arachidin-1 and Inflammation

Arachidin-1 [trans-4-(3-methyl-1-butenyl)-3,5,3',4'-tetrahydroxystilbene] is a polyphenol produced by peanut kernels during germination. The aim of the present study was to investigate the mechanism underlying the anti-inflammatory effect of arachidin-1 in endothelial cells (ECs). The results of cell adhesion and western blotting assays demonstrated that arachidin-1 attenuated tumor necrosis factor (TNF)-α-induced monocyte/EC adhesion and intercellular adhesion molecule-1 (ICAM-1) expression. Arachidin-1 was demonstrated to exert its inhibitory effects by the attenuation of TNF-α-induced nuclear factor-κB (NF-κB) nuclear translocation and inhibitor of κB-α (IκBα) degradation. Furthermore, arachidin-1 upregulated nuclear factor-E2-related factor-2 (Nrf-2), a known mediator of phase II enzyme expression, and increased the transcriptional activity of antioxidant response element. Transfection of ECs with Nrf-2 siRNA blocked the inhibitory effect of arachidin-1 on ICAM-1 expression, NF-κB nuclear translocation and IκBα degradation. In addition, arachidin-1 induced the expression of the phase II enzymes thioredoxin-1, thioredoxin reductase-1, heme oxygenase-1, glutamyl-cysteine synthetase and glutathione S-transferase. Following arachidin-1 pretreatment, the H2O2-induced generation of reactive oxygen species was reduced. Therefore, the present results indicate that arachidin-1 suppresses TNF-α-induced inflammation in ECs through the upregulation of Nrf-2-related phase II enzyme expression.

Topics: Active Transport, Cell Nucleus; Arachis; Endothelial Cells; Gene Expression Regulation; Human Umbilical Vein Endothelial Cells; Humans; Hydrogen Peroxide; Inflammation; Intercellular Adhesion Molecule-1; Metabolic Detoxication, Phase II; NF-E2-Related Factor 2; NF-kappa B; NF-KappaB Inhibitor alpha; Reactive Oxygen Species; RNA, Small Interfering; Stilbenes; Transfection; Tumor Necrosis Factor-alpha

Biological activities of peanut stilbenoids, mainly resveratrol and its derivatives, have attracted increased attention and interest because of peanut being a potent producer and a dietary channel to convey these polyphenols to the human body. As arachidin-1 and piceatannol are structurally close to resveratrol, it is worthy to investigate their immunological activities on inhibition of lipopolysaccharide (LPS)-induced production of PGE2 and NO and mediation of the related transcription factors (NF-kappaB and C/EBP) of RAW 264.7 macrophage cells. Productions of PGE2 and NO were inhibited by all the test stilbenoids in a dose-dependent manner while gene and protein expressions of COX-2 and iNOS were not inhibited. As shown by NF-kappaB-driven luciferase assay, LPS-induced NF-kappaB activities were also reduced by the stilbenoids. In further, when these stilbenoids were subjected to monitoring their inhibitory effectiveness on LPS-induced transcription factor expressions of C/EBPdelta and C/EBPbeta, only C/EBPdelta expressions were reduced. Thus, these stilbenoids were effective in inhibition of PGE2- or NO-mediated inflammation and NF-kappaB- or C/EBPdelta-mediated inflammatory gene expression. In comparison, the highest inhibitory activity on LPS-induced PGE2/NO production, C/EBPdelta gene expression, and NF-kappaB activation was piceatannol which was followed in order by arachidin-1 and resveratrol. The observed anti-inflammatory activities of these peanut stilbenoids are of merit in further consideration for nutraceutical applications.

Topics: Animals; Anti-Inflammatory Agents; Arachis; Cell Line; Inflammation; Lipopolysaccharides; Macrophages; Mice; Resveratrol; Stilbenes