Treatment with Peanut Sprout Root Extract Alleviates Inflammation in a Lipopolysaccharide-Stimulated Mouse Macrophage Cell Line by Inhibiting the MAPK Signaling Pathway

Inflammation is a key response of the immune system to infection but aberrant inflammatory activity can lead to tissue damage and inflammatory diseases. Increasing evidence suggests that peanut sprout root extract (PSRE) has anti-inflammatory activity, and the aim of this study is therefore to investigate the effects of PSRE on the inflammatory response and the molecular mechanisms underpinning this effect in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. Using a combination of cell viability, ELISA, and nitric oxide (NO) assays, together with Western blotting, we showed that PSRE effectively inhibited NO production in LPS-stimulated cells and significantly reduced the expression of pro-inflammatory cytokines, including IL-6, IL-1β, and PGE2, at a dose of 200 µg/mL of PSRE, whereas TNF-α expression tended to decrease under PSRE treatment. We also confirmed a dose-dependent and significant inhibition of iNOS and COX-2 protein expression. In addition, PSRE treatment induced anti-inflammatory effects by inhibiting the phosphorylation of MAPKs (ERK, JNK, and p38) and NF-κB activation. Our results indicate that the anti-inflammatory properties of PSRE may result from inhibition of the MAPK pathways, which are known promoters of cytokine secretion.