Grifola frondosa This fungus forms large fan-shaped mushroom heads that often fuse together in masses at the base or on the roots of broadleaf trees. It can invade the core of the tree as a parasite causing extensive decay. It is often called ‘Hen of the Woods’ or ‘Sheep’s Head’ while it is more often called in Japan, Maitake, which mean ‘dancing nymph’.
In the early stages it is sought after for its delicious taste and excellent aroma. Previously, it was only collected from the wild and, consequently, was highly prized and priced. Since the late 1970s, it can be artificially cultivated on logs or sawdust mixtures and now many thousands of tons are being grown in Asia and more recently USA (Chen, 1999). In traditional Chinese medicine it has been used for improving spleen and stomach ailments, calming nerves and treating haemorrhoids (Hobbs, 1995). Maitake is a component of a wide range of Chinese medicines.
Recent studies have shown that polysaccharides and polysaccharide-protein complexes from this mushroom have significant anti-cancer activity (Hishida et al., 1988, Kurashige et al., 1997). A limited number of clinical studies in Japan and the USA have shown that a purified fraction of polysaccharide is highly effective against cancers of the breast, lung, liver, prostate and brain. Details of clinical trials will be discussed later. Other fractions from G. frondosa exhibit immunological enhancement together with properties of anti-HIV, antihypertension, antidiabetic, and antiobesity (Zhuang and Mizuno, 1999). It is interesting to note that the βglucan fractions from this mushroom are now being used by over 3,000 health professionals in the US for the prevention and treatment of : Flu and common infection (bacteria and viruses) AIDS (HIV) Diabetes mellitus Hypertension Hypercholesterolemia Urinary tract infections (particularly for women) (Professor Konno – personal communication). Capsules with dried Maitake form widely accepted dietary supplements and apart from the Far East are now being extensively marketed in US and in Europe. Other examples are Maitake tea, whole Maitake powder and a Maitake drink.
