Bottom Line: Coriolus versicolor extracts have been studied in cancer patients with some positive results. However, more studies are needed to verify such effects.
Coriolus versicolor is a mushroom that was 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 in conjuction with chemotherapy.
To prevent and treat cancer When used in combination with certain chemotherapy regimens, PSK has been shown to benefit patients who have undergone 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 no clinical trials have 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. Whether this stimulation results in improved fighting of disease has not been determined.
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.
Gastric Cancer: Two randomized, controlled clinical trials have examined the effectiveness of PSK in patients who underwent curative surgery (full removal of the tumor) for gastric cancer.
In the first study, the patients received 3 grams of PSK alone, normal chemotherapy alone, or chemotherapy and PSK together for one year, starting two weeks after surgery. After five years, the group that took chemotherapy and PSK had the highest survival rates.
In the second study, half of the patients alternated four weeks receiving fluorouracil, four weeks taking 3 grams of PSK daily, while the other half alternated four weeks of fluorouracil with four weeks of no treatment. Ten courses were given altogether. After five years, the PSK plus chemotherapy group had higher survival rates. However, only patients with a preserved immune response were allowed to take part in this study, so the results might not apply to immune-suppressed patients.
Colon Cancer: In randomized controlled study, patients received chemotherapy (5-FU) with or without 3 grams of PSK daily, starting after surgery. Chemotherapy was given for six months, while PSK was continued for three years. Those patients who had taken PSK had a higher average survival rate than those who had received chemotherapy alone.
Breast Cancer: PSK was combined with chemotherapy to measure its effects in patients undergoing surgical removal of operable breast cancer. The patients randomly received combination chemotherapy (5-fluorouracil, cyclophosphamide, mitomycin C, and predonisolone) with or without 3 grams of PSK daily. Each treatment cycle lasted 28 days and was carried out at 6-month intervals for 5 years. Those patients who took PSK along with chemotherapy had a slightly longer average survival time, but the difference was not statistically significant. More clinical trials are needed, and should test PSK in combination with other chemotherapy regimens.
This product is regulated by the F.D.A. as a dietary supplement. Unlike approved drugs, supplements are not required to be manufactured under specific standardized conditions. This product may not contain the labeled amount or may be contaminated. In addition, it may not have been tested for safety or effectiveness.
Low-grade toxicities have been reported when used in conjunction with chemotherapy agents. However, such effects may be caused by the chemo agents themselves.
PSK is approved for clinical use in Japan. Purified PSK, PSP extracts or raw Coriolus extract alone or in combination with other herbs were used in clinical studies. However, the clinical effects of these products have not been compared.
Coriolus versicolor is a mushroom of the Basidiomycetes class. It was used initially in Traditional Chinese medicine as a tonic, but 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. Other Coriolus extracts, such as polysaccharide-peptide (PSP) and VPS, are available as dietary supplements. When used in conjunction with chemotherapy, PSP may benefit patients with advanced non-small cell lung cancer (7). Other clinical studies using Coriolus extract alone or in combination with other botanicals also suggest positive immunomodulatory effects (8)(9). However, studies on breast cancer (10), hepatocellular carcinoma (11), and leukemia (12) produced mixed results. A hot water extract of Coriolus, VPS, was found to enhance development of large intestinal tumors in mice (21). 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. The proteoglycan constituents are thought to be responsible for its immunostimulant and anticancer activities. Many different mechanisms of action have been proposed. PSK induces cytokine expression in human peripheral blood mononuclear cells in vitro. TNF-alpha and IL-8 gene expression are significantly induced after PSK administration in healthy volunteers and gastric cancer patients, although individual response varies (13).
Several animal studies report of synergism between PSK and biologic therapies, including a concanavalin A-bound L1210 vaccine and the IgG2a monoclonal antibody against human colon cancer cells (14). PSP induces cytokine production and T-cell proliferation and prevents immune suppression due to cyclophosphamide in animal models. Peritoneal macrophages isolated from mice that were fed PSP show increased production of reactive nitrogen intermediates, superoxide anions, and tumor necrosis factor (15). PSP selectively induced apoptosis of human promyelocytic leukemia HL-60 cells (16). In vitro, PSP inhibits the interaction between HIV-1 gp120 and CD4 receptor, HIV-1 transcriptase activity, and glycohydrolase enzyme activity associated with viral glycosylation (17).
PSP also shows analgesic activity in mouse models (18). Non-small cell lung cancer patients have increased leukocyte and neutrophil counts, and increased serum IgG and IgM after consumption of PSP (7). 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+), high ratio of CD4+/CD8+), and elevated absolute counts of B-lymphocytes (8)(9).
Absorption Animal studies with radiolabeled PSK show that it is partially decomposed to small molecular products in the digestive tract. The full molecular spectrum of labeled PSK is absorbed within 24 hours following oral administration in mice. Peak plasma levels of low molecular weight substances occur at 0.5-1 h in rats and 1-2 h in rabbits, while molecules the size of PSK appear in serum after 4, 10, and 24 h. Distribution Radiolabeled PSK or its metabolites are detected in the digestive tract, bone marrow, salivary glands, thymus, adrenal gland, brain, liver, spleen, pancreas, and tumor tissue in sarcoma-bearing mice. Activity remains high longest in the liver and bone marrow. Excretion Approximately 70% of radiolabeled PSK is excreted in expired air, 20% in feces, 10% in urine, and 0.8% in bile. Approximately 86% is excreted within 24 h. (4)
Adverse reactions from Coriolus are rare. However, passage of dark colored stools (not originating from occult blood) (19), darkening of fingernails (20), 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 chemo agents themselves.
Wong CK, et al. Immunomodulatory effects of Yun Zhi and Danshen capsules in health subjects—a randomized, double-blind, placebo-controlled, crossover study. Int Immunopharmacology 2004;4:201-211. One hundred healthy subjects were given a combination of Yun Zhi (Coriolus versicolor, 50 mg/kg body weight) and Danshen (Salvia miltiorrhiza, 20mg/kg body weight) capsules or placebo for four months. After a 2-month washout period, subjects who received Coriolus and Salvia capsules were given placebo while those on placebo received Coriolus and Salvia capsules for another four months. Researchers used flow cytometry and cDNA expression arrays to assess immune functions and gene expression. Results indicated that oral consumption of Coriolus-Salvia capsules significantly increased the peripheral blood mononuclear cell (PBMC) gene expression of interleukin (IL-2) receptor, increased the percentage and absolute counts of T helper cell and ratio of Thelper/Tsuppressor cells, and also the production of interferon-gamma from PBMC. Since T helper cells participate in both cell mediated and humoral immunities, Coriolus-Salvia combination may be used to enhance immune function. Studies are being conducted in cancer patients to determine the immunomodulating potential of these agents.
A randomized, controlled, multicenter evaluation of chemotherapy with or without PSK in 262 patients after curative gastrectomy. Chemotherapy consisted of intravenous mitomycin C on postoperative days 1 and 7 plus 150 mg/d oral fluorouracil. The PSK group received 3 g/d oral PSK for 4 weeks alternating with 4 weeks fluorouracil, while control patients received only fluorouracil alternated with 4 weeks without treatment. Ten courses were given to both groups. PSK patients experienced a greater 5-year disease-free rate (70.7% vs. 59.4%) and 5-year survival rate (73% vs 60%) than the control group. Because eligibility criteria included a positive PPD, this trial only represents the benefits of PSK in patients with a preserved immune response.
