TH and Parkinson disease: Other compounds, such as iridoids (geniposide, harpagoside, catalpol, and 10-O-trans-p-coumaroylcatalpol), have demonstrated neuroprotective activity in Parkinson’s models by boosting antioxidant enzymes (e.g., glutathione peroxidase and superoxide dismutase) and increasing tyrosine hydroxylase-positive neurons [67].