Anti-inflammatory effects of Phyllanthus amarus Schum. & Thonn. through inhibition of NF-κB, MAPK, and PI3K-Akt signaling pathways in LPS-induced human macrophages

Abstract

BackgroundPhyllanthus amarus has been used widely in various traditional medicines to treat swelling, sores, jaundice, inflammatory diseases, kidney disorders, diabetes and viral hepatitis, while its pharmacological and biochemical mechanisms underlying its anti-inflammatory properties have not been well investigated. The present study was carried out to investigate the effects of 80% ethanolic extract of P. amarus on pro-inflammatory mediators release in nuclear factor-kappa B (NF-кB), mitogen activated protein kinase (MAPK) and phosphatidylinositol 3-kinase/Akt (PI3K-Akt) signaling activation in lipopolysaccharide (LPS)-induced U937 human macrophages.MethodsThe release of prostaglandin E2 (PGE2) and pro-inflammatory cytokines, tumor necrosis factor (TNF)-α and interleukin (IL)-1β in a culture supernatant was determined by ELISA. Determination of cyclooxygenase-2 (COX-2) protein and the activation of MAPKs molecules (JNK, ERK and p38 MAPK), NF-κB and Akt in LPS-induced U937 human macrophages were investigated by immunoblot technique. The relative gene expression levels of COX-2 and pro-inflammatory cytokines were measured by using qRT-PCR. The major metabolites of P. amarus were qualitatively and quantitatively analyzed in the extract by using validated reversed-phase high performance liquid chromatography (HPLC) methods.ResultsP. amarus extract significantly inhibited the production of pro-inflammatory mediators (TNF-α, IL-1β, PGE2) and COX-2 protein expression in LPS-induced U937 human macrophages. P. amarus-pretreatment also significantly downregulated the increased mRNA transcription of pro-inflammatory markers (TNF-α, IL-1β, and COX-2) in respective LPS-induced U937 macrophages. It downregulated the phosphorylation of NF-κB (p65), IκBα, and IKKα/β and restored the degradation of IκBα, and attenuated the expression of Akt, JNK, ERK, and p38 MAPKs phosphorylation in a dose-dependent manner. P. amarus extract also downregulated the expression of upstream signaling molecules, TLR4 and MyD88, which play major role in activation of NF-κB, MAPK and PI3K-Akt signaling pathways. The quantitative amounts of lignans, phyllanthin, hypophyllahtin and niranthin, and polyphenols, gallic acid, geraniin, corilagin, and ellagic acid in the extract were determined by HPLC analysis.ConclusionThe study revealed that P. amarus targeted the NF-κB, MAPK and PI3K-Akt signaling pathways to exert its anti- inflammatory effects by downregulating the prospective inflammatory signaling mediators.Electronic supplementary materialThe online version of this article (10.1186/s12906-018-2289-3) contains supplementary material, which is available to authorized users.

Phyllanthin from Phyllanthus amarus inhibits LPS‐induced proinflammatory responses in U937 macrophages via downregulation of NF‐κB/MAPK/PI3K‐Akt signaling pathways

“…After the treatment, the cells were further incubated for 4 hr with 10% of Alamar blue reagents. Finally, the reduction of resazurin into resorufin by viable cells was read with microplate reader (Tecan Trading AG, Switzerland) at 570 nm (Harikrishnan, Jantan, Haque, & Kumolosasi, ).…”

Anti-inflammatory activities of puerarin in high-fat diet-fed rats with streptozotocin-induced gestational diabetes mellitus

“…The MyD88-dependent signalling pathway activated NF-κB to induce the inflammatory cytokine TNF-α [ 39 ]. Recent reports have shown that traditional Chinese medicines have therapeutic potential in inflammatory response and GDM [ 40 – 43 ]. Taking into account the inflammatory response involved in GDM [ 29 , 44 ], we evaluated the effects of puerarin treatment on IRS-1, TLR4, MyD88, and NF-κB expression in GDM rats.…”

PEP-1-GLRX1 Protein Exhibits Anti-Inflammatory Effects by Inhibiting the Activation of MAPK and NF-κB Pathways in Raw 264.7 Cells

“…Other studies have reported that phosphorylated IB and p-65 protein expression levels were markedly increased in cigarette-smoke-induced lung inflammation GLRX1 knockout mice (31). In addition, several studies have reported that the phosphorylated NF-B and MAPKs expression levels were increased in LPS-treated macrophages (39)(40)(41). In contrast, overexpression of GLRX1 decreased S-glutathionylation IKK Cys179 and increased NF-B activation after oxidation induced by oxidative stress, suggesting that cellular content of GLRX1 regulates the activation of NF-B under oxidative stress (42).…”