In a mouse model, β-asarone treatment also exerted neuroprotective effects against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD, preventing the typical decrease in tyrosine hydroxylase (TH)-positive cells and increasing α-synuclein expression levels, thus protecting dopaminergic neurons in the midbrains [119] (Figure 4). The gene discussed is TH; the disease is Parkinson disease.