Common Names
- PSK
- PSP
- VPS
- Turkey Tail
- Yun Zhi
- Kawaratake
- Krestin
For Patients & Caregivers
Coriolus versicolor extracts have been studied in cancer patients with some positive results. However, more studies are needed to verify their effects.
Coriolus versicolor is a mushroom that is used in traditional Chinese medicine as a tonic. PSK and PSP, polysaccharide compounds isolated from Coriolus, were shown to improve immune function in patients with certain cancers when used along with chemotherapy.
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To prevent and treat cancer
When used in combination with certain chemotherapy regimens, PSK has been shown to benefit patients following surgical removal of stomach and colorectal cancers. Clinical trials in patients with breast cancer, leukemias, and liver cancer do not show beneficial results. -
To reduce the side effects of chemotherapy
Animal studies suggest that PSK can prevent chemotherapy-induced immune suppression, but clinical trials have not been performed to confirm this effect in humans. -
To stimulate the immune system
Studies in animals and human volunteers suggest that PSK might stimulate the immune system. -
To treat infections
Coriolus’ effects against infections have not been studied in the laboratory or in clinical trials. -
To reduce the side effects of radiation therapy
Studies in mice and rats suggest that PSK can prevent radiation therapy-induced immune suppression, but this is yet to be proven in clinical trials.
For Healthcare Professionals
Coriolus versicolor is a mushroom of the Basidiomycetes class. It is used in traditional Chinese medicine as a tonic, and recent studies suggest that it has immunostimulant and anti-tumor properties. Polysaccharide-K (PSK), a proprietary product derived from Coriolus, was developed for cancer treatment in Japan. When used as an adjuvant, PSK appears to improve survival rates in patients with gastric (1) (2) and colorectal (3) (4) (5) cancers. It may also benefit patients with esophageal cancer (27).
Other Coriolus extracts, such as polysaccharide-peptide (PSP) and VPS, are available as dietary supplements. One clinical study demonstrated that when used in conjunction with chemotherapy, PSP may benefit patients with advanced non-small cell lung cancer (6). Other clinical studies using Coriolus extract alone or in combination with other botanicals also suggest positive immunomodulatory effects (7) (8). However, studies on breast cancer (9), hepatocellular carcinoma (10) (28), and leukemia (11) produced mixed results.
Coriolus extracts are generally well tolerated but minor adverse effects have been reported. Many over-the-counter Coriolus products are not standardized, making it difficult to compare potency between brands. It is also unclear if PSK, PSP, and other Coriolus extracts have comparable effects.
Coriolus versicolor is thought to be a biological response modifier. PSK induced cytokine expression in human peripheral blood mononuclear cells in vitro. In other studies, PSP as well as a Coriolus extract selectively induced apoptosis of human promyelocytic leukemia HL-60 cells (13) (23). PSP also increased apoptotic cell death in cells treated with camptothecin, reduced cellular proliferation, inhibited cell progression through S and G2 phases of DNA replication, reduced 3H-thymidine uptake, and prolonged DNA synthesis time (14). A medicinal mushroom blend that included Coriolus inhibited cell proliferation and induced cell cycle arrest at the G2/M phase in an invasive human breast cancer cell line (15). DNA-microarray analysis indicates the mushroom extract inhibits expression of cell-cycle regulatory genes and suppresses metastatic behavior via inhibition of cell adhesion, migration, and invasion. Inhibition of metastatic behavior was linked to suppression of urokinase plasminogen activator (15). PSP also inhibits interaction between HIV-1 gp120 and CD4 receptor, HIV-1 transcriptase activity, and glycohydrolase enzyme activity associated with viral glycosylation (16).
Several animal studies report synergy between PSK and biologic therapies, including a concanavalin A-bound L1210 vaccine and the IgG2a monoclonal antibody against human colon cancer cells (17). PSP induces cytokine production and T-cell proliferation, and prevents cyclophosphamide-induced immune suppression. Peritoneal macrophages isolated from PSP-fed mice show increased production of reactive nitrogen intermediates, superoxide anions, and tumor necrosis factor (18). PSP also shows analgesic activity in mouse models (19).
After consumption of PSP, non-small cell lung cancer patients have increased leukocyte and neutrophil counts, and increased serum IgG and IgM (6). Healthy volunteers as well as breast cancer patients who used a formula containing Coriolus and Salvia were found to have elevated counts of T-helper lymphocytes (CD4+), a high ratio of CD4+/CD8+, and elevated absolute counts of B-lymphocytes (7) (8). TNF-alpha and IL-8 gene expression were also found to be significantly induced after PSK administration in healthy volunteers and gastric cancer patients, although individual response varied (20). PSK induced apoptosis in promyelomonocytic leukemia HL-60 cells without inducing differentiation, and p38 MAPK was found to play an important role in this process (24).
Adverse reactions from Coriolus are rare, but passage of dark colored stools not originating from occult blood (21), darkening of fingernails (22), and low-grade hematological and gastrointestinal toxicities have been reported when used in conjunction with chemotherapy agents (3). However, such effects may be caused by the chemotherapy agents themselves.
High doses of a hot water extract of Coriolus were found to enhance development of large intestinal tumors in mice (12). However, this is not clinically relevant as the dosage is equivalent to 10-13 times higher than that used in human studies and the mice were injected with known potent carcinogens.