Trametes versicolor, also known as Coriolus versicolor and Polyporus versicolor, is a common polypore mushroom found throughout the world. Meaning ‘of several colours’, versicolor reliably describes this mushroom found in different colors. By example, due to its resembling multiple colors in the tail of wild turkey, T. versicolor is commonly called turkey tail. The top surface of the cap shows typical concentric zones of different colours. The flesh is 1–3 mm thick and has leathery texture. It commonly grows in tiled layers. The cap is rust-brown or darker brown, sometimes with blackish zones.
Trametes versicolor contains polysaccharides under basic research, including the protein-bound PSP and B-1,3 and B-1,4 glucans. The lipid fraction contains the lanostane-type tetracyclic triterpenoid sterol ergosta-7,22,dien-3B-ol as well as fungisterol and B-sitosterol. Polysaccharide-K (PSK) displays anticancer activity in laboratory studies and in preliminary human research. PSK is possibly useful as an adjuvant in the treatment of gastric, esophageal, colorectal, breast and lung cancers. PSK adjuvants are under study for their potential to affect cancer recurrence. The U.S. Food and Drug Administration (FDA) recently approved a clinical trial for a turkey tail extract, allowing patients with advanced prostate cancer to take it in combination with conventional chemotherapy. Another trial pending FDA approval will test the effects of taking the extract along with a vaccine treatment in women with breast cancer. Polysaccharide-peptide (PSP), a peptide in Turkey Tail Mushroom, has been tested in rats to assess its interactions with pain (hot-plate test for tactile heat pain, acetic acid writhing test for chemical pain) and PSP appeared to have weak pain sensitizing effects relative to control. This increase in pain sensitivity appears to have been related to pro-inflammatory effects of PSP, and was significantly inhibited by anti-inflammatories. The polysaccharide PSK appears to be a TLR2 agonist, and can stimulate Natural Killer (NK) cells to produce IFN-γ and increase their cytotoxicity. An increased level of cytotoxic T-cells against tumors has been noted in animals fed PSK (100mg/kg) after injection of tumor cells.