Inhibitory effect of epigallocatechin from Camellia sinensis leaves against pro-inflammatory mediator release in macrophages

To investigate the anti-inflammatory activity of natural products, we determined the anti-inflammatory activity of purified epigallocatechin (EGC) from Camellia sinensis leaves. In the present study, we found that EGC inhibited the production of proinflammatory mediators (IL-6, TNF-${\alpha}$, NO, and $PGE_2$) in lipopolysaccharide (LPS)-stimulated Raw 264.7 cells. Suppression of IL-6 seems to be at least partly attributable to the inhibitory effect of EGC. TNF-${\alpha}$ is a major cytokine produced by LPS-induced macrophages, and they have a wide variety of biological functions including regulation of inflammation. The inhibition of IL-6 and TNF-${\alpha}$ production by EGC may downregulate the acute-phase response to LPS, thereby reducing LPS-induced inflammation. In addition to IL-6 and TNF-${\alpha}$, EGC effectively reduced the production of other key inflammatory mediators, including NO and $PGE_2$. The inhibitory effect of EGC on NO and $PGE_2$ production was supported by the suppression of inducible nitric oxide synthase and COX-2 at protein levels. These results support the traditional use of EGC in the alleviation of various inflammation-associated diseases and suggest that EGC might be useful in the development of new functional foods for inflammatory diseases.