Dual effects of curcumin on neuronal oxidative stress in the presence of Cu(II)

► Cu(II) induces rat cortical neurons oxidative damage and apoptosis. ► At low doses, curcumin reverses the Cu(II)-induced neuronal oxidative damage. ► At high doses, curcumin in the presence of Cu(II) increases oxidative stress level. ► Curcumin potentially plays both anti-oxidative and pro-oxidative roles in organisms.