Figure 1. Attenuation of H₂O₂-induced cell damage by different concentrations (0.01 µM, 0.1 µM, 1 µM) of (A) HX, (B) HY and (C) HZ in undifferentiated PC12 cells.

Cells were incubated with 200 µM H₂O₂ for 2 h. Huprines were added to the culture 24–48 h prior to H₂O₂ addition. Cell viability was assessed by measuring the MTT reduction. At least three independent experiments were carried out in triplicate. The data are means ± s.e.m. expressed as percentage of control value. *P<0.05 compared with H₂O₂ group (Dunnett's test).