中文摘要
由中藥黃芩根部萃取出來的黃芩素，在近來研究上具有抗氧化和抗發炎的藥效。許多研究指出，體內過量一氧化氮（nitric oxide, 簡稱NO）、前列腺素E2（prostaglandin PGE2, 簡稱PGE2）、自由基和腫瘤壞死因子-a（tumor necrosis factor-a, 簡稱TNF-a）與敗血性休克的形成有關。而過量NO與PGE2的生成分別是經由誘導型一氧化氮合成酵素（inducible nitric oxide synthase, 簡稱iNOS）與第二型環氧化酵素（cyclooxygenase-2, 簡稱COX-2）所產生。本研究是以內毒素（lipopolysaccharide, 簡稱LPS）刺激細胞株RAW264.7探討黃芩素對於NO、PGE2和TNF-a生成量的影響與iNOS及COX-2的表現。
從我們的結果可知，在以適當濃度LPS（仍可保持良好的細胞活性）刺激下的細胞株RAW264.7，隨著黃芩素處理濃度（10~50 mM）的增高，抑制NO、PGE2和TNF-a生成的效果越好。再者，黃芩素也可以抑制因LPS誘導所產生的iNOS及COX-2的mRNA與蛋白質表現。由結果可推知，黃芩素抑制iNOS及COX-2的mRNA與蛋白質表現的機轉可能是經由抑制TNF-a過量的生成。因此，黃芩素對於治療敗血性休克有很大潛力。另外，以50 mM黃芩素處理細胞株RAW264.7可降低細胞週期中S期和G2/M期的比例，所以黃芩素可能也可當為治療腫瘤的藥劑。

Abstract
It has been demonstrated that baicalin extracted from the root of Huangquin, a Chinese herb medicine has potential antioxidant and anti-inflammatory effect. Many studies have indicated that overproduction of nitric oxide (NO), from inducible nitric oxide synthase (iNOS), prostaglandin E2 (PGE2) from cyclooxygenase-2 (COX-2), free radical, and tumor necrosis factor-a (TNF-a) is involved in the pathogenesis of septic shock. In this study, we evaluated the effect of baicalin on these mediators and iNOS as well as COX-2 expression in lipopolysaccharide (LPS)-treated RAW264.7 macrophage.
Our results demonstrated that baicalin ( 10~50 mM ) concentration-dependently inhibited LPS-induced NO、TNF-a and PGE2 production in LPS-treated RAW264.7 macrophage without an appreciable cytotoxic effect. Furthermore, baicalin inhibited the expression of LPS-induced iNOS and COX-2 proteins and mRNAs. These results indicated that the inhibition of TNF-a production by baicalin maybe contribute to the suppression of iNOS and COX-2 expressions. Thus, baicalin may be beneficial for treatment of endotoxaemia. Besides, treatment of the RAW264.7 macrophage with 50 mM baicalin decreased the S phase and G2/M phase ratio about 15% in the cell cycle. Thus, baicalin may be also a potential therapeutic drug for tumor therapy.

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