Figure 3.

The neuroprotection effect of baicalein and daidzein against Aβ-induced cell death could be increased in the cotreatment. (a) Different concentrations of aggregated Aβ proteins (0, 1, 3, and 10 μM) were added into PC12 cells for 48 hours, or Aβ (10 μM) was added into the cultures for 1 to 3 days. Cell viability test using MTT colorimetric method was employed to determine the cytotoxicity of Aβ. (b) To determine the neuroprotection effect, PC12 cells were pretreated with baicalein (0.1, 1, 10 μM; upper panel) or daidzein (0.5, 5, and 50 μM; lower panel) for 24 hours before the addition of Aβ (10 μM) for 3 days. (c) Baicalein and daidzein at 0.1 μM + 0.5 μM (upper panel) and 0.1 μM + 0.5 μM (lower panel) were mixed together and then treated with PC12 cells for 24 hours before the addition of Aβ protein for cytotoxicity assay as in (b). Data are expressed as x Basal, whereas reading of control without drug or time 0 min is set as 1, mean ± SEM, n = 5. ***P < 0.001.