Fig. 5. Theaflavin inhibits ROS production induced by ATP or nigericin.

BMDMs were first primed with LPS (500 ng/mL) for 4 h, and then pretreated with indicated doses of theaflavin for 1 h, followed by incubation with ATP (4 mM) for 30 min or nigericin (5 μM) for 1 h. Reactive oxygen species (ROS) in cells were detected by using 2′,7′-dichlorodihydrofluorescein diacetate (DCFH-DA) and observed by fluorescence microscopy. (b) and (d) show quantitative analyses of (a) and (c), respectively. Mitochondrial superoxide was assayed by staining with MitoSOX and observed by fluorescence microscopy. (g) and (h) are quantitative analyses of (e) and (f), respectively. Data are shown as mean ± SD (n = 5). Scale bars, 20 μm. *P < 0.05; ***P < 0.001; NI nigericin, TF theaflavin.