: 644-51, 1987.

(10.) Mizuno T, Kawagishi H, Mizuno K; Fractionation, Characterization and Formolysis of Antitumor Fibrous Polysaccharides (Non-Cellulose) from Maitake, the Fruiting Body of Grifola frondosa, Bull. Fac. Agr. Shieuoka Univ. No. 36, p.85-91, 1986.
Article copyright Townsend Letter for Doctors & Patients.
By Hiroaki Nanba

Share this with your friends