Fig. 4

Effect of Duzhong compounds on MPP⁺ or MG132-induced neurotoxicity in the dopaminergic neuroblastoma SH-SY5Y cell line. Cells were exposed to 10 μM compound and 1 mM MPP⁺ or 200 μM MG132 for 24 h. Proteasomal peptidase activity (a) and cell viability (b) of SH-SY5Y cells were examined. Following treatment with seven compounds of Duzhong (10 μM each), five of the compounds (Bet, Wog, Oro, Ged, and Auc) significantly reversed MPP⁺-induced reduction in proteasome activity and attenuated the MG132-induced dysfunction of protease activity and cytotoxicity. Data are percentages of the control group. ^##p < 0.01 vs. control group, *p < 0.05, **p < 0.01 vs. MPP⁺ group, ^ap < 0.05, ^aap < 0.01 vs. MG132 group, n = 6