Sesamol suppresses the inflammatory response by inhibiting NF-κB/MAPK activation and upregulating AMP kinase signaling in RAW 264.7 macrophages.

OBJECTIVES AND DESIGN: Sesamol is a lignan isolated from sesame seed oil. In recent years, it was found that sesamol could decrease lung inflammation and lipopolysaccharide (LPS)-induced lung injury in rats. In this study, we investigated whether sesamol exhibited anti-inflammatory activity in LPS-stimulated macrophages. MATERIALS AND METHODS: RAW 264.7 cells were treated with sesamol, then treated with LPS to induce inflammation. The levels of proinflammatory cytokines were analyzed with ELISA. The gene and protein expression of cyclooxygenase (COX)-2, inducible nitric oxide synthase (iNOS), and nuclear factor erythroid-2-related factor 2 (Nrf2) were evaluated with real-time PCR and Western blots, respectively. We also examined inflammatory signaling pathways, including nuclear transcription factor kappa-B (NF-κB) and mitogen-activated protein kinase (MAPK) pathways. RESULTS: Sesamol inhibited production of nitric oxide, prostaglandin E2 (PGE2), and proinflammatory cytokines. Sesamol markedly suppressed mRNA and protein expression of iNOS and COX-2. Sesamol enhanced the protective antioxidant pathway represented by Nrf2 and HO-1. Moreover, sesamol suppressed NF-κB transport into the nucleus and decreased MAPK activation, but it promoted adenosine monophosphate-activated protein kinase (AMPK) activation. CONCLUSIONS: These data suggested that sesamol ameliorated inflammatory and oxidative damage by upregulating AMPK activation and Nrf2 signaling and blocking the NF-κB and MAPK signaling pathways.

Casticin inhibits COX-2 and iNOS expression via suppression of NF-κB and MAPK signaling in lipopolysaccharide-stimulated mouse macrophages.

ETHNOPHARMACOLOGICAL RELEVANCE: The fruits of Vitex rotundifolia L. are widely used to treat inflammation of the airway in Traditional Chinese medicine. Previous studies found that casticin, isolated from Vitex rotundifolia, could induce apoptosis of tumor cells. In this study, we evaluated the anti-inflammatory effects of casticin and its underlying molecular mechanism in lipopolysaccharide (LPS)-stimulated macrophages. MATERIALS AND METHODS: RAW264.7 cells were pretreated with various concentrations of casticin (0.3-10µM), and then treated with LPS to induce inflammation. We assayed the levels of proinflammatory cytokines and prostaglandin E2 (PGE2) using ELISA, and examined the protein expression of inducible nitric oxide synthase (iNOS), cyclooxygenase (COX)-2, and heme oxygenase (HO)-1 by Western blot. We also investigated the anti-inflammatory molecular mechanism by analyzing inflammatory-associated signaling pathways, including the nuclear transcription factor kappa-B (NF-κB) and mitogen-activated protein kinase (MAPK) pathways. RESULTS: We found casticin inhibited the levels of nitric oxide and PGE2, and decreased the production of proinflammatory cytokines such as interleukin (IL)-1ß, IL-6, and tumor necrosis factor α (TNF-α). In addition, iNOS and COX-2 expression levels were suppressed and casticin increased HO-1 and Nrf2 production in a concentration-dependent manner. Furthermore, casticin significantly inhibited NF-κB subunit p65 proteins in the nucleus and decreased Akt and MAPK activation. CONCLUSION: These results suggest that the anti-inflammatory effect of casticin is due to inhibition of proinflammatory cytokines and mediators by blocking the NF-κB, Akt, and MAPK signaling pathways.