Anti-inflammatory properties of oolong tea(Camellia sinensis)ethanol extract and epigallocatechin gallate in LPS-induced RAW 264.7 cells

Objective: To evaluate the anti-inflammatory activity of oolong tea ethanol extract(OTEE) and epigallocatechin gallate(EGCG) on lipopolysaccharide-induced murine macrophage cell line(RAW 264.7).Methods: A cytotoxic assay using MTS tetrazolium was conducted to find a nontoxic level of OTEE and EGCG toward RAW 264.7 cells. Interleukins(IL-6, IL-1 b), tumor necrosis factor-a(TNF-a), and cyclooxigenase-2(COX-2) levels were measured by ELISA, and nitric oxide(NO) levels measured by a nitrate/nitrite colorimetric assay to determine the inhibition activity of OTEE and EGCG.Results: Lipopolysaccharide induction increases NO, COX-2, IL-6, IL-1 b, and TNF-a levels compared with the untreated cell(negative control). The positive control,lipopolysaccharide-induced RAW 264.7 without treatments showed the highest level of all pro-inflammatory cytokines and modulators tested in this study. The positive control was used as standard to obtain OTEE and EGCG inhibition activity toward NO, COX-2,IL-6, IL-1 b, and TNF-a. OTEE had a higher inhibition activity toward NO, COX-2, IL-6,and IL-1 b than EGCG; the reverse was seen for TNF-a. However, both OTEE and EGCG suppressed production of NO, COX-2, IL-6, IL-1 b, and TNF-a.Conclusions: OTEE and EGCG have the potential for use as anti-inflammatory drugs,which is shown by their ability to reduce the production of NO, COX-2, IL-6, IL-1 b, and TNF-a in active macrophages.