Figure 2.

Antioxidative effect of tart cherry containing chlorogenic acid, quercetin, and kaempferol in HaCaT cells treated with PM₁₀. (A) Time-dependent response of PM₁₀ (100 μg/mL) on reactive oxygen species (ROS) production determined by staining HaCaT cells with 5-(and-6)-chloromethyl-2′,7′-dichlorodihydrofluorescein diacetate, acetyl ester (CM-H₂DCFDA). Data are represented as the means ± S.E. n = 3. * p ≤ 0.01 vs. 0 min. (B) Cells treated with PM₁₀ and tart cherry (TC, 200 μg/mL) for 15 min. Data are represented as the means ± S.E. n = 3. * p ≤ 0.01 vs. control. # p ≤ 0.001 vs. PM₁₀ alone. RFU, Relative fluorescence units. (C) ROS production (green) visualized by confocal microscopy. Scale bars, 100 μm (original magnification × 100). n = 3. (D) Ultra performance liquid chromatography (UPLC) profile of the commercial standard compounds. (E) UPLC profile of three major compounds in tart cherry. The insets indicate the chemical structure of chlorogenic acid, quercetin, and kaempferol, respectively. (F) Cells were pretreated with the antioxidant N-acetylcysteine (NAC, 10 μM) for 30 min prior exposure to PM₁₀ for 24 h. Cell viability was determined. Data are represented as the means ± S.E. n = 3. * p ≤ 0.001 vs. control. # p ≤ 0.01 vs. PM₁₀ alone.