Figure 1.

Comparative antioxidant activity of flavonoids measured via MTS assay. The comparative dose and time course-dependent antioxidant activity of liquiritin, liquiritigenin, isoliquiritigenin, naringenin, hydroxytyrosol, p-Coumaric acid, cinnamic acid, and tyrosol were determined for PC12 cells. Hydroxytyrosol demonstrated the strongest antioxidant activity compared to the other antioxidants. Data are mean and S.E. values from three independent experiments (n = 3). p < 0.01, relative to PC12 (control cells). * p < 0.05 and ** p < 0.01, relative to the cells treated only with salsolinol.