Furthermore, catalpol (Bi et al., 2008b) was found to be a strong inhibitor of MAO-B, which may weaken the biotransformation of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine to 1-methyl-4-phenylpyridinium and the metabolism of DA; (6) Reduce α-synuclein accumulation: α-synuclein (α-syn) is a major component of lewy bodies that plays an important role in the pathogenesis of PD (Rocha et al., 2018). This evidence concerns the gene MAOB and Parkinson disease.