Identification of plumericin as a potent new inhibitor of the NF‐κB pathway with anti‐inflammatory activity in vitro and in vivo

Abstract

BACKGROUND AND PURPOSEThe transcription factor NF-κB orchestrates many pro-inflammatory signals and its inhibition is considered a promising strategy to combat inflammation. Here we report the characterization of the natural product plumericin as a highly potent inhibitor of the NF-κB pathway with a novel chemical scaffold, which was isolated via a bioactivity-guided approach, from extracts of Himatanthus sucuuba, an Amazonian plant traditionally used to treat inflammation-related disorders.EXPERIMENTAL APPROACHA NF-κB luciferase reporter gene assay was used to identify NF-κB pathway inhibitors from H. sucuuba extracts. Monitoring of TNF-α-induced expression of the adhesion molecules VCAM-1, ICAM-1 and E-selectin by flow cytometry was used to confirm NF-κB inhibition in endothelial cells, and thioglycollate-induced peritonitis in mice to confirm effects in vivo. Western blotting and transfection experiments were used to investigate the mechanism of action of plumericin.KEY RESULTSPlumericin inhibited NF-κB-mediated transactivation of a luciferase reporter gene (IC50 1 μM), abolished TNF-α-induced expression of the adhesion molecules VCAM-1, ICAM-1 and E-selectin in endothelial cells and suppressed thioglycollate-induced peritonitis in mice. Plumericin exerted its NF-κB pathway inhibitory effect by blocking IκB phosphorylation and degradation. Plumericin also inhibited NF-κB activation induced by transfection with the constitutively active catalytic subunit of the IκB kinase (IKK-β), suggesting IKK involvement in the inhibitory action of this natural product.CONCLUSION AND IMPLICATIONSPlumericin is a potent inhibitor of NF-κB pathways with a new chemical scaffold. It could be further explored as a novel anti-inflammatory lead compound.

Therapeutic use of Fisetin and Fisetin Loaded on Mesoporous Carbon Nanoparticle (MCN) in Thioglycollate-induced Peritonitis

“…The thioglycollate-induced peritonitis in mice is used as a model to study the potential anti-inflammatory action of investigated test compounds [28]. In this present study, we have induced peritonitis in 6-8 weeks old BALB/c mice using thioglycollate, and then assessed the antiinflammatory effects of plant flavonoid, fisetin, when administered therapeutically.…”

Piperine Congeners as Inhibitors of Vascular Smooth Muscle Cell Proliferation

“…HUVECs (HUVECtert) were provided by Dr. Hannes Stockinger (Medical University of Vienna) [42,43]. Paclitaxel (taxol) and digitonin were obtained from Sigma-Aldrich with a purity of ≥ 95 % and~50 %, respectively.…”

“…HUVECtert were seeded in 96-well plates at 5 × 10 3 cells/well and incubated for 24 h (37°C, 5 % CO 2 ). Then, HUVECtert [42,43] were treated with compound or vehicle (0.1 % DMSO) as indicated and incubated for another 48 h. Afterwards, cells were washed with phosphate-buffered saline and incubated in culture medium containing 10 µg/mL resazurin for 2 h. The detection step was performed as described above. Results were expressed in RU compared to the fluorescence of PDGF/vehicle-treated control cells, which was set to 1.…”

“…Afterwards the supernatant of the treated cells was assessed for soluble cytosolic protein LDH activity, as an indicator for loss of cell membrane integrity and cell death [43,50]. For estimation of the total LDH, identically treated samples were incubated for 45 min in the presence of 1 % Triton X-100.…”

Discovery and resupply of pharmacologically active plant-derived natural products: A review

“…Other approaches resort to engineering of cells in vitro to stably overexpress, stably down-regulate, or knockout a gene product of interest (Ketting, 2011;Wang et al, 2014c). The spectrum of cell-based assays has been widened by engineering of cells enabled to act as reporters (e.g., luciferase-or fluorescence-based) of a specific intracellular response influenced by the tested substance (Baird et al, 2014;Fakhrudin et al, 2014). Aside of the use of reporter systems, a variety of phenotypic parameters have been successfully selected as readout, e.g., changes in cell morphology, cell adhesion, cell proliferation, migration, differentiation status, metabolic status, redox status, cell apoptosis or senescence (Atanasov et al, 2013b;Blazevic et al, 2014;Gaascht et al, 2014;Zheng et al, 2013).…”