Role of plant-derived antioxidants on NF-kb expression in LPS-stimulated macrophages - biomed 2011.

The use of antioxidants has been shown to be beneficial in stimulating immune cells to increase phagocytosis and up-regulating the cellular processes to limit inflammation. Investigations into the specific mechanisms involved in the regulation of the inflammatory response in macrophages are broad; however, many researchers have found that regulating nuclear factor kappa B (NF-?B) may be a key component. The goal of this study was to assess the antioxidant potential of epigallocatechin-3-gallate (EGCG) (10µM) and thymoquinone (TQ) (10µM) on RAW 264.7 macrophages before and after being stimulated with lipopolysaccharide (LPS) (0.01 µg/mL). Our results showed that both EGCG and TQ, given individually, decreased NF-?B translocation in the nucleus when given before and after LPS stimulation. EGCG appeared to have the most impact on NF-?B in cells stimulated with LPS, but TQ was not as effective in inhibiting NF-?B in comparison to EGCG. The combination of EGCG and TQ showed a much higher level of NF-?B translocation compared to individual treatment, suggesting individual treatment may be more effective. In conclusion, we believe that EGCG and TQ may possibly block the upstream activation of mitogen activated protein kinase (MAPK) or inhibit the activity of the MAPK pathway, but further investigations are needed to understand the exact mechanisms of these observations.