| Summary: | 博士 === 臺灣大學 === 食品科技研究所 === 98 === Mushrooms have become popular sources of natural antitumor, antiviral, antibacterial, antioxidative, and immunomodulatory agents. Golden oyster mushroom, Pleurotus citrinopileatus, is a common mushroom in oriental countries for human consumption. In this study, we isolated a non-lectin functional protein (PCP-3A) from the fresh fruiting body of this mushroom and investigated its immunomodulatory and antitumor activities. Electrophoresis demonstrated that PCP-3A is a glycoprotein composed of 10 subunits, each approximately 45.0 kDa in size. In vitro cell study showed that PCP-3A inhibits the proliferation of human tumor cell line U937 in a time-dependent manner. To elucidate the mechanism of growth inhibition, flow cytometry revealed that it is capable of inhibiting the growth of U937 cells by way of S phase arrest and apoptotic induction. In addition, evaluation of the immunomodulatory effect showed that PCP-3A stimulated the secretion of cytokines TNF-α, INF-γ, IL-2, and IL-10 from human peripheral blood mononuclear cells. The anti-inflammatory of PCP-3A was also evaluated. PCP-3A was found to effectively inhibit NO generation on LPS-Induced RAW 264.7 cells. To elucidate the mechanism of NO reduction, the effects of PCP3-A on LPS-induced iNOS and COX-2 expression in RAW 264.7 cells were examined.There is positive correlation between the inhibition on the generation of NO and the expression of inducible nitric oxide synthase in macrophage.
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