Polysaccharides, one of the main bioactive components in natural resources such as plant, fungi, bacteria and algae, have attracted great attention in biomedical and functional food science due to their multiple therapeutic properties and low toxicity. The immunomodulatory effect is one of major pharmacological effects of polysaccharides. The immunomodulatory effects of polysaccharides from garlic and Chinese yam on RAW 264.7 macrophages have seldom been identified. Therefore, the study provided references for the applications of polysaccharide from garlic and Chinese yam. In this study, the effects of polysaccharides from garlic and Chinese yam on murine RAW 264.7 macrophages functions, such as phagocytic activity, NO release, cytokines’ productions were investigated. In Chapter 2, immunomodulatory effects of polysaccharides from fresh and black garlic were investigated and compared in vitro for the first time. The results indicated that fresh garlic polysaccharides exhibited stronger immunomodulatory activity than those of black garlic. The results of this work indicated that the polysaccharides isolated from fresh garlic could promote the immune functions of macrophages including phagocytosis, NO production, and several cytokines’ expression, while black garlic polysaccharides had little immunomodulatory effect. Our findings are helpful for the rational applications of polysaccharides from two sources of garlic. In Chapter 3, we reported the discovery of a non-starch polysaccharide (CYP) isolated and purified from Chinese yam (Dioscorea opposita Thunb.) and its immunomodulatory activities on RAW 264.7 macrophages in vitro. CYP promoted RAW 264.7 macrophages phagocytic activity, NO release, transcription and production of IL-6 and TNF-α. CYP induced NF-κB activation and IκBα degradation in RAW 264.7 cells. Notably, inhibition of Toll-like receptor 4 led to the suppression of CYP-induced NO production in RAW 264.7 cells. Our findings suggested that CYP exhibit the potential as functional food or therapeutic stimulant as a natural immune-stimulating polysaccharide.

多糖是植物、真菌、細菌和藻類等自然資源的主要活性成分。因為具有廣泛的生物 活性和較低的毒性，多糖在生物醫學和功能食品科學引起了極大關注。多糖的免疫 調節活性是多糖的一個主要的藥理作用。據報導，大蒜和山藥多糖對 RAW 264.7 巨 噬細胞免疫調節作用研究較少。因此，這項研究對大蒜以及山藥多糖的資源利用提 供了一定的依據。本文研究大蒜以及山藥多糖對小鼠腹腔巨噬細胞 RAW 264.7 功能 的影響，包括吞噬作用，NO 釋放，細胞因子分泌。第二章，白蒜和黑蒜多糖的免 疫調節作用被首次研究和比較。結果表明，與黑蒜多糖比較，白蒜多糖具有更強的 免疫調節作用。研究結果表明，白蒜多糖可以促進巨噬細胞的免疫功能，包括吞噬 作用，NO 釋放量，細胞因子的表達，而黑蒜多糖幾乎沒有免疫調節作用。我們的 發現有助於兩種大蒜的資源利用。在第三章，我們從淮山藥中分離和純化非澱粉山 藥多糖(CYP)，以及研究山藥多糖對 RAW 264.7 巨噬細胞體外免疫調節活性的影響。 山藥多糖增強巨噬細胞吞噬功能，NO 釋放，IL-6 和 TNF-α 的轉錄以及分泌。此外， 山藥多糖誘導 NF-κB 啟動以及抑制 IκBα 表達。值得注意的是，阻斷 toll 樣受體 4 抑制了山藥多糖誘導的巨噬細胞釋放 NO。我們的研究結果表明，山藥多糖可以開 發為功能性食品或天然的免疫刺激興奮劑。