Center for Neurosciences and Cell Biology, University of Coimbra, Azinhaga de Santa Comba, 3004-517 Coimbra, Portugal.
J Ethnopharmacol. 2013 Jun 21;148(1):126-34. doi: 10.1016/j.jep.2013.03.077. Epub 2013 Apr 10.
Cymbopogon citratus (DC.) Stapf leaves infusion is used in traditional medicine for the treatment of inflammatory conditions, however little is known about their bioactive compounds.
Investigate the compounds responsible for anti-inflammatory potential of Cymbopogon citratus (Cy) on cytokines production induced by lipopolysaccharide (LPS) in human and mouse macrophages, and the action mechanisms involved.
An essential oil-free infusion of Cy was prepared and polyphenol-rich fractions (PFs) were obtained from it by column chromatography. Chlorogenic acid (CGA) was identified, by HPLC/PDA/ESI-MS(n). The expression of cytokines, namely TNF-α and CCL5, was analyzed by real-time RT-PCR, on LPS-stimulated human macrophages. Activation of nuclear factor (NF)-κB, a master regulator of inflammation, was investigated by western blot and gene reporter assay. Proteasome activity was assessed using a fluorogenic peptide.
Cymbopogon citratus extract and its polyphenols inhibited the cytokine production on human macrophages. This supports the anti-inflammatory activity of Cy polyphenols in physiologically relevant cells. Concerning the effect on the activation of NF-κB pathway, the results pointed to an inhibition of LPS-induced NF-κB activation by Cy and PFs. CGA was identified, by HPLC/PDA/ESI-MS(n), as the main phenolic acid of the Cy infusion, and it demonstrated to be, at least in part, responsible by that effect. Additionally, it was verified for the first time that Cy and PFs inhibited the proteasome activity, a complex that controls NF-κB activation, having CGA a strong contribution.
The results evidenced, for the first time, the anti-inflammatory properties of Cymbopogon citratus through proteasome inhibition and, consequently NF-κB pathway and cytokine expression. Additionally, Cy polyphenols, in particular chlorogenic acid, were highlighted as bioactive compounds.
香茅（DC。）的叶子浸剂被用于传统医学治疗炎症性疾病，但对其生物活性化合物知之甚少。
研究香茅（Cy）对抗炎症的化合物对脂多糖（LPS）诱导的人源和鼠源巨噬细胞细胞因子产生的影响，并探讨其作用机制。
制备香茅无精油浸剂，通过柱色谱法获得富含多酚的（PFs）部分。采用 HPLC/PDA/ESI-MS(n) 鉴定绿原酸（CGA）。通过实时 RT-PCR 分析 LPS 刺激的人源巨噬细胞中细胞因子（TNF-α和 CCL5）的表达。通过 Western blot 和基因报告测定法研究核因子（NF）-κB 的激活，NF-κB 是炎症的主要调控因子。采用荧光肽评估蛋白酶体活性。
香茅提取物及其多酚可抑制人源巨噬细胞细胞因子的产生。这支持 Cy 多酚在生理相关细胞中的抗炎活性。关于对 NF-κB 通路激活的影响，结果表明 Cy 和 PFs 抑制 LPS 诱导的 NF-κB 激活。采用 HPLC/PDA/ESI-MS(n) 鉴定出香茅浸剂中的主要酚酸为绿原酸，该化合物至少部分负责产生这种作用。此外，首次证明 Cy 和 PFs 通过抑制蛋白酶体来抑制 NF-κB 激活，而蛋白酶体是控制 NF-κB 激活的复合物，绿原酸对此有很强的贡献。
这些结果首次证明了香茅通过抑制蛋白酶体，进而抑制 NF-κB 通路和细胞因子表达来发挥抗炎作用。此外，Cy 多酚，特别是绿原酸，被认为是具有生物活性的化合物。
