MAOB and Parkinson disease: In the MPTP-induced PD, loss of dopaminergic neurons was revealed by post-mortem analysis, in which after penetrating the BBB, MPTP is metabolized into 1-methyk-4-phenylpyridinium (MPP+), by monoamine oxidase B (MAO-B), followed by the use of MPP+ by dopaminergic neuronal cells, resulting in blockage of complex 1 of the ETC [2].