Figure 8.

Effects of 3′,4′-dihydroxyflavonol (DiOHF) on extracellular signal-regulated kinase (ERK)/p38 phosphorylation and nuclear factor-κB (NF-κB) activation. (A) Time course of ERK and p38 phosphorylation induced by platelet-derived growth factor (PDGF) (20 ng·mL⁻¹) and interleukin 1-β (IL-1β) (10 ng·mL⁻¹). Example from two independent experiments. (B) Concentration-dependent effects of DiOHF on basal and PDGF-induced ERK1/2 and p38 phosphorylation. Cells were pretreated with DiOHF for 1 h followed by PDGF stimulation (for 20 min). (C) Effects of DiOHF on IL-1β-induced ERK1/2 and p38 phosphorylation. Cells were pretreated with DiOHF for 1 h followed by IL-1β (for 20 min). All Western blot experiments in (B) and (C) were repeated three times. (D) Effects of DiOHF on IL-1β-induced p50 NF-κB activation. Cells were pretreated with DiOHF for 1 h followed by IL-1β for another hour. The DNA binding activity of p50 was assessed with a colorimetric transcription factor assay kit from Millipore (Billerica, MA, USA). The results were expressed as the difference of absorbance at 450 and 650 nm normalized to protein content. *P < 0.05 versus control, one-way anova, n= 3.