Agaricus blazei is an edible mushroom native to Brazil and is cultivated in Japan for medicinal uses. It has been used to treat arteriosclerosis, hepatitis, hyperlipidemia, diabetes, dermatitis, and cancer. The polysaccharides and anti-angiogenic compounds present in Agaricus are thought to be responsible for its antitumor properties. Agaricus was also shown to have antidiabetic effects in vitro and in animal studies (8) (9).
Results from a study done in human subjects with type 2 diabetes suggest benefits of Agaricus extract in improving insulin resistance (10) (11), and a pilot study indicates that Agaricus extract may reduce weight, body fat, and serum glucose and cholesterol levels in healthy individuals (12).
The antitumor and immunomodulatory effects of Agaricus are due to immunopotentiation or direct inhibition of angiogenesis (3) (4) (6) (21) (22). An Agaricus extract enhanced doxorubicin-induced apoptosis against drug-resistant human hepatocellular carcinoma (24).
Oral administration of the extract improved the natural killer cell activity and quality of life in gynecological cancer patients undergoing chemotherapy (7); preliminary data show that daily intake of Agaricus powder improves quality of life among cancer patients in remission (26). However, no such effects were seen in a study of elderly females (25). Larger studies are needed to resolve this.
While a small pilot study reported that Agaricus extract may improve liver function in patients with hepatitis B (13), liver damage and deaths (14) along with cheilitis (15) have been reported following consumption of Agaricus.
Brefeldin A, a compound isolated from Agaricus, was shown to have estrogenic activity, but did not stimulate growth of breast cancer cells (27).