Artemisiae Iwayomogii Herba Protects Dopaminergic Neurons Against 1-Methyl-4-phenylpyridinium/1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine Neurotoxicity in Models of Parkinson’s Disease

<b>Background/Objectives:</b> Parkinson's disease (PD) is a common neurodegenerative disease characterized by motor symptoms caused by the loss of dopaminergic neurons. While the pathophysiology of PD is still not fully understood, it is recognized that oxidative stress plays a major role in its progression. Previous studies have shown that the aerial parts of <i>Artemisia iwayomogi</i> Kitamura (AIK) possess medicinal properties, including antioxidant activity. This study aimed to investigate whether AIK can alleviate neuronal loss and motor symptoms in a PD model and to explore its therapeutic mechanisms. <b>Methods:</b> For the in vitro study, PC12 cells were treated with AIK and 1-methyl-4-phenylpyridinium (MPP⁺). For the in vivo study, C57BL/6J mice were orally administered AIK for 12 days; they received intraperitoneal injections of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) for 5 consecutive days, starting on the 8th day of AIK administration. <b>Results:</b> AIK treatment to PC12 cells in the presence of MPP⁺ enhanced the phosphorylation of the protein kinase B/glycogen synthase kinase-3β signaling pathway, which is a crucial regulator of nuclear factor erythroid 2-related factor 2 (Nrf2) translocation. Additionally, AIK treatment increased cell survival and induced an antioxidant response involving heme oxygenase-1, via increasing the level of Nrf2 in the nucleus. In an MPTP-induced mouse model of PD, AIK administration activated Nrf2 in dopaminergic neurons and prevented the loss of dopaminergic neurons in the brain, which in turn alleviated motor dysfunction. <b>Conclusions:</b> Collectively, these findings suggest that AIK is a potential botanical candidate for PD treatment by protecting dopaminergic neurons through antioxidant activity.