EBE dose-dependently reduced PC12 cell death induced by 6-OHDA. PC12 cells were pretreated with or without EBE for 12 hours, pretreatment with 250 μM L-NAME for 12 hours served as positive control. The cells were exposed to 1 mM 6-OHDA for another 12 hours after pretreatment. (A) Cell viability was measured by MTT assay and results were expressed as percentage of control group (without 6-OHDA treatment). (B) Cell viability was measured as the percentage of released LDH. +++ P < 0.0001 versus control group (without 6-OHDA treatment); * P = 0.028 versus 6-OHDA group; *** P < 0.0001 versus 6-OHDA group. Each experiment was repeated 3 times.