Medicinal mushrooms are mushrooms that are used or studied as possible treatments for diseases. Research shows that various species of mushrooms produce antiviral, antimicrobial, anticancer, antihyperglycemic, cardioprotective, and anti-inflammatory compounds. Lentinan and PSK are mushroom extracts which are licensed pharmaceuticals in certain countries. Fungi that do not produce mushrooms, were the original source of penicillin, griseofulvin, mycophenolate, ciclosporin, mizoribine, mycophenolic acid, the first statins, and cephalosporins, and are used to produce paclitaxel. Mushrooms, fermentation molds, mycelia, and lichens, have a history of medicinal use spanning millennia. Ganoderma lucidum is the most famous medicinal mushroom, known in Chinese as ling zhi ("spirit plant"), and in Japanese as mannentake ("10,000 year mushroom"). Grifola frondosa was worth its weight in silver in ancient Japan. Inonotus obliquus was used in Russia as early as the 16th century, and its medicinal properties were described by Nobel laureate Alexandr Solzhenitsyn. Ancient Egyptians considered mushrooms food for royalty. Otzi the Iceman was found carrying Fomes fomentarius and Piptoporus betulinus. The Hadith states, "Truffles (Terfeziaceae) are manna which Allah sent to the people of Israel through Moses, and its juice is a medicine for the eyes." Lentinan is an intravenous anti-tumor polysaccharide isolated from the fruit body of shiitake (Lentinula edodes). Lentinan has been approved as
n adjuvant for stomach cancer in Japan since 1985. Lentinan is one of the host-mediated anti-cancer drugs which has been shown to affect host defense immune systems. Polysaccharide-K (International brand name: Krestin, PSK) is a protein-bound polysaccharide, which is used as an immune system boosting agent in the treatment of cancer in some countries in Europe as well as China and Japan. In Japan, PSK is approved as an adjuvant for cancer therapy and is covered by government health insurance. PSK is isolated from the mushroom Trametes versicolor. Preliminary evidence indicates PSK may have anticancer activity in vitro, in vivo and in human clinical trials. Preliminary research has also demonstrated that PSK may inhibit various cancer onset mechanisms. Preliminary evidence indicates PSK may have use as an adjuvant in the treatment of gastric, esophageal, colorectal, breast and lung cancers. Human clinical trials suggest PSK may affect cancer recurrence when used as an adjuvant, and basic research has demonstrated it inhibited certain human cancer cell lines in vitro. The MD Anderson Cancer Center reported that it is a "promising candidate for chemoprevention due to the multiple effects on the malignant process, limited side effects and safety of daily oral doses for extended periods of time." In fact, the Therapeutic Goods Administration in Australia reported that the WHO has only eight records of adverse effects with PSK and none reported for PSP.