FIGURE 5.

Protective effect of AO extracts on glutamate-induced oxidative stress. AO extract treatment reduced ROS levels in HT22 (A) and Neuro-2a (B) cells when compared to glutamate-treated cells. Representative fluorescence micrographs of HT22 (C) and Neuro-2a (D) cells stained with DCFH-DA were observed under a fluorescence microscope (10×) (Representative microscopy images from DCFH-DA, phase contrast and nuclear staining can be found in the Supplementary Material Figure S5. Samples were treated with AO extracts for 48 h and exposed to glutamate (G5: 5 mM glutamate, G10: 10 mM glutamate) for 12 h (HT22 cells) or 18 h (Neuro-2a cells) to induce oxidative stress. AO extract treatment increased endogenous antioxidant gene expression in HT22 (E) and Neuro-2a (F) cells when compared to untreated control. β-actin was used as the internal control for RT-PCR assay. The results are expressed as the means ± SEM of independent experiments (n = 3). *p < 0.05, **p < 0.01, ***p < 0.001 and ****p < 0.0001, compared to the untreated control; #p < 0.05, ##p < 0.01, ###p < 0.001 and ####p < 0.0001, compared to the group exposed to glutamate only.