Fig. 2.

Neuroprotective properties of sterubin. (A) Dose dependent effects of sterubin on HT22 cell total GSH levels in the absence or presence of 5 mM glutamate. GSH levels were measured after 24 h with a chemical assay. Results are the average of 3 independent experiments. *** p < 0.001 relative to control. (B) Comparison of the effects of 10 µM sterubin, eriodictyol and homoeriodictyol on basal GSH levels and GSH levels in the presence of 5 mM glutamate. GSH levels were measured after 24 h with a chemical assay. Results are the average of 3 independent experiments. *** p < 0.001 relative to control; # p < 0.05 relative to glutamate alone; ### p < 0.001 relative to glutamate alone. (C) Dose dependent effects of sterubin on HT22 cell survival in the presence of 500 nM erastin or 100 nM RSL3. Cell survival was measured after 24 h with the MTT assay. Results are the average of 3 independent experiments. (D) Dose dependent effects of sterubin and eriodictyol on basal and glutamate-induced ROS levels. Cells were treated with 5 mM glutamate alone or in the presence of the indicated concentrations of the compounds. After 7 h, ROS levels were determined using CM-H₂DCFDA as described in Experimental Procedures. The treatments were done in sextuplicate and the results are the average of 4 independent experiments. (E) Dose dependent effects of sterubin on HT22 cell survival in the presence of 5 µM tBOOH or 750 µM H₂O₂. Cell survival was measured after 24 h with the MTT assay. (F) Iron binding of sterubin, eriodictyol and homoeridictyol. Iron (Fe⁺²) binding by the flavanones was measured using the ferrozine assay at flavanone:iron ratios of 10:1, 5:1, 2:1 and 1:1. Results are presented as percent of Fe⁺² chelated relative to controls with no flavonoid and are the average of 3 independent experiments.