Tianjin State Key Laboratory of Modern Chinese Medicine, Ministry of Education, Tianjin University of Traditional Chinese Medicine, Tianjin, China.
PLoS One. 2013 Jul 29;8(7):e69555. doi: 10.1371/journal.pone.0069555. Print 2013.
Oroxylin A, a natural flavonoid, is one of the main bioactive compounds that underlie the anti-inflammatory effect of the medicinal herb Scutellaria baicalensis Georgi widely used in southeastern Asia; however, the molecular mechanisms for the therapeutic benefits remain largely unclear. In this study, we found that Oroxylin A induces estrogen-responsive gene expression and promoter activity. In macrophages, Oroxylin A treatment significantly attenuates lipopolysaccharide (LPS)-induced but not basal inflammatory response, including nitric oxide (NO) production and the expression of inflammatory mediators (i.e., iNOS and COX-2) and cytokines (i.e., TNF-α, IL-1β, and IL-6), in an estrogen receptor (ER)-dependent manner. Oroxylin A treatment also dramatically decreases LPS-induced secretion of pro-inflammatory cytokines. Furthermore, the downregulation of all these inflammatory parameters by Oroxylin A was abolished when cells were pretreated with specific ER antagonist. Thus, Oroxylin A is a novel phytoestrogen and exhibits anti-inflammatory effects that are mediated by ER activity.
白杨素 A 是一种天然黄酮类化合物，是药用植物黄芩（Scutellaria baicalensis Georgi）抗炎作用的主要生物活性化合物之一，黄芩在东南亚被广泛使用；然而，其治疗益处的分子机制在很大程度上仍不清楚。在这项研究中，我们发现白杨素 A 可诱导雌激素反应基因的表达和启动子活性。在巨噬细胞中，白杨素 A 处理以雌激素受体（ER）依赖性方式显著减弱脂多糖（LPS）诱导的但不是基础炎症反应，包括一氧化氮（NO）的产生和炎症介质（即诱导型一氧化氮合酶（iNOS）和环氧化酶-2（COX-2））和细胞因子（即肿瘤坏死因子-α（TNF-α）、白细胞介素-1β（IL-1β）和白细胞介素-6（IL-6））的表达。白杨素 A 处理还显著降低 LPS 诱导的促炎细胞因子的分泌。此外，当细胞用特异性 ER 拮抗剂预处理时，白杨素 A 对所有这些炎症参数的下调作用均被消除。因此，白杨素 A 是一种新型植物雌激素，具有通过 ER 活性介导的抗炎作用。
