Anti-Inflammatory Effect of Taraxacum officinale Leaves on Lipopolysaccharide-Induced Inflammatory Responses in RAW 264.7 Cells
Anti-Inflammatory Effect of Taraxacum officinale Leaves on Lipopolysaccharide-Induced Inflammatory Responses in RAW 264.7 Cells
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DOI：
10.1089/jmf.2009.1249
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发表时间：
2010-08-01
影响因子：
2.4
通讯作者：
Choi, Hee-Don
中科院分区：
文献类型：
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作者：
Koh, Yoon-Jeoung;Cha, Dong-Soo;Choi, Hee-Don
为探讨蒲公英叶的抗炎作用及其机制，以小鼠巨噬细胞RAW 264.7为模型，研究蒲公英甲醇提取物及其提取物对脂多糖诱导的小鼠巨噬细胞的抗炎作用。用不同浓度的甲醇提取物及其组分对细胞进行预处理，然后与脂多糖(1ug/mL)孵育。采用酶联免疫吸附试验检测血清一氧化氮(NO)、前列腺素(PG)E(2)和促炎细胞因子肿瘤坏死因子(TNF)-α、白介素1-β(IL-1β)、白介素6(IL-6)水平。免疫印迹法检测诱导型一氧化氮合酶(INOS)和环氧合酶-2(COX-2)的表达及丝裂原活化蛋白(MAP)激酶的激活情况。甲醇提取物及其部分以剂量依赖的方式抑制内毒素诱导的NO、促炎细胞因子和PGE(2)的产生。氯仿部位对NO、PGE(2)和两种促炎细胞因子(肿瘤坏死因子-α和IL-1β)的产生呈剂量依赖关系，半数抑制浓度分别为66.51、90.96、114.76和171.06微克/毫升。乙酸乙酯部分也能抑制炎症分子的产生。氯仿和乙酸乙酯部位以剂量依赖的方式抑制内毒素诱导的iNOS和COX-2的表达以及MAP激酶的激活。在甲醇提取物的部分中，氯仿和乙酸乙酯部分显示出最有效的抗炎活性。这些结果表明，Tols的抗炎作用可能是通过失活MAP激酶信号通路，下调NO、PGE(2)和促炎细胞因子，减少iNOS和COX-2的表达。
To investigate the efficacy and the mechanism of the anti-inflammatory effect of Taraxacum officinale leaves (TOLs), the effect of a methanol extract and its fractions recovered from TOLs on lipopolysaccharide (LPS)-induced responses was studied in the mouse macrophage cell line, RAW 264.7. Cells were pretreated with various concentrations of the methanol extract and its fractions and subsequently incubated with LPS (1 mu g/mL). The levels of nitric oxide (NO), prostaglandin (PG) E(2), and pro-inflammatory cytokines including tumor necrosis factor (TNF)-alpha, interleukin (IL)-1 beta, and IL-6 were determined using enzyme-linked immunosorbent assays. Expressions of inducible NO synthase (iNOS) and cyclooxygenase (COX)-2 and activation of mitogen-activated protein (MAP) kinases were analyzed using western blotting. The methanol extract and its fractions inhibited LPS-induced production of NO, pro-inflammatory cytokines, and PGE(2) in a dosedependent manner. The chloroform fraction significantly suppressed production of NO, PGE(2), and two pro-inflammatory cytokines (TNF-alpha and IL-1 beta) in a dose-dependent manner with 50% inhibitory concentration values of 66.51, 90.96, 114.76, and 171.06 mu g/mL, respectively. The ethyl acetate fraction also inhibited production of the inflammatory molecules. The chloroform and ethyl acetate fractions reduced LPS-induced expressions of iNOS and COX-2 and activation of MAP kinases in a dose-dependent manner. Among the fractions of the methanol extract, the chloroform and ethyl acetate fractions exhibited the most effective anti-inflammatory activities. These results show that the anti-inflammatory effects of TOLs are probably due to down-regulation of NO, PGE(2), and pro-inflammatory cytokines and reduced expressions of iNOS and COX-2 via inactivation of the MAP kinase signal pathway.