TH and Parkinson disease: Geniposide could also restore the number of tyrosine hydroxylase (TH)-positive dopaminergic neurons in the substantia nigra compact area, upregulate the level of the growth factor signalling molecule Bax and downregulate the expression of the apoptosis signalling molecule Bcl-2 to reduce cell apoptosis, thereby playing a role in the treatment of Parkinson's disease [97].