College of Food and Pharmaceutical Sciences, Ningbo University, 315211, China.
College of Food and Pharmaceutical Sciences, Ningbo University, 315211, China; Key Laboratory of Animal Protein Food Deep Processing Technology of Zhejiang Province, Ningbo University, Ningbo, 315211, China.
J Ethnopharmacol. 2022 Mar 25;286:114897. doi: 10.1016/j.jep.2021.114897. Epub 2021 Dec 7.
Enteromorpha has long been recorded in traditional Chinese medicine, with cholesterol-lowering, anti-cancer, anti-inflammatory and antibacterial effects. Recently, we extracted the polyphenol-enriched fraction from Enteromorpha clathrata (E. clathrata) by ethyl acetate (ECPs), and isolated six individual polyphenols from ECPs via high-speed counter-current chromatography (HSCCC) with high-performance liquid chromatography (HPLC).
In this study, we explored the anti-inflammatory activity and underlying mechanism of ECPs in lipopolysaccharide (LPS)-induced RAW 264.7 macrophages.
ECPs and the six polyphenols were used for nitric oxide (NO) assay to identify the components with potent inflammation inhibitory effect. Enzyme-linked immunosorbent assay (ELISA), quantitative real-time PCR (qPCR), flow cytometry, and Western blot analysis were applied to further investigate their anti-inflammatory effects and underlying mechanism in LPS-stimulated RAW264.7 cells.
ECPs and the three individual polyphenols, including (-)-epicatechin, epigallocatechin-3-O-gallate and (-)-epicatechin-3-O-gallate, showed in vitro immunosuppressive activity by altering the cell biology at the gene, protein and functional levels in a dose- and species-dependent manner. Their anti-inflammatory effects were achieved by inhibiting LPS-induced production of nitric oxide and its upstream enzyme inducible nitric oxide synthase (iNOS), the pro-inflammatory cytokines including interleukin-1 beta (IL-1β), interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α), as well as the phagocytotic capacity, without cytotoxicity. The mechanism study further revealed that these anti-inflammatory properties were, at least partly, attributed to the suppressed activation of nuclear factor-κB (NF-κB) and p38 mitogen-activated protein kinase (MAPK) signaling pathways.
These findings indicated for the first time the correlation between the anti-inflammatory activity of ECPs and NF-κB and MAPK signaling pathways, suggesting that polyphenol-enriched organic fraction of E. clathrata could be potential candidate as therapeutic agent for treating inflammatory diseases.
裙带菜在中国传统医学中已有很长的记载，具有降低胆固醇、抗癌、抗炎和抗菌作用。最近，我们通过乙酸乙酯（ECPs）从裙带菜中提取了多酚富集馏分，并通过高效液相色谱（HPLC）结合高速逆流色谱（HSCCC）从 ECPs 中分离出六种单体多酚。
本研究旨在探讨 ECPs 在脂多糖（LPS）诱导的 RAW 264.7 巨噬细胞中的抗炎活性及其作用机制。
用 ECPs 和六种多酚进行一氧化氮（NO）测定，以鉴定具有较强抗炎抑制作用的成分。酶联免疫吸附测定（ELISA）、实时定量 PCR（qPCR）、流式细胞术和 Western blot 分析进一步研究了它们在 LPS 刺激的 RAW264.7 细胞中的抗炎作用及其作用机制。
ECPs 和三种单体多酚，包括（-）-表儿茶素、表没食子儿茶素-3-O-没食子酸酯和（-）-表儿茶素-3-O-没食子酸酯，通过改变基因、蛋白和功能水平，在剂量和物种依赖性方式下，改变细胞生物学，表现出体外免疫抑制活性。它们的抗炎作用是通过抑制 LPS 诱导的一氧化氮及其上游酶诱导型一氧化氮合酶（iNOS）、白细胞介素-1β（IL-1β）、白细胞介素-6（IL-6）和肿瘤坏死因子-α（TNF-α）等促炎细胞因子的产生，以及吞噬能力，而没有细胞毒性来实现的。机制研究进一步表明，这些抗炎特性至少部分归因于核因子-κB（NF-κB）和 p38 丝裂原活化蛋白激酶（MAPK）信号通路的抑制激活。
这些发现首次表明 ECPs 的抗炎活性与 NF-κB 和 MAPK 信号通路之间存在相关性，表明裙带菜多酚富集有机馏分可能是治疗炎症性疾病的潜在候选药物。
