Figure 5.

Effects of coffee extracts with different roasting degrees on promoter activity levels of NF-κB and ARE in LPS-stimulated RAW 264.7 cells. Cells were transfected with (A) NF-κB or (B) ARE reporter and co-transfected with pR-K-Renilla for internal normalization. At 24 h after transfection, cells were pretreated with four different roasting degrees of coffee extracts for 24 h and LPS was added. After four hours of LPS stimulation, total cells were lysed and luciferase activities were measured with a dual-luciferase system. Different alphabets indicate significant differences (p < 0.05). Each bar represents the mean ± standard error (n = 3). LPS, lipopolysaccharide; NF- κB, nuclear factor kappa-light-chain-enhancer of activated B cells; ARE, antioxidant response element.