Functional properties of edible mushrooms.

Edible mushrooms such as shiitake may have important salutary effects on health or even in treating disease. A mushroom characteristically contains many different bioactive compounds with diverse biological activity, and the content and bioactivity of these compounds depend on how the mushroom is prepared and consumed. It is estimated that approximately 50% of the annual 5 million metric tons of cultivated edible mushrooms contain functional "nutraceutical" or medicinal properties. In order of decreasing cultivated tonnage, Lentinus (shiitake), Pleurotus (oyster), Auricularia (mu-er), Flammulina (enokitake), Tremella (yin-er), Hericium, and Grifola (maitake) mushrooms have various degrees of immunomodulatory, lipid-lowering, antitumor, and other beneficial or therapeutic health effects without any significant toxicity. Although the data for this functional food class are not as strong as those for other functional foods such as cruciferous vegetables, because of their potential usefulness in preventing or treating serious health conditions such as cancer, acquired immune deficiency syndrome (AIDS), and hypercholesterolemia, functional mushrooms deserve further serious investigation. Additionally, there is a need for epidemiological evidence of the role of this functional food class.

Immunomodulatory and antitumor activities of a polysaccharide-peptide complex from a mycelial culture of Tricholoma sp., a local edible mushroom.

A polysaccharide-peptide complex (PSPC) with immunomodulatory and antitumor activities was obtained from a submerged mycelial culture of Tricholoma sp., a local edible mushroom. The polysaccharide-peptide complex exhibited a molecular weight of 17 K in gel filtration and a single band after SDS-polyacrylamide gel electrophoresis. It was characterized by non-adsorption on both DEAE-Sepharose CL-6B and CM-cellulose. It could activate the macrophages, stimulate the proliferation of T-cells, and inhibit the growth of sarcoma 180 in mice. It possessed more potent immunomodulatory and antitumor activities than Coriolus versicolor polysaccharopeptide (PSP) and deserves to be studied as a potential agent for immunomodulation and cancer therapy.

Polysaccharide peptide (PSP) restores immunosuppression induced by cyclophosphamide in rats.

Polysaccharide peptide (PSP) is a protein-bound polysaccharide extracted from an edible mushroom, Coriolus versicolor. Effects of PSP (2g/kg/day) on cyclophosphamide (CPA, 40 mg/kg/2 days)-induced immunosuppression were investigated by determining lymphocyte proliferation, Natural killer (NK) cell formation, IgG and IL-2 concentration, WBC count and the weight of organs after rats were treated with or without CPA in the presence or absence of PSP. The results demonstrated that PSP possessed immunopotentiating effect, being effective in restoring CPA-induced immunosuppression such as depressed lymphocyte proliferation, Natural Killer cell function, production on white blood cell and the growth of spleen and thymus in rats as well as in increasing both IgG and IL-2 production on which CPA did not have significant effects under the conditions of our experiments. PSP can partly restore CPA-induced immunosuppression. Based on our findings and the data accumulated so far, it was suggested that PSP should be considered as an useful adjuvant especially combined with CPA or other chemotherapy in clinical treatment of cancer patients. The mechanism by which PSP restores the immunosuppression induced by CPA is unclear.

Effects of Lentinus edodes, Grifola frondosa and Pleurotus ostreatus administration on cancer outbreak, and activities of macrophages and lymphocytes in mice treated with a carcinogen, N-butyl-N-butanolnitrosoamine.

ICR mice were treated with a carcinogen, N-butyl-N'-butanolnitrosoamine BBN, every day for 8 consecutive weeks and the effects of oral administration of edible mushrooms on the induction of urinary bladder carcinoma and on the activities of macrophages and lymphocytes were studied. Bladder carcinoma were found in all 10 mice (100%) treated with BBN alone, while we observed carcinoma only in 9 of 17 mice (52.9%), in 7 of 15 mice (46.7%) and 13 of 20 mice (65.0%) treated with Lentinus edodes, Grifola frondosa and Pleurotus ostreatus, respectively. Chemotactic activity of macrophages was suppressed in mice treated with BBN alone but maintained almost the normal level in mice treated with BBN plus Lentinus, Grifola or Pleurotus. Lymphocytes collected from mice treated with BBN plus each mushroom showed almost normal blastogenic response against concanavalin A, although those from mice treated with BBN alone completely retarded their response. Cytotoxic activity of lymphocytes against Yac-1 cells was also maintained at a normal level in mice treated with BBN plus each mushroom. Whereas in mice treated with BBN alone significant depression of NK cell activity occurred. Significantly higher cytotoxic activity against P-815 cells was observed in lymphocytes from mice treated with BBN plus each mushroom than that in lymphocytes from normal mice or mice treated with BBN alone.

Free radical scavenging activities of mushroom polysaccharide extracts.

The superoxide and hydroxyl radical scavenging activities of eight mushroom antitumor polysaccharide extracts were investigated using phenazin methosulphate-NADH-nitroblue tetrazolium system and ascorbic acid-Cu(2+)-cytochrome C system respectively. The results showed that six of eight mushroom polysaccharide extracts had superoxide and hydroxyl radical scavenging activities. The protein content of the polysaccharide extracts appeared to contribute a direct effect on free radical scavenging activity. However, none of the mushroom polysaccharide extracts had antioxidative activity as measured by detecting malondialdehyde (MDA) contents of liver microsomes.