Medicinal Mushrooms Oyster (Pleurotus ostreatus) Pleurotus ostreatus contains 8 kinds of amino acids, as well as vitamin B1, B2 and vitamin P, while the dried mycelium is a source of B1, B2, B5 (niacin), B6 and B7 (biotin). One analysis of Oyster mushrooms (Eden and Wuensch, 1991) revealed appreciable amounts of all amino acids with the exception of tryptophan. The protein quality was high enough to nearly equal animal-derived protein. The main fatty acid in the fruit body is oleic acid, and the saturated to unsaturated fatty acid ratio is 14 (saturated) to 86 (unsaturated). Lectins have also been found in the fruit bodies and mycelium. The major organic acids in the fruit bodies include formic, malic, acetic (the most abundant at 266 mg/100 g) and citric acids. It is used in traditional medicine to treat infections, hyperlipidemia, diabetes, and cancer. In vitro experiments and studies done in mice have shown that Oyster mushrooms have antitumor, antifungal, lipid lowering, and hypoglycemic properties. The beneficial effects are due to the polysaccharides, lectins, and peptides present in Oyster mushrooms. A pilot study sponsored by the NationalCenter for Complementary and Alternative Medicine is underway to determine the lipid-lowering effects of Oyster mushrooms in patients with AIDS and hyperlipidemia. Purported usesCancer treatment Diabetes Hyperlipidemia Infections ConstituentsPolysaccharides: ß-1, 3-D-glucan, Pleuran Lectins Peptides: Pleurostrin Mevinolin A lectin isolated from the fruiting bodies of Oyster mushroom demonstrated antitumor activity in mice bearing sarcoma and hepatoma but the mechanism is not known. Pleurostrin, a peptide also derived from the fruiting bodies of Oyster mushroom, exhibited antifungal properties. Oyster mushrooms contain mevinolin that decreases cholesterol biosynthesis by inhibiting HMG CoA reductase, which is the rate limiting enzyme in cholesterol biosynthesis. Another study found that the development of precancerous aberrant crypt foci (ACF) was significantly reduced in mice that were fed a diet containing 10% pleuran, a beta-glucan isolated from Oyster mushrooms. The lectin exerted potent antitumor activity in mice bearing sarcoma S-180 and hepatoma H-22. Survival in these mice was prolonged and body weight increased after lectin treatment. | 
