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-α, NO, and PGE2) 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-α 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-α production by EGC may downregulate the acute-phase response to LPS, thereby reducing LPS-induced inflammation. In addition to IL-6 and TNF-α, EGC effectively reduced the production of other key inflammatory mediators, including NO and PGE₂. The inhibitory effect of EGC on NO and PGE₂ 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 inflammationassociated diseases and suggest that EGC might be useful in the development of new functional foods for inflammatory diseases.