荭草苷与牡荆素调节细胞炎症的作用机制

植物来源的天然活性物质能够有效调节高脂膳食引起的氧化应激和低度炎症，是食品营养领域具有重要研究意义的热点问题。竹叶提取物能够有效调节氧化应激，对于人体健康具有促进作用，近来得到了广泛关注。水溶性的荭草苷、异荭草苷、牡荆素和异牡荆素等四种竹叶黄酮是竹叶提取物的主要功能物质，是其生物活性的主要来源。竹叶提取物中的特征性黄酮成分具有多种生理活性，然后其对炎症的调节机制尚不清晰，相关作用机理有待深入探究。江苏科技大学Yu Yue等在本研究中以竹叶提取物特征成分—荭草苷和牡荆素为研究对象，采用分子对接、生化表征、机制分析等探析了荭草苷与牡荆素调节细胞炎症的可能作用机制。

图1  荭草素和牡荆素并非通过与脂多糖竞争性结合TLR4受体发挥作用

 图2  荭草素和牡荆素通过调控MAPK通路发挥炎症调节作用的机制分析

研究结果表明，荭草素和牡荆素调节脂多糖诱导细胞炎症的作用方式并非通过与脂多糖竞争性结合TLR4受体发挥作用。荭草苷和牡荆素可以显著降低细胞的炎症因子水平，升高细胞抗氧化因子水平及抗氧化蛋白的表达，有效降低细胞内的ROS水平改善细胞的炎症水平；同时，荭草苷（或牡荆素）显著调节相关抗炎因子或蛋白的表达，减弱MARK三个亚基的磷酸化水平，抑制炎症因子NF-κB易位。综上，结合分子模拟及生化指标分析结果，荭草苷和牡荆素不与脂多糖竞争性结合TLR4受体；通过与MAPK的氨基酸残基结合，降低MAPK三个亚基的磷酸化水平，抑制NF-κB易位，同时通过激活细胞体内抗氧化防御体系，共同发挥抗炎活性。是荭草苷和牡荆素发挥抗炎活性的可能作用机制。

Orientin and vitexin attenuate lipopolysaccharide-induced inflammatory responses in RAW264.7 cells: a molecular docking study, biochemical characterization, and mechanism analysis

Yue Yu, Fusheng Pei, Zhanming Li*

School of Grain Science and Technology, Jiangsu University of Science and Technology, Zhenjiang 212004, China

*Corresponding author.

Abstract

Plant flavonoids have received considerable attention for their health benefits. However, structure-activity relationships between flavonoids such as orientin and vitexin with similar structures are rarely reported. In the present study, molecular docking study suggested that orientin and vitexin suppressed inflammatory responses through the modulation of the mitogen-activated protein kinase (MAPK) signaling pathway. Moreover, RAW264.7 cells with lipopolysaccharide-induced inflammation were used to evaluate the anti-inflammatory activities of orientin and vitexin, based on the inflammation-related cytokines production, quantitative real-time reverse transcription PCR, and western blotting analysis. As a result, orientin or vitexin attenuated inflammatory responses through modulation of the MAPK/NF-κB signaling pathway by suppressing NF-κB translocation.  

Reference:

YU Y, PEI F S, LI Z M. Orientin and vitexin attenuate lipopolysaccharide-induced inflammatory responses in RAW264.7 cells: a molecular docking study, biochemical characterization, and mechanism analysis[J]. Food Science and Human Wellness, 2022, 11(5): 1273-1281. DOI:10.1016/j.fshw.2022.04.024.